Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0-only
2 : /*
3 : * mm/mmap.c
4 : *
5 : * Written by obz.
6 : *
7 : * Address space accounting code <alan@lxorguk.ukuu.org.uk>
8 : */
9 :
10 : #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11 :
12 : #include <linux/kernel.h>
13 : #include <linux/slab.h>
14 : #include <linux/backing-dev.h>
15 : #include <linux/mm.h>
16 : #include <linux/mm_inline.h>
17 : #include <linux/shm.h>
18 : #include <linux/mman.h>
19 : #include <linux/pagemap.h>
20 : #include <linux/swap.h>
21 : #include <linux/syscalls.h>
22 : #include <linux/capability.h>
23 : #include <linux/init.h>
24 : #include <linux/file.h>
25 : #include <linux/fs.h>
26 : #include <linux/personality.h>
27 : #include <linux/security.h>
28 : #include <linux/hugetlb.h>
29 : #include <linux/shmem_fs.h>
30 : #include <linux/profile.h>
31 : #include <linux/export.h>
32 : #include <linux/mount.h>
33 : #include <linux/mempolicy.h>
34 : #include <linux/rmap.h>
35 : #include <linux/mmu_notifier.h>
36 : #include <linux/mmdebug.h>
37 : #include <linux/perf_event.h>
38 : #include <linux/audit.h>
39 : #include <linux/khugepaged.h>
40 : #include <linux/uprobes.h>
41 : #include <linux/notifier.h>
42 : #include <linux/memory.h>
43 : #include <linux/printk.h>
44 : #include <linux/userfaultfd_k.h>
45 : #include <linux/moduleparam.h>
46 : #include <linux/pkeys.h>
47 : #include <linux/oom.h>
48 : #include <linux/sched/mm.h>
49 :
50 : #include <linux/uaccess.h>
51 : #include <asm/cacheflush.h>
52 : #include <asm/tlb.h>
53 : #include <asm/mmu_context.h>
54 :
55 : #define CREATE_TRACE_POINTS
56 : #include <trace/events/mmap.h>
57 :
58 : #include "internal.h"
59 :
60 : #ifndef arch_mmap_check
61 : #define arch_mmap_check(addr, len, flags) (0)
62 : #endif
63 :
64 : #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
65 : const int mmap_rnd_bits_min = CONFIG_ARCH_MMAP_RND_BITS_MIN;
66 : const int mmap_rnd_bits_max = CONFIG_ARCH_MMAP_RND_BITS_MAX;
67 : int mmap_rnd_bits __read_mostly = CONFIG_ARCH_MMAP_RND_BITS;
68 : #endif
69 : #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
70 : const int mmap_rnd_compat_bits_min = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MIN;
71 : const int mmap_rnd_compat_bits_max = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MAX;
72 : int mmap_rnd_compat_bits __read_mostly = CONFIG_ARCH_MMAP_RND_COMPAT_BITS;
73 : #endif
74 :
75 : static bool ignore_rlimit_data;
76 : core_param(ignore_rlimit_data, ignore_rlimit_data, bool, 0644);
77 :
78 : static void unmap_region(struct mm_struct *mm, struct maple_tree *mt,
79 : struct vm_area_struct *vma, struct vm_area_struct *prev,
80 : struct vm_area_struct *next, unsigned long start,
81 : unsigned long end, bool mm_wr_locked);
82 :
83 : static pgprot_t vm_pgprot_modify(pgprot_t oldprot, unsigned long vm_flags)
84 : {
85 0 : return pgprot_modify(oldprot, vm_get_page_prot(vm_flags));
86 : }
87 :
88 : /* Update vma->vm_page_prot to reflect vma->vm_flags. */
89 0 : void vma_set_page_prot(struct vm_area_struct *vma)
90 : {
91 0 : unsigned long vm_flags = vma->vm_flags;
92 : pgprot_t vm_page_prot;
93 :
94 0 : vm_page_prot = vm_pgprot_modify(vma->vm_page_prot, vm_flags);
95 0 : if (vma_wants_writenotify(vma, vm_page_prot)) {
96 0 : vm_flags &= ~VM_SHARED;
97 0 : vm_page_prot = vm_pgprot_modify(vm_page_prot, vm_flags);
98 : }
99 : /* remove_protection_ptes reads vma->vm_page_prot without mmap_lock */
100 0 : WRITE_ONCE(vma->vm_page_prot, vm_page_prot);
101 0 : }
102 :
103 : /*
104 : * Requires inode->i_mapping->i_mmap_rwsem
105 : */
106 : static void __remove_shared_vm_struct(struct vm_area_struct *vma,
107 : struct file *file, struct address_space *mapping)
108 : {
109 0 : if (vma->vm_flags & VM_SHARED)
110 : mapping_unmap_writable(mapping);
111 :
112 0 : flush_dcache_mmap_lock(mapping);
113 0 : vma_interval_tree_remove(vma, &mapping->i_mmap);
114 0 : flush_dcache_mmap_unlock(mapping);
115 : }
116 :
117 : /*
118 : * Unlink a file-based vm structure from its interval tree, to hide
119 : * vma from rmap and vmtruncate before freeing its page tables.
120 : */
121 0 : void unlink_file_vma(struct vm_area_struct *vma)
122 : {
123 0 : struct file *file = vma->vm_file;
124 :
125 0 : if (file) {
126 0 : struct address_space *mapping = file->f_mapping;
127 0 : i_mmap_lock_write(mapping);
128 0 : __remove_shared_vm_struct(vma, file, mapping);
129 : i_mmap_unlock_write(mapping);
130 : }
131 0 : }
132 :
133 : /*
134 : * Close a vm structure and free it.
135 : */
136 0 : static void remove_vma(struct vm_area_struct *vma)
137 : {
138 : might_sleep();
139 0 : if (vma->vm_ops && vma->vm_ops->close)
140 0 : vma->vm_ops->close(vma);
141 0 : if (vma->vm_file)
142 0 : fput(vma->vm_file);
143 0 : mpol_put(vma_policy(vma));
144 0 : vm_area_free(vma);
145 0 : }
146 :
147 : static inline struct vm_area_struct *vma_prev_limit(struct vma_iterator *vmi,
148 : unsigned long min)
149 : {
150 0 : return mas_prev(&vmi->mas, min);
151 : }
152 :
153 0 : static inline int vma_iter_clear_gfp(struct vma_iterator *vmi,
154 : unsigned long start, unsigned long end, gfp_t gfp)
155 : {
156 0 : vmi->mas.index = start;
157 0 : vmi->mas.last = end - 1;
158 0 : mas_store_gfp(&vmi->mas, NULL, gfp);
159 0 : if (unlikely(mas_is_err(&vmi->mas)))
160 : return -ENOMEM;
161 :
162 0 : return 0;
163 : }
164 :
165 : /*
166 : * check_brk_limits() - Use platform specific check of range & verify mlock
167 : * limits.
168 : * @addr: The address to check
169 : * @len: The size of increase.
170 : *
171 : * Return: 0 on success.
172 : */
173 0 : static int check_brk_limits(unsigned long addr, unsigned long len)
174 : {
175 : unsigned long mapped_addr;
176 :
177 0 : mapped_addr = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED);
178 0 : if (IS_ERR_VALUE(mapped_addr))
179 0 : return mapped_addr;
180 :
181 0 : return mlock_future_check(current->mm, current->mm->def_flags, len);
182 : }
183 : static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *brkvma,
184 : unsigned long addr, unsigned long request, unsigned long flags);
185 0 : SYSCALL_DEFINE1(brk, unsigned long, brk)
186 : {
187 : unsigned long newbrk, oldbrk, origbrk;
188 0 : struct mm_struct *mm = current->mm;
189 0 : struct vm_area_struct *brkvma, *next = NULL;
190 : unsigned long min_brk;
191 : bool populate;
192 0 : bool downgraded = false;
193 0 : LIST_HEAD(uf);
194 : struct vma_iterator vmi;
195 :
196 0 : if (mmap_write_lock_killable(mm))
197 : return -EINTR;
198 :
199 0 : origbrk = mm->brk;
200 :
201 : #ifdef CONFIG_COMPAT_BRK
202 : /*
203 : * CONFIG_COMPAT_BRK can still be overridden by setting
204 : * randomize_va_space to 2, which will still cause mm->start_brk
205 : * to be arbitrarily shifted
206 : */
207 0 : if (current->brk_randomized)
208 0 : min_brk = mm->start_brk;
209 : else
210 0 : min_brk = mm->end_data;
211 : #else
212 : min_brk = mm->start_brk;
213 : #endif
214 0 : if (brk < min_brk)
215 : goto out;
216 :
217 : /*
218 : * Check against rlimit here. If this check is done later after the test
219 : * of oldbrk with newbrk then it can escape the test and let the data
220 : * segment grow beyond its set limit the in case where the limit is
221 : * not page aligned -Ram Gupta
222 : */
223 0 : if (check_data_rlimit(rlimit(RLIMIT_DATA), brk, mm->start_brk,
224 : mm->end_data, mm->start_data))
225 : goto out;
226 :
227 0 : newbrk = PAGE_ALIGN(brk);
228 0 : oldbrk = PAGE_ALIGN(mm->brk);
229 0 : if (oldbrk == newbrk) {
230 0 : mm->brk = brk;
231 0 : goto success;
232 : }
233 :
234 : /*
235 : * Always allow shrinking brk.
236 : * do_vma_munmap() may downgrade mmap_lock to read.
237 : */
238 0 : if (brk <= mm->brk) {
239 : int ret;
240 :
241 : /* Search one past newbrk */
242 0 : vma_iter_init(&vmi, mm, newbrk);
243 0 : brkvma = vma_find(&vmi, oldbrk);
244 0 : if (!brkvma || brkvma->vm_start >= oldbrk)
245 : goto out; /* mapping intersects with an existing non-brk vma. */
246 : /*
247 : * mm->brk must be protected by write mmap_lock.
248 : * do_vma_munmap() may downgrade the lock, so update it
249 : * before calling do_vma_munmap().
250 : */
251 0 : mm->brk = brk;
252 0 : ret = do_vma_munmap(&vmi, brkvma, newbrk, oldbrk, &uf, true);
253 0 : if (ret == 1) {
254 : downgraded = true;
255 : goto success;
256 0 : } else if (!ret)
257 : goto success;
258 :
259 0 : mm->brk = origbrk;
260 0 : goto out;
261 : }
262 :
263 0 : if (check_brk_limits(oldbrk, newbrk - oldbrk))
264 : goto out;
265 :
266 : /*
267 : * Only check if the next VMA is within the stack_guard_gap of the
268 : * expansion area
269 : */
270 0 : vma_iter_init(&vmi, mm, oldbrk);
271 0 : next = vma_find(&vmi, newbrk + PAGE_SIZE + stack_guard_gap);
272 0 : if (next && newbrk + PAGE_SIZE > vm_start_gap(next))
273 : goto out;
274 :
275 0 : brkvma = vma_prev_limit(&vmi, mm->start_brk);
276 : /* Ok, looks good - let it rip. */
277 0 : if (do_brk_flags(&vmi, brkvma, oldbrk, newbrk - oldbrk, 0) < 0)
278 : goto out;
279 :
280 0 : mm->brk = brk;
281 :
282 : success:
283 0 : populate = newbrk > oldbrk && (mm->def_flags & VM_LOCKED) != 0;
284 0 : if (downgraded)
285 : mmap_read_unlock(mm);
286 : else
287 : mmap_write_unlock(mm);
288 0 : userfaultfd_unmap_complete(mm, &uf);
289 0 : if (populate)
290 0 : mm_populate(oldbrk, newbrk - oldbrk);
291 0 : return brk;
292 :
293 : out:
294 0 : mmap_write_unlock(mm);
295 0 : return origbrk;
296 : }
297 :
298 : #if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
299 : extern void mt_validate(struct maple_tree *mt);
300 : extern void mt_dump(const struct maple_tree *mt);
301 :
302 : /* Validate the maple tree */
303 : static void validate_mm_mt(struct mm_struct *mm)
304 : {
305 : struct maple_tree *mt = &mm->mm_mt;
306 : struct vm_area_struct *vma_mt;
307 :
308 : MA_STATE(mas, mt, 0, 0);
309 :
310 : mt_validate(&mm->mm_mt);
311 : mas_for_each(&mas, vma_mt, ULONG_MAX) {
312 : if ((vma_mt->vm_start != mas.index) ||
313 : (vma_mt->vm_end - 1 != mas.last)) {
314 : pr_emerg("issue in %s\n", current->comm);
315 : dump_stack();
316 : dump_vma(vma_mt);
317 : pr_emerg("mt piv: %p %lu - %lu\n", vma_mt,
318 : mas.index, mas.last);
319 : pr_emerg("mt vma: %p %lu - %lu\n", vma_mt,
320 : vma_mt->vm_start, vma_mt->vm_end);
321 :
322 : mt_dump(mas.tree);
323 : if (vma_mt->vm_end != mas.last + 1) {
324 : pr_err("vma: %p vma_mt %lu-%lu\tmt %lu-%lu\n",
325 : mm, vma_mt->vm_start, vma_mt->vm_end,
326 : mas.index, mas.last);
327 : mt_dump(mas.tree);
328 : }
329 : VM_BUG_ON_MM(vma_mt->vm_end != mas.last + 1, mm);
330 : if (vma_mt->vm_start != mas.index) {
331 : pr_err("vma: %p vma_mt %p %lu - %lu doesn't match\n",
332 : mm, vma_mt, vma_mt->vm_start, vma_mt->vm_end);
333 : mt_dump(mas.tree);
334 : }
335 : VM_BUG_ON_MM(vma_mt->vm_start != mas.index, mm);
336 : }
337 : }
338 : }
339 :
340 : static void validate_mm(struct mm_struct *mm)
341 : {
342 : int bug = 0;
343 : int i = 0;
344 : struct vm_area_struct *vma;
345 : MA_STATE(mas, &mm->mm_mt, 0, 0);
346 :
347 : validate_mm_mt(mm);
348 :
349 : mas_for_each(&mas, vma, ULONG_MAX) {
350 : #ifdef CONFIG_DEBUG_VM_RB
351 : struct anon_vma *anon_vma = vma->anon_vma;
352 : struct anon_vma_chain *avc;
353 :
354 : if (anon_vma) {
355 : anon_vma_lock_read(anon_vma);
356 : list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
357 : anon_vma_interval_tree_verify(avc);
358 : anon_vma_unlock_read(anon_vma);
359 : }
360 : #endif
361 : i++;
362 : }
363 : if (i != mm->map_count) {
364 : pr_emerg("map_count %d mas_for_each %d\n", mm->map_count, i);
365 : bug = 1;
366 : }
367 : VM_BUG_ON_MM(bug, mm);
368 : }
369 :
370 : #else /* !CONFIG_DEBUG_VM_MAPLE_TREE */
371 : #define validate_mm_mt(root) do { } while (0)
372 : #define validate_mm(mm) do { } while (0)
373 : #endif /* CONFIG_DEBUG_VM_MAPLE_TREE */
374 :
375 : /*
376 : * vma has some anon_vma assigned, and is already inserted on that
377 : * anon_vma's interval trees.
378 : *
379 : * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the
380 : * vma must be removed from the anon_vma's interval trees using
381 : * anon_vma_interval_tree_pre_update_vma().
382 : *
383 : * After the update, the vma will be reinserted using
384 : * anon_vma_interval_tree_post_update_vma().
385 : *
386 : * The entire update must be protected by exclusive mmap_lock and by
387 : * the root anon_vma's mutex.
388 : */
389 : static inline void
390 0 : anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma)
391 : {
392 : struct anon_vma_chain *avc;
393 :
394 0 : list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
395 0 : anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root);
396 0 : }
397 :
398 : static inline void
399 0 : anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma)
400 : {
401 : struct anon_vma_chain *avc;
402 :
403 0 : list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
404 0 : anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root);
405 0 : }
406 :
407 0 : static unsigned long count_vma_pages_range(struct mm_struct *mm,
408 : unsigned long addr, unsigned long end)
409 : {
410 0 : VMA_ITERATOR(vmi, mm, addr);
411 : struct vm_area_struct *vma;
412 0 : unsigned long nr_pages = 0;
413 :
414 0 : for_each_vma_range(vmi, vma, end) {
415 0 : unsigned long vm_start = max(addr, vma->vm_start);
416 0 : unsigned long vm_end = min(end, vma->vm_end);
417 :
418 0 : nr_pages += PHYS_PFN(vm_end - vm_start);
419 : }
420 :
421 0 : return nr_pages;
422 : }
423 :
424 : static void __vma_link_file(struct vm_area_struct *vma,
425 : struct address_space *mapping)
426 : {
427 0 : if (vma->vm_flags & VM_SHARED)
428 : mapping_allow_writable(mapping);
429 :
430 0 : flush_dcache_mmap_lock(mapping);
431 0 : vma_interval_tree_insert(vma, &mapping->i_mmap);
432 0 : flush_dcache_mmap_unlock(mapping);
433 : }
434 :
435 0 : static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma)
436 : {
437 0 : VMA_ITERATOR(vmi, mm, 0);
438 0 : struct address_space *mapping = NULL;
439 :
440 0 : if (vma_iter_prealloc(&vmi))
441 : return -ENOMEM;
442 :
443 0 : if (vma->vm_file) {
444 0 : mapping = vma->vm_file->f_mapping;
445 : i_mmap_lock_write(mapping);
446 : }
447 :
448 0 : vma_iter_store(&vmi, vma);
449 :
450 0 : if (mapping) {
451 0 : __vma_link_file(vma, mapping);
452 : i_mmap_unlock_write(mapping);
453 : }
454 :
455 0 : mm->map_count++;
456 : validate_mm(mm);
457 0 : return 0;
458 : }
459 :
460 : /*
461 : * init_multi_vma_prep() - Initializer for struct vma_prepare
462 : * @vp: The vma_prepare struct
463 : * @vma: The vma that will be altered once locked
464 : * @next: The next vma if it is to be adjusted
465 : * @remove: The first vma to be removed
466 : * @remove2: The second vma to be removed
467 : */
468 0 : static inline void init_multi_vma_prep(struct vma_prepare *vp,
469 : struct vm_area_struct *vma, struct vm_area_struct *next,
470 : struct vm_area_struct *remove, struct vm_area_struct *remove2)
471 : {
472 0 : memset(vp, 0, sizeof(struct vma_prepare));
473 0 : vp->vma = vma;
474 0 : vp->anon_vma = vma->anon_vma;
475 0 : vp->remove = remove;
476 0 : vp->remove2 = remove2;
477 0 : vp->adj_next = next;
478 0 : if (!vp->anon_vma && next)
479 0 : vp->anon_vma = next->anon_vma;
480 :
481 0 : vp->file = vma->vm_file;
482 0 : if (vp->file)
483 0 : vp->mapping = vma->vm_file->f_mapping;
484 :
485 0 : }
486 :
487 : /*
488 : * init_vma_prep() - Initializer wrapper for vma_prepare struct
489 : * @vp: The vma_prepare struct
490 : * @vma: The vma that will be altered once locked
491 : */
492 : static inline void init_vma_prep(struct vma_prepare *vp,
493 : struct vm_area_struct *vma)
494 : {
495 0 : init_multi_vma_prep(vp, vma, NULL, NULL, NULL);
496 : }
497 :
498 :
499 : /*
500 : * vma_prepare() - Helper function for handling locking VMAs prior to altering
501 : * @vp: The initialized vma_prepare struct
502 : */
503 0 : static inline void vma_prepare(struct vma_prepare *vp)
504 : {
505 0 : if (vp->file) {
506 0 : uprobe_munmap(vp->vma, vp->vma->vm_start, vp->vma->vm_end);
507 :
508 0 : if (vp->adj_next)
509 : uprobe_munmap(vp->adj_next, vp->adj_next->vm_start,
510 : vp->adj_next->vm_end);
511 :
512 0 : i_mmap_lock_write(vp->mapping);
513 0 : if (vp->insert && vp->insert->vm_file) {
514 : /*
515 : * Put into interval tree now, so instantiated pages
516 : * are visible to arm/parisc __flush_dcache_page
517 : * throughout; but we cannot insert into address
518 : * space until vma start or end is updated.
519 : */
520 0 : __vma_link_file(vp->insert,
521 : vp->insert->vm_file->f_mapping);
522 : }
523 : }
524 :
525 0 : if (vp->anon_vma) {
526 0 : anon_vma_lock_write(vp->anon_vma);
527 0 : anon_vma_interval_tree_pre_update_vma(vp->vma);
528 0 : if (vp->adj_next)
529 0 : anon_vma_interval_tree_pre_update_vma(vp->adj_next);
530 : }
531 :
532 0 : if (vp->file) {
533 0 : flush_dcache_mmap_lock(vp->mapping);
534 0 : vma_interval_tree_remove(vp->vma, &vp->mapping->i_mmap);
535 0 : if (vp->adj_next)
536 0 : vma_interval_tree_remove(vp->adj_next,
537 0 : &vp->mapping->i_mmap);
538 : }
539 :
540 0 : }
541 :
542 : /*
543 : * vma_complete- Helper function for handling the unlocking after altering VMAs,
544 : * or for inserting a VMA.
545 : *
546 : * @vp: The vma_prepare struct
547 : * @vmi: The vma iterator
548 : * @mm: The mm_struct
549 : */
550 0 : static inline void vma_complete(struct vma_prepare *vp,
551 : struct vma_iterator *vmi, struct mm_struct *mm)
552 : {
553 0 : if (vp->file) {
554 0 : if (vp->adj_next)
555 0 : vma_interval_tree_insert(vp->adj_next,
556 0 : &vp->mapping->i_mmap);
557 0 : vma_interval_tree_insert(vp->vma, &vp->mapping->i_mmap);
558 0 : flush_dcache_mmap_unlock(vp->mapping);
559 : }
560 :
561 0 : if (vp->remove && vp->file) {
562 0 : __remove_shared_vm_struct(vp->remove, vp->file, vp->mapping);
563 0 : if (vp->remove2)
564 0 : __remove_shared_vm_struct(vp->remove2, vp->file,
565 : vp->mapping);
566 0 : } else if (vp->insert) {
567 : /*
568 : * split_vma has split insert from vma, and needs
569 : * us to insert it before dropping the locks
570 : * (it may either follow vma or precede it).
571 : */
572 0 : vma_iter_store(vmi, vp->insert);
573 0 : mm->map_count++;
574 : }
575 :
576 0 : if (vp->anon_vma) {
577 0 : anon_vma_interval_tree_post_update_vma(vp->vma);
578 0 : if (vp->adj_next)
579 0 : anon_vma_interval_tree_post_update_vma(vp->adj_next);
580 0 : anon_vma_unlock_write(vp->anon_vma);
581 : }
582 :
583 0 : if (vp->file) {
584 0 : i_mmap_unlock_write(vp->mapping);
585 0 : uprobe_mmap(vp->vma);
586 :
587 : if (vp->adj_next)
588 : uprobe_mmap(vp->adj_next);
589 : }
590 :
591 0 : if (vp->remove) {
592 : again:
593 0 : if (vp->file) {
594 0 : uprobe_munmap(vp->remove, vp->remove->vm_start,
595 0 : vp->remove->vm_end);
596 0 : fput(vp->file);
597 : }
598 0 : if (vp->remove->anon_vma)
599 0 : anon_vma_merge(vp->vma, vp->remove);
600 0 : mm->map_count--;
601 0 : mpol_put(vma_policy(vp->remove));
602 0 : if (!vp->remove2)
603 0 : WARN_ON_ONCE(vp->vma->vm_end < vp->remove->vm_end);
604 0 : vm_area_free(vp->remove);
605 :
606 : /*
607 : * In mprotect's case 6 (see comments on vma_merge),
608 : * we must remove the one after next as well.
609 : */
610 0 : if (vp->remove2) {
611 0 : vp->remove = vp->remove2;
612 0 : vp->remove2 = NULL;
613 0 : goto again;
614 : }
615 : }
616 : if (vp->insert && vp->file)
617 : uprobe_mmap(vp->insert);
618 0 : }
619 :
620 : /*
621 : * dup_anon_vma() - Helper function to duplicate anon_vma
622 : * @dst: The destination VMA
623 : * @src: The source VMA
624 : *
625 : * Returns: 0 on success.
626 : */
627 : static inline int dup_anon_vma(struct vm_area_struct *dst,
628 : struct vm_area_struct *src)
629 : {
630 : /*
631 : * Easily overlooked: when mprotect shifts the boundary, make sure the
632 : * expanding vma has anon_vma set if the shrinking vma had, to cover any
633 : * anon pages imported.
634 : */
635 0 : if (src->anon_vma && !dst->anon_vma) {
636 0 : dst->anon_vma = src->anon_vma;
637 0 : return anon_vma_clone(dst, src);
638 : }
639 :
640 : return 0;
641 : }
642 :
643 : /*
644 : * vma_expand - Expand an existing VMA
645 : *
646 : * @vmi: The vma iterator
647 : * @vma: The vma to expand
648 : * @start: The start of the vma
649 : * @end: The exclusive end of the vma
650 : * @pgoff: The page offset of vma
651 : * @next: The current of next vma.
652 : *
653 : * Expand @vma to @start and @end. Can expand off the start and end. Will
654 : * expand over @next if it's different from @vma and @end == @next->vm_end.
655 : * Checking if the @vma can expand and merge with @next needs to be handled by
656 : * the caller.
657 : *
658 : * Returns: 0 on success
659 : */
660 0 : int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
661 : unsigned long start, unsigned long end, pgoff_t pgoff,
662 : struct vm_area_struct *next)
663 : {
664 0 : bool remove_next = false;
665 : struct vma_prepare vp;
666 :
667 0 : if (next && (vma != next) && (end == next->vm_end)) {
668 : int ret;
669 :
670 0 : remove_next = true;
671 0 : ret = dup_anon_vma(vma, next);
672 0 : if (ret)
673 : return ret;
674 : }
675 :
676 0 : init_multi_vma_prep(&vp, vma, NULL, remove_next ? next : NULL, NULL);
677 : /* Not merging but overwriting any part of next is not handled. */
678 : VM_WARN_ON(next && !vp.remove &&
679 : next != vma && end > next->vm_start);
680 : /* Only handles expanding */
681 : VM_WARN_ON(vma->vm_start < start || vma->vm_end > end);
682 :
683 0 : if (vma_iter_prealloc(vmi))
684 : goto nomem;
685 :
686 0 : vma_adjust_trans_huge(vma, start, end, 0);
687 : /* VMA iterator points to previous, so set to start if necessary */
688 0 : if (vma_iter_addr(vmi) != start)
689 : vma_iter_set(vmi, start);
690 :
691 0 : vma_prepare(&vp);
692 0 : vma->vm_start = start;
693 0 : vma->vm_end = end;
694 0 : vma->vm_pgoff = pgoff;
695 : /* Note: mas must be pointing to the expanding VMA */
696 0 : vma_iter_store(vmi, vma);
697 :
698 0 : vma_complete(&vp, vmi, vma->vm_mm);
699 : validate_mm(vma->vm_mm);
700 0 : return 0;
701 :
702 : nomem:
703 : return -ENOMEM;
704 : }
705 :
706 : /*
707 : * vma_shrink() - Reduce an existing VMAs memory area
708 : * @vmi: The vma iterator
709 : * @vma: The VMA to modify
710 : * @start: The new start
711 : * @end: The new end
712 : *
713 : * Returns: 0 on success, -ENOMEM otherwise
714 : */
715 0 : int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,
716 : unsigned long start, unsigned long end, pgoff_t pgoff)
717 : {
718 : struct vma_prepare vp;
719 :
720 0 : WARN_ON((vma->vm_start != start) && (vma->vm_end != end));
721 :
722 0 : if (vma_iter_prealloc(vmi))
723 : return -ENOMEM;
724 :
725 0 : init_vma_prep(&vp, vma);
726 0 : vma_adjust_trans_huge(vma, start, end, 0);
727 0 : vma_prepare(&vp);
728 :
729 0 : if (vma->vm_start < start)
730 0 : vma_iter_clear(vmi, vma->vm_start, start);
731 :
732 0 : if (vma->vm_end > end)
733 0 : vma_iter_clear(vmi, end, vma->vm_end);
734 :
735 0 : vma->vm_start = start;
736 0 : vma->vm_end = end;
737 0 : vma->vm_pgoff = pgoff;
738 0 : vma_complete(&vp, vmi, vma->vm_mm);
739 : validate_mm(vma->vm_mm);
740 0 : return 0;
741 : }
742 :
743 : /*
744 : * If the vma has a ->close operation then the driver probably needs to release
745 : * per-vma resources, so we don't attempt to merge those.
746 : */
747 : static inline int is_mergeable_vma(struct vm_area_struct *vma,
748 : struct file *file, unsigned long vm_flags,
749 : struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
750 : struct anon_vma_name *anon_name)
751 : {
752 : /*
753 : * VM_SOFTDIRTY should not prevent from VMA merging, if we
754 : * match the flags but dirty bit -- the caller should mark
755 : * merged VMA as dirty. If dirty bit won't be excluded from
756 : * comparison, we increase pressure on the memory system forcing
757 : * the kernel to generate new VMAs when old one could be
758 : * extended instead.
759 : */
760 0 : if ((vma->vm_flags ^ vm_flags) & ~VM_SOFTDIRTY)
761 : return 0;
762 0 : if (vma->vm_file != file)
763 : return 0;
764 0 : if (vma->vm_ops && vma->vm_ops->close)
765 : return 0;
766 0 : if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx))
767 : return 0;
768 0 : if (!anon_vma_name_eq(anon_vma_name(vma), anon_name))
769 : return 0;
770 : return 1;
771 : }
772 :
773 : static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
774 : struct anon_vma *anon_vma2,
775 : struct vm_area_struct *vma)
776 : {
777 : /*
778 : * The list_is_singular() test is to avoid merging VMA cloned from
779 : * parents. This can improve scalability caused by anon_vma lock.
780 : */
781 0 : if ((!anon_vma1 || !anon_vma2) && (!vma ||
782 0 : list_is_singular(&vma->anon_vma_chain)))
783 : return 1;
784 0 : return anon_vma1 == anon_vma2;
785 : }
786 :
787 : /*
788 : * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
789 : * in front of (at a lower virtual address and file offset than) the vma.
790 : *
791 : * We cannot merge two vmas if they have differently assigned (non-NULL)
792 : * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
793 : *
794 : * We don't check here for the merged mmap wrapping around the end of pagecache
795 : * indices (16TB on ia32) because do_mmap() does not permit mmap's which
796 : * wrap, nor mmaps which cover the final page at index -1UL.
797 : */
798 : static int
799 0 : can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
800 : struct anon_vma *anon_vma, struct file *file,
801 : pgoff_t vm_pgoff,
802 : struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
803 : struct anon_vma_name *anon_name)
804 : {
805 0 : if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) &&
806 0 : is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
807 0 : if (vma->vm_pgoff == vm_pgoff)
808 : return 1;
809 : }
810 : return 0;
811 : }
812 :
813 : /*
814 : * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
815 : * beyond (at a higher virtual address and file offset than) the vma.
816 : *
817 : * We cannot merge two vmas if they have differently assigned (non-NULL)
818 : * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
819 : */
820 : static int
821 0 : can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
822 : struct anon_vma *anon_vma, struct file *file,
823 : pgoff_t vm_pgoff,
824 : struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
825 : struct anon_vma_name *anon_name)
826 : {
827 0 : if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) &&
828 0 : is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
829 : pgoff_t vm_pglen;
830 0 : vm_pglen = vma_pages(vma);
831 0 : if (vma->vm_pgoff + vm_pglen == vm_pgoff)
832 : return 1;
833 : }
834 : return 0;
835 : }
836 :
837 : /*
838 : * Given a mapping request (addr,end,vm_flags,file,pgoff,anon_name),
839 : * figure out whether that can be merged with its predecessor or its
840 : * successor. Or both (it neatly fills a hole).
841 : *
842 : * In most cases - when called for mmap, brk or mremap - [addr,end) is
843 : * certain not to be mapped by the time vma_merge is called; but when
844 : * called for mprotect, it is certain to be already mapped (either at
845 : * an offset within prev, or at the start of next), and the flags of
846 : * this area are about to be changed to vm_flags - and the no-change
847 : * case has already been eliminated.
848 : *
849 : * The following mprotect cases have to be considered, where AAAA is
850 : * the area passed down from mprotect_fixup, never extending beyond one
851 : * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
852 : *
853 : * AAAA AAAA AAAA
854 : * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN
855 : * cannot merge might become might become
856 : * PPNNNNNNNNNN PPPPPPPPPPNN
857 : * mmap, brk or case 4 below case 5 below
858 : * mremap move:
859 : * AAAA AAAA
860 : * PPPP NNNN PPPPNNNNXXXX
861 : * might become might become
862 : * PPPPPPPPPPPP 1 or PPPPPPPPPPPP 6 or
863 : * PPPPPPPPNNNN 2 or PPPPPPPPXXXX 7 or
864 : * PPPPNNNNNNNN 3 PPPPXXXXXXXX 8
865 : *
866 : * It is important for case 8 that the vma NNNN overlapping the
867 : * region AAAA is never going to extended over XXXX. Instead XXXX must
868 : * be extended in region AAAA and NNNN must be removed. This way in
869 : * all cases where vma_merge succeeds, the moment vma_merge drops the
870 : * rmap_locks, the properties of the merged vma will be already
871 : * correct for the whole merged range. Some of those properties like
872 : * vm_page_prot/vm_flags may be accessed by rmap_walks and they must
873 : * be correct for the whole merged range immediately after the
874 : * rmap_locks are released. Otherwise if XXXX would be removed and
875 : * NNNN would be extended over the XXXX range, remove_migration_ptes
876 : * or other rmap walkers (if working on addresses beyond the "end"
877 : * parameter) may establish ptes with the wrong permissions of NNNN
878 : * instead of the right permissions of XXXX.
879 : *
880 : * In the code below:
881 : * PPPP is represented by *prev
882 : * NNNN is represented by *mid (and possibly equal to *next)
883 : * XXXX is represented by *next or not represented at all.
884 : * AAAA is not represented - it will be merged or the function will return NULL
885 : */
886 0 : struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm,
887 : struct vm_area_struct *prev, unsigned long addr,
888 : unsigned long end, unsigned long vm_flags,
889 : struct anon_vma *anon_vma, struct file *file,
890 : pgoff_t pgoff, struct mempolicy *policy,
891 : struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
892 : struct anon_vma_name *anon_name)
893 : {
894 0 : pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
895 : pgoff_t vma_pgoff;
896 0 : struct vm_area_struct *mid, *next, *res = NULL;
897 : struct vm_area_struct *vma, *adjust, *remove, *remove2;
898 0 : int err = -1;
899 0 : bool merge_prev = false;
900 0 : bool merge_next = false;
901 0 : bool vma_expanded = false;
902 : struct vma_prepare vp;
903 0 : unsigned long vma_end = end;
904 0 : long adj_next = 0;
905 0 : unsigned long vma_start = addr;
906 :
907 : validate_mm(mm);
908 : /*
909 : * We later require that vma->vm_flags == vm_flags,
910 : * so this tests vma->vm_flags & VM_SPECIAL, too.
911 : */
912 0 : if (vm_flags & VM_SPECIAL)
913 : return NULL;
914 :
915 0 : next = find_vma(mm, prev ? prev->vm_end : 0);
916 0 : mid = next;
917 0 : if (next && next->vm_end == end) /* cases 6, 7, 8 */
918 0 : next = find_vma(mm, next->vm_end);
919 :
920 : /* verify some invariant that must be enforced by the caller */
921 : VM_WARN_ON(prev && addr <= prev->vm_start);
922 : VM_WARN_ON(mid && end > mid->vm_end);
923 : VM_WARN_ON(addr >= end);
924 :
925 0 : if (prev) {
926 0 : res = prev;
927 0 : vma = prev;
928 0 : vma_start = prev->vm_start;
929 0 : vma_pgoff = prev->vm_pgoff;
930 : /* Can we merge the predecessor? */
931 0 : if (prev->vm_end == addr && mpol_equal(vma_policy(prev), policy)
932 0 : && can_vma_merge_after(prev, vm_flags, anon_vma, file,
933 : pgoff, vm_userfaultfd_ctx, anon_name)) {
934 0 : merge_prev = true;
935 : vma_prev(vmi);
936 : }
937 : }
938 : /* Can we merge the successor? */
939 0 : if (next && end == next->vm_start &&
940 0 : mpol_equal(policy, vma_policy(next)) &&
941 0 : can_vma_merge_before(next, vm_flags,
942 : anon_vma, file, pgoff+pglen,
943 : vm_userfaultfd_ctx, anon_name)) {
944 0 : merge_next = true;
945 : }
946 :
947 0 : remove = remove2 = adjust = NULL;
948 : /* Can we merge both the predecessor and the successor? */
949 0 : if (merge_prev && merge_next &&
950 0 : is_mergeable_anon_vma(prev->anon_vma, next->anon_vma, NULL)) {
951 0 : remove = mid; /* case 1 */
952 0 : vma_end = next->vm_end;
953 0 : err = dup_anon_vma(res, remove);
954 0 : if (mid != next) { /* case 6 */
955 0 : remove2 = next;
956 0 : if (!remove->anon_vma)
957 : err = dup_anon_vma(res, remove2);
958 : }
959 0 : } else if (merge_prev) {
960 0 : err = 0; /* case 2 */
961 0 : if (mid && end > mid->vm_start) {
962 0 : err = dup_anon_vma(res, mid);
963 0 : if (end == mid->vm_end) { /* case 7 */
964 : remove = mid;
965 : } else { /* case 5 */
966 0 : adjust = mid;
967 0 : adj_next = (end - mid->vm_start);
968 : }
969 : }
970 0 : } else if (merge_next) {
971 0 : res = next;
972 0 : if (prev && addr < prev->vm_end) { /* case 4 */
973 0 : vma_end = addr;
974 0 : adjust = mid;
975 0 : adj_next = -(vma->vm_end - addr);
976 : err = dup_anon_vma(adjust, prev);
977 : } else {
978 0 : vma = next; /* case 3 */
979 0 : vma_start = addr;
980 0 : vma_end = next->vm_end;
981 0 : vma_pgoff = mid->vm_pgoff;
982 0 : err = 0;
983 0 : if (mid != next) { /* case 8 */
984 0 : remove = mid;
985 : err = dup_anon_vma(res, remove);
986 : }
987 : }
988 : }
989 :
990 : /* Cannot merge or error in anon_vma clone */
991 0 : if (err)
992 : return NULL;
993 :
994 0 : if (vma_iter_prealloc(vmi))
995 : return NULL;
996 :
997 0 : vma_adjust_trans_huge(vma, vma_start, vma_end, adj_next);
998 0 : init_multi_vma_prep(&vp, vma, adjust, remove, remove2);
999 : VM_WARN_ON(vp.anon_vma && adjust && adjust->anon_vma &&
1000 : vp.anon_vma != adjust->anon_vma);
1001 :
1002 0 : vma_prepare(&vp);
1003 0 : if (vma_start < vma->vm_start || vma_end > vma->vm_end)
1004 0 : vma_expanded = true;
1005 :
1006 0 : vma->vm_start = vma_start;
1007 0 : vma->vm_end = vma_end;
1008 0 : vma->vm_pgoff = vma_pgoff;
1009 :
1010 0 : if (vma_expanded)
1011 0 : vma_iter_store(vmi, vma);
1012 :
1013 0 : if (adj_next) {
1014 0 : adjust->vm_start += adj_next;
1015 0 : adjust->vm_pgoff += adj_next >> PAGE_SHIFT;
1016 0 : if (adj_next < 0) {
1017 0 : WARN_ON(vma_expanded);
1018 0 : vma_iter_store(vmi, next);
1019 : }
1020 : }
1021 :
1022 0 : vma_complete(&vp, vmi, mm);
1023 0 : vma_iter_free(vmi);
1024 : validate_mm(mm);
1025 0 : khugepaged_enter_vma(res, vm_flags);
1026 :
1027 0 : return res;
1028 : }
1029 :
1030 : /*
1031 : * Rough compatibility check to quickly see if it's even worth looking
1032 : * at sharing an anon_vma.
1033 : *
1034 : * They need to have the same vm_file, and the flags can only differ
1035 : * in things that mprotect may change.
1036 : *
1037 : * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that
1038 : * we can merge the two vma's. For example, we refuse to merge a vma if
1039 : * there is a vm_ops->close() function, because that indicates that the
1040 : * driver is doing some kind of reference counting. But that doesn't
1041 : * really matter for the anon_vma sharing case.
1042 : */
1043 : static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b)
1044 : {
1045 0 : return a->vm_end == b->vm_start &&
1046 0 : mpol_equal(vma_policy(a), vma_policy(b)) &&
1047 0 : a->vm_file == b->vm_file &&
1048 0 : !((a->vm_flags ^ b->vm_flags) & ~(VM_ACCESS_FLAGS | VM_SOFTDIRTY)) &&
1049 0 : b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT);
1050 : }
1051 :
1052 : /*
1053 : * Do some basic sanity checking to see if we can re-use the anon_vma
1054 : * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be
1055 : * the same as 'old', the other will be the new one that is trying
1056 : * to share the anon_vma.
1057 : *
1058 : * NOTE! This runs with mmap_lock held for reading, so it is possible that
1059 : * the anon_vma of 'old' is concurrently in the process of being set up
1060 : * by another page fault trying to merge _that_. But that's ok: if it
1061 : * is being set up, that automatically means that it will be a singleton
1062 : * acceptable for merging, so we can do all of this optimistically. But
1063 : * we do that READ_ONCE() to make sure that we never re-load the pointer.
1064 : *
1065 : * IOW: that the "list_is_singular()" test on the anon_vma_chain only
1066 : * matters for the 'stable anon_vma' case (ie the thing we want to avoid
1067 : * is to return an anon_vma that is "complex" due to having gone through
1068 : * a fork).
1069 : *
1070 : * We also make sure that the two vma's are compatible (adjacent,
1071 : * and with the same memory policies). That's all stable, even with just
1072 : * a read lock on the mmap_lock.
1073 : */
1074 0 : static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b)
1075 : {
1076 0 : if (anon_vma_compatible(a, b)) {
1077 0 : struct anon_vma *anon_vma = READ_ONCE(old->anon_vma);
1078 :
1079 0 : if (anon_vma && list_is_singular(&old->anon_vma_chain))
1080 : return anon_vma;
1081 : }
1082 : return NULL;
1083 : }
1084 :
1085 : /*
1086 : * find_mergeable_anon_vma is used by anon_vma_prepare, to check
1087 : * neighbouring vmas for a suitable anon_vma, before it goes off
1088 : * to allocate a new anon_vma. It checks because a repetitive
1089 : * sequence of mprotects and faults may otherwise lead to distinct
1090 : * anon_vmas being allocated, preventing vma merge in subsequent
1091 : * mprotect.
1092 : */
1093 0 : struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
1094 : {
1095 0 : MA_STATE(mas, &vma->vm_mm->mm_mt, vma->vm_end, vma->vm_end);
1096 0 : struct anon_vma *anon_vma = NULL;
1097 : struct vm_area_struct *prev, *next;
1098 :
1099 : /* Try next first. */
1100 0 : next = mas_walk(&mas);
1101 0 : if (next) {
1102 0 : anon_vma = reusable_anon_vma(next, vma, next);
1103 0 : if (anon_vma)
1104 : return anon_vma;
1105 : }
1106 :
1107 0 : prev = mas_prev(&mas, 0);
1108 : VM_BUG_ON_VMA(prev != vma, vma);
1109 0 : prev = mas_prev(&mas, 0);
1110 : /* Try prev next. */
1111 0 : if (prev)
1112 0 : anon_vma = reusable_anon_vma(prev, prev, vma);
1113 :
1114 : /*
1115 : * We might reach here with anon_vma == NULL if we can't find
1116 : * any reusable anon_vma.
1117 : * There's no absolute need to look only at touching neighbours:
1118 : * we could search further afield for "compatible" anon_vmas.
1119 : * But it would probably just be a waste of time searching,
1120 : * or lead to too many vmas hanging off the same anon_vma.
1121 : * We're trying to allow mprotect remerging later on,
1122 : * not trying to minimize memory used for anon_vmas.
1123 : */
1124 : return anon_vma;
1125 : }
1126 :
1127 : /*
1128 : * If a hint addr is less than mmap_min_addr change hint to be as
1129 : * low as possible but still greater than mmap_min_addr
1130 : */
1131 : static inline unsigned long round_hint_to_min(unsigned long hint)
1132 : {
1133 0 : hint &= PAGE_MASK;
1134 0 : if (((void *)hint != NULL) &&
1135 0 : (hint < mmap_min_addr))
1136 0 : return PAGE_ALIGN(mmap_min_addr);
1137 : return hint;
1138 : }
1139 :
1140 0 : int mlock_future_check(struct mm_struct *mm, unsigned long flags,
1141 : unsigned long len)
1142 : {
1143 : unsigned long locked, lock_limit;
1144 :
1145 : /* mlock MCL_FUTURE? */
1146 0 : if (flags & VM_LOCKED) {
1147 0 : locked = len >> PAGE_SHIFT;
1148 0 : locked += mm->locked_vm;
1149 0 : lock_limit = rlimit(RLIMIT_MEMLOCK);
1150 0 : lock_limit >>= PAGE_SHIFT;
1151 0 : if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1152 : return -EAGAIN;
1153 : }
1154 : return 0;
1155 : }
1156 :
1157 : static inline u64 file_mmap_size_max(struct file *file, struct inode *inode)
1158 : {
1159 0 : if (S_ISREG(inode->i_mode))
1160 : return MAX_LFS_FILESIZE;
1161 :
1162 0 : if (S_ISBLK(inode->i_mode))
1163 : return MAX_LFS_FILESIZE;
1164 :
1165 0 : if (S_ISSOCK(inode->i_mode))
1166 : return MAX_LFS_FILESIZE;
1167 :
1168 : /* Special "we do even unsigned file positions" case */
1169 0 : if (file->f_mode & FMODE_UNSIGNED_OFFSET)
1170 : return 0;
1171 :
1172 : /* Yes, random drivers might want more. But I'm tired of buggy drivers */
1173 : return ULONG_MAX;
1174 : }
1175 :
1176 : static inline bool file_mmap_ok(struct file *file, struct inode *inode,
1177 : unsigned long pgoff, unsigned long len)
1178 : {
1179 0 : u64 maxsize = file_mmap_size_max(file, inode);
1180 :
1181 0 : if (maxsize && len > maxsize)
1182 : return false;
1183 0 : maxsize -= len;
1184 0 : if (pgoff > maxsize >> PAGE_SHIFT)
1185 : return false;
1186 : return true;
1187 : }
1188 :
1189 : /*
1190 : * The caller must write-lock current->mm->mmap_lock.
1191 : */
1192 0 : unsigned long do_mmap(struct file *file, unsigned long addr,
1193 : unsigned long len, unsigned long prot,
1194 : unsigned long flags, unsigned long pgoff,
1195 : unsigned long *populate, struct list_head *uf)
1196 : {
1197 0 : struct mm_struct *mm = current->mm;
1198 : vm_flags_t vm_flags;
1199 0 : int pkey = 0;
1200 :
1201 : validate_mm(mm);
1202 0 : *populate = 0;
1203 :
1204 0 : if (!len)
1205 : return -EINVAL;
1206 :
1207 : /*
1208 : * Does the application expect PROT_READ to imply PROT_EXEC?
1209 : *
1210 : * (the exception is when the underlying filesystem is noexec
1211 : * mounted, in which case we dont add PROT_EXEC.)
1212 : */
1213 0 : if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
1214 0 : if (!(file && path_noexec(&file->f_path)))
1215 0 : prot |= PROT_EXEC;
1216 :
1217 : /* force arch specific MAP_FIXED handling in get_unmapped_area */
1218 0 : if (flags & MAP_FIXED_NOREPLACE)
1219 0 : flags |= MAP_FIXED;
1220 :
1221 0 : if (!(flags & MAP_FIXED))
1222 : addr = round_hint_to_min(addr);
1223 :
1224 : /* Careful about overflows.. */
1225 0 : len = PAGE_ALIGN(len);
1226 0 : if (!len)
1227 : return -ENOMEM;
1228 :
1229 : /* offset overflow? */
1230 0 : if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
1231 : return -EOVERFLOW;
1232 :
1233 : /* Too many mappings? */
1234 0 : if (mm->map_count > sysctl_max_map_count)
1235 : return -ENOMEM;
1236 :
1237 : /* Obtain the address to map to. we verify (or select) it and ensure
1238 : * that it represents a valid section of the address space.
1239 : */
1240 0 : addr = get_unmapped_area(file, addr, len, pgoff, flags);
1241 0 : if (IS_ERR_VALUE(addr))
1242 : return addr;
1243 :
1244 0 : if (flags & MAP_FIXED_NOREPLACE) {
1245 0 : if (find_vma_intersection(mm, addr, addr + len))
1246 : return -EEXIST;
1247 : }
1248 :
1249 : if (prot == PROT_EXEC) {
1250 : pkey = execute_only_pkey(mm);
1251 : if (pkey < 0)
1252 : pkey = 0;
1253 : }
1254 :
1255 : /* Do simple checking here so the lower-level routines won't have
1256 : * to. we assume access permissions have been handled by the open
1257 : * of the memory object, so we don't do any here.
1258 : */
1259 0 : vm_flags = calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) |
1260 0 : mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1261 :
1262 0 : if (flags & MAP_LOCKED)
1263 0 : if (!can_do_mlock())
1264 : return -EPERM;
1265 :
1266 0 : if (mlock_future_check(mm, vm_flags, len))
1267 : return -EAGAIN;
1268 :
1269 0 : if (file) {
1270 0 : struct inode *inode = file_inode(file);
1271 : unsigned long flags_mask;
1272 :
1273 0 : if (!file_mmap_ok(file, inode, pgoff, len))
1274 : return -EOVERFLOW;
1275 :
1276 0 : flags_mask = LEGACY_MAP_MASK | file->f_op->mmap_supported_flags;
1277 :
1278 0 : switch (flags & MAP_TYPE) {
1279 : case MAP_SHARED:
1280 : /*
1281 : * Force use of MAP_SHARED_VALIDATE with non-legacy
1282 : * flags. E.g. MAP_SYNC is dangerous to use with
1283 : * MAP_SHARED as you don't know which consistency model
1284 : * you will get. We silently ignore unsupported flags
1285 : * with MAP_SHARED to preserve backward compatibility.
1286 : */
1287 0 : flags &= LEGACY_MAP_MASK;
1288 : fallthrough;
1289 : case MAP_SHARED_VALIDATE:
1290 0 : if (flags & ~flags_mask)
1291 : return -EOPNOTSUPP;
1292 0 : if (prot & PROT_WRITE) {
1293 0 : if (!(file->f_mode & FMODE_WRITE))
1294 : return -EACCES;
1295 0 : if (IS_SWAPFILE(file->f_mapping->host))
1296 : return -ETXTBSY;
1297 : }
1298 :
1299 : /*
1300 : * Make sure we don't allow writing to an append-only
1301 : * file..
1302 : */
1303 0 : if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
1304 : return -EACCES;
1305 :
1306 0 : vm_flags |= VM_SHARED | VM_MAYSHARE;
1307 0 : if (!(file->f_mode & FMODE_WRITE))
1308 0 : vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
1309 : fallthrough;
1310 : case MAP_PRIVATE:
1311 0 : if (!(file->f_mode & FMODE_READ))
1312 : return -EACCES;
1313 0 : if (path_noexec(&file->f_path)) {
1314 0 : if (vm_flags & VM_EXEC)
1315 : return -EPERM;
1316 0 : vm_flags &= ~VM_MAYEXEC;
1317 : }
1318 :
1319 0 : if (!file->f_op->mmap)
1320 : return -ENODEV;
1321 0 : if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1322 : return -EINVAL;
1323 : break;
1324 :
1325 : default:
1326 : return -EINVAL;
1327 : }
1328 : } else {
1329 0 : switch (flags & MAP_TYPE) {
1330 : case MAP_SHARED:
1331 0 : if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1332 : return -EINVAL;
1333 : /*
1334 : * Ignore pgoff.
1335 : */
1336 0 : pgoff = 0;
1337 0 : vm_flags |= VM_SHARED | VM_MAYSHARE;
1338 0 : break;
1339 : case MAP_PRIVATE:
1340 : /*
1341 : * Set pgoff according to addr for anon_vma.
1342 : */
1343 0 : pgoff = addr >> PAGE_SHIFT;
1344 0 : break;
1345 : default:
1346 : return -EINVAL;
1347 : }
1348 : }
1349 :
1350 : /*
1351 : * Set 'VM_NORESERVE' if we should not account for the
1352 : * memory use of this mapping.
1353 : */
1354 0 : if (flags & MAP_NORESERVE) {
1355 : /* We honor MAP_NORESERVE if allowed to overcommit */
1356 0 : if (sysctl_overcommit_memory != OVERCOMMIT_NEVER)
1357 0 : vm_flags |= VM_NORESERVE;
1358 :
1359 : /* hugetlb applies strict overcommit unless MAP_NORESERVE */
1360 : if (file && is_file_hugepages(file))
1361 : vm_flags |= VM_NORESERVE;
1362 : }
1363 :
1364 0 : addr = mmap_region(file, addr, len, vm_flags, pgoff, uf);
1365 0 : if (!IS_ERR_VALUE(addr) &&
1366 0 : ((vm_flags & VM_LOCKED) ||
1367 0 : (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE))
1368 0 : *populate = len;
1369 : return addr;
1370 : }
1371 :
1372 0 : unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
1373 : unsigned long prot, unsigned long flags,
1374 : unsigned long fd, unsigned long pgoff)
1375 : {
1376 0 : struct file *file = NULL;
1377 : unsigned long retval;
1378 :
1379 0 : if (!(flags & MAP_ANONYMOUS)) {
1380 0 : audit_mmap_fd(fd, flags);
1381 0 : file = fget(fd);
1382 0 : if (!file)
1383 : return -EBADF;
1384 : if (is_file_hugepages(file)) {
1385 : len = ALIGN(len, huge_page_size(hstate_file(file)));
1386 0 : } else if (unlikely(flags & MAP_HUGETLB)) {
1387 : retval = -EINVAL;
1388 : goto out_fput;
1389 : }
1390 0 : } else if (flags & MAP_HUGETLB) {
1391 : struct hstate *hs;
1392 :
1393 : hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
1394 : if (!hs)
1395 : return -EINVAL;
1396 :
1397 : len = ALIGN(len, huge_page_size(hs));
1398 : /*
1399 : * VM_NORESERVE is used because the reservations will be
1400 : * taken when vm_ops->mmap() is called
1401 : */
1402 : file = hugetlb_file_setup(HUGETLB_ANON_FILE, len,
1403 : VM_NORESERVE,
1404 : HUGETLB_ANONHUGE_INODE,
1405 : (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
1406 : if (IS_ERR(file))
1407 : return PTR_ERR(file);
1408 : }
1409 :
1410 0 : retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
1411 : out_fput:
1412 0 : if (file)
1413 0 : fput(file);
1414 : return retval;
1415 : }
1416 :
1417 0 : SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1418 : unsigned long, prot, unsigned long, flags,
1419 : unsigned long, fd, unsigned long, pgoff)
1420 : {
1421 0 : return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
1422 : }
1423 :
1424 : #ifdef __ARCH_WANT_SYS_OLD_MMAP
1425 : struct mmap_arg_struct {
1426 : unsigned long addr;
1427 : unsigned long len;
1428 : unsigned long prot;
1429 : unsigned long flags;
1430 : unsigned long fd;
1431 : unsigned long offset;
1432 : };
1433 :
1434 : SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1435 : {
1436 : struct mmap_arg_struct a;
1437 :
1438 : if (copy_from_user(&a, arg, sizeof(a)))
1439 : return -EFAULT;
1440 : if (offset_in_page(a.offset))
1441 : return -EINVAL;
1442 :
1443 : return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1444 : a.offset >> PAGE_SHIFT);
1445 : }
1446 : #endif /* __ARCH_WANT_SYS_OLD_MMAP */
1447 :
1448 : /*
1449 : * Some shared mappings will want the pages marked read-only
1450 : * to track write events. If so, we'll downgrade vm_page_prot
1451 : * to the private version (using protection_map[] without the
1452 : * VM_SHARED bit).
1453 : */
1454 0 : int vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot)
1455 : {
1456 0 : vm_flags_t vm_flags = vma->vm_flags;
1457 0 : const struct vm_operations_struct *vm_ops = vma->vm_ops;
1458 :
1459 : /* If it was private or non-writable, the write bit is already clear */
1460 0 : if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
1461 : return 0;
1462 :
1463 : /* The backer wishes to know when pages are first written to? */
1464 0 : if (vm_ops && (vm_ops->page_mkwrite || vm_ops->pfn_mkwrite))
1465 : return 1;
1466 :
1467 : /* The open routine did something to the protections that pgprot_modify
1468 : * won't preserve? */
1469 0 : if (pgprot_val(vm_page_prot) !=
1470 0 : pgprot_val(vm_pgprot_modify(vm_page_prot, vm_flags)))
1471 : return 0;
1472 :
1473 : /*
1474 : * Do we need to track softdirty? hugetlb does not support softdirty
1475 : * tracking yet.
1476 : */
1477 0 : if (vma_soft_dirty_enabled(vma) && !is_vm_hugetlb_page(vma))
1478 : return 1;
1479 :
1480 : /* Do we need write faults for uffd-wp tracking? */
1481 0 : if (userfaultfd_wp(vma))
1482 : return 1;
1483 :
1484 : /* Specialty mapping? */
1485 0 : if (vm_flags & VM_PFNMAP)
1486 : return 0;
1487 :
1488 : /* Can the mapping track the dirty pages? */
1489 0 : return vma->vm_file && vma->vm_file->f_mapping &&
1490 0 : mapping_can_writeback(vma->vm_file->f_mapping);
1491 : }
1492 :
1493 : /*
1494 : * We account for memory if it's a private writeable mapping,
1495 : * not hugepages and VM_NORESERVE wasn't set.
1496 : */
1497 : static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags)
1498 : {
1499 : /*
1500 : * hugetlb has its own accounting separate from the core VM
1501 : * VM_HUGETLB may not be set yet so we cannot check for that flag.
1502 : */
1503 : if (file && is_file_hugepages(file))
1504 : return 0;
1505 :
1506 0 : return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE;
1507 : }
1508 :
1509 : /**
1510 : * unmapped_area() - Find an area between the low_limit and the high_limit with
1511 : * the correct alignment and offset, all from @info. Note: current->mm is used
1512 : * for the search.
1513 : *
1514 : * @info: The unmapped area information including the range [low_limit -
1515 : * high_limit), the alignment offset and mask.
1516 : *
1517 : * Return: A memory address or -ENOMEM.
1518 : */
1519 0 : static unsigned long unmapped_area(struct vm_unmapped_area_info *info)
1520 : {
1521 : unsigned long length, gap;
1522 :
1523 0 : MA_STATE(mas, ¤t->mm->mm_mt, 0, 0);
1524 :
1525 : /* Adjust search length to account for worst case alignment overhead */
1526 0 : length = info->length + info->align_mask;
1527 0 : if (length < info->length)
1528 : return -ENOMEM;
1529 :
1530 0 : if (mas_empty_area(&mas, info->low_limit, info->high_limit - 1,
1531 : length))
1532 : return -ENOMEM;
1533 :
1534 0 : gap = mas.index;
1535 0 : gap += (info->align_offset - gap) & info->align_mask;
1536 0 : return gap;
1537 : }
1538 :
1539 : /**
1540 : * unmapped_area_topdown() - Find an area between the low_limit and the
1541 : * high_limit with the correct alignment and offset at the highest available
1542 : * address, all from @info. Note: current->mm is used for the search.
1543 : *
1544 : * @info: The unmapped area information including the range [low_limit -
1545 : * high_limit), the alignment offset and mask.
1546 : *
1547 : * Return: A memory address or -ENOMEM.
1548 : */
1549 0 : static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
1550 : {
1551 : unsigned long length, gap;
1552 :
1553 0 : MA_STATE(mas, ¤t->mm->mm_mt, 0, 0);
1554 : /* Adjust search length to account for worst case alignment overhead */
1555 0 : length = info->length + info->align_mask;
1556 0 : if (length < info->length)
1557 : return -ENOMEM;
1558 :
1559 0 : if (mas_empty_area_rev(&mas, info->low_limit, info->high_limit - 1,
1560 : length))
1561 : return -ENOMEM;
1562 :
1563 0 : gap = mas.last + 1 - info->length;
1564 0 : gap -= (gap - info->align_offset) & info->align_mask;
1565 0 : return gap;
1566 : }
1567 :
1568 : /*
1569 : * Search for an unmapped address range.
1570 : *
1571 : * We are looking for a range that:
1572 : * - does not intersect with any VMA;
1573 : * - is contained within the [low_limit, high_limit) interval;
1574 : * - is at least the desired size.
1575 : * - satisfies (begin_addr & align_mask) == (align_offset & align_mask)
1576 : */
1577 0 : unsigned long vm_unmapped_area(struct vm_unmapped_area_info *info)
1578 : {
1579 : unsigned long addr;
1580 :
1581 0 : if (info->flags & VM_UNMAPPED_AREA_TOPDOWN)
1582 0 : addr = unmapped_area_topdown(info);
1583 : else
1584 0 : addr = unmapped_area(info);
1585 :
1586 0 : trace_vm_unmapped_area(addr, info);
1587 0 : return addr;
1588 : }
1589 :
1590 : /* Get an address range which is currently unmapped.
1591 : * For shmat() with addr=0.
1592 : *
1593 : * Ugly calling convention alert:
1594 : * Return value with the low bits set means error value,
1595 : * ie
1596 : * if (ret & ~PAGE_MASK)
1597 : * error = ret;
1598 : *
1599 : * This function "knows" that -ENOMEM has the bits set.
1600 : */
1601 : unsigned long
1602 0 : generic_get_unmapped_area(struct file *filp, unsigned long addr,
1603 : unsigned long len, unsigned long pgoff,
1604 : unsigned long flags)
1605 : {
1606 0 : struct mm_struct *mm = current->mm;
1607 : struct vm_area_struct *vma, *prev;
1608 : struct vm_unmapped_area_info info;
1609 0 : const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags);
1610 :
1611 0 : if (len > mmap_end - mmap_min_addr)
1612 : return -ENOMEM;
1613 :
1614 0 : if (flags & MAP_FIXED)
1615 : return addr;
1616 :
1617 0 : if (addr) {
1618 0 : addr = PAGE_ALIGN(addr);
1619 0 : vma = find_vma_prev(mm, addr, &prev);
1620 0 : if (mmap_end - len >= addr && addr >= mmap_min_addr &&
1621 0 : (!vma || addr + len <= vm_start_gap(vma)) &&
1622 0 : (!prev || addr >= vm_end_gap(prev)))
1623 : return addr;
1624 : }
1625 :
1626 0 : info.flags = 0;
1627 0 : info.length = len;
1628 0 : info.low_limit = mm->mmap_base;
1629 0 : info.high_limit = mmap_end;
1630 0 : info.align_mask = 0;
1631 0 : info.align_offset = 0;
1632 0 : return vm_unmapped_area(&info);
1633 : }
1634 :
1635 : #ifndef HAVE_ARCH_UNMAPPED_AREA
1636 : unsigned long
1637 0 : arch_get_unmapped_area(struct file *filp, unsigned long addr,
1638 : unsigned long len, unsigned long pgoff,
1639 : unsigned long flags)
1640 : {
1641 0 : return generic_get_unmapped_area(filp, addr, len, pgoff, flags);
1642 : }
1643 : #endif
1644 :
1645 : /*
1646 : * This mmap-allocator allocates new areas top-down from below the
1647 : * stack's low limit (the base):
1648 : */
1649 : unsigned long
1650 0 : generic_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
1651 : unsigned long len, unsigned long pgoff,
1652 : unsigned long flags)
1653 : {
1654 : struct vm_area_struct *vma, *prev;
1655 0 : struct mm_struct *mm = current->mm;
1656 : struct vm_unmapped_area_info info;
1657 0 : const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags);
1658 :
1659 : /* requested length too big for entire address space */
1660 0 : if (len > mmap_end - mmap_min_addr)
1661 : return -ENOMEM;
1662 :
1663 0 : if (flags & MAP_FIXED)
1664 : return addr;
1665 :
1666 : /* requesting a specific address */
1667 0 : if (addr) {
1668 0 : addr = PAGE_ALIGN(addr);
1669 0 : vma = find_vma_prev(mm, addr, &prev);
1670 0 : if (mmap_end - len >= addr && addr >= mmap_min_addr &&
1671 0 : (!vma || addr + len <= vm_start_gap(vma)) &&
1672 0 : (!prev || addr >= vm_end_gap(prev)))
1673 : return addr;
1674 : }
1675 :
1676 0 : info.flags = VM_UNMAPPED_AREA_TOPDOWN;
1677 0 : info.length = len;
1678 0 : info.low_limit = max(PAGE_SIZE, mmap_min_addr);
1679 0 : info.high_limit = arch_get_mmap_base(addr, mm->mmap_base);
1680 0 : info.align_mask = 0;
1681 0 : info.align_offset = 0;
1682 0 : addr = vm_unmapped_area(&info);
1683 :
1684 : /*
1685 : * A failed mmap() very likely causes application failure,
1686 : * so fall back to the bottom-up function here. This scenario
1687 : * can happen with large stack limits and large mmap()
1688 : * allocations.
1689 : */
1690 0 : if (offset_in_page(addr)) {
1691 : VM_BUG_ON(addr != -ENOMEM);
1692 0 : info.flags = 0;
1693 0 : info.low_limit = TASK_UNMAPPED_BASE;
1694 0 : info.high_limit = mmap_end;
1695 0 : addr = vm_unmapped_area(&info);
1696 : }
1697 :
1698 : return addr;
1699 : }
1700 :
1701 : #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1702 : unsigned long
1703 0 : arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
1704 : unsigned long len, unsigned long pgoff,
1705 : unsigned long flags)
1706 : {
1707 0 : return generic_get_unmapped_area_topdown(filp, addr, len, pgoff, flags);
1708 : }
1709 : #endif
1710 :
1711 : unsigned long
1712 0 : get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1713 : unsigned long pgoff, unsigned long flags)
1714 : {
1715 : unsigned long (*get_area)(struct file *, unsigned long,
1716 : unsigned long, unsigned long, unsigned long);
1717 :
1718 0 : unsigned long error = arch_mmap_check(addr, len, flags);
1719 : if (error)
1720 : return error;
1721 :
1722 : /* Careful about overflows.. */
1723 0 : if (len > TASK_SIZE)
1724 : return -ENOMEM;
1725 :
1726 0 : get_area = current->mm->get_unmapped_area;
1727 0 : if (file) {
1728 0 : if (file->f_op->get_unmapped_area)
1729 0 : get_area = file->f_op->get_unmapped_area;
1730 0 : } else if (flags & MAP_SHARED) {
1731 : /*
1732 : * mmap_region() will call shmem_zero_setup() to create a file,
1733 : * so use shmem's get_unmapped_area in case it can be huge.
1734 : * do_mmap() will clear pgoff, so match alignment.
1735 : */
1736 0 : pgoff = 0;
1737 0 : get_area = shmem_get_unmapped_area;
1738 : }
1739 :
1740 0 : addr = get_area(file, addr, len, pgoff, flags);
1741 0 : if (IS_ERR_VALUE(addr))
1742 : return addr;
1743 :
1744 0 : if (addr > TASK_SIZE - len)
1745 : return -ENOMEM;
1746 0 : if (offset_in_page(addr))
1747 : return -EINVAL;
1748 :
1749 0 : error = security_mmap_addr(addr);
1750 0 : return error ? error : addr;
1751 : }
1752 :
1753 : EXPORT_SYMBOL(get_unmapped_area);
1754 :
1755 : /**
1756 : * find_vma_intersection() - Look up the first VMA which intersects the interval
1757 : * @mm: The process address space.
1758 : * @start_addr: The inclusive start user address.
1759 : * @end_addr: The exclusive end user address.
1760 : *
1761 : * Returns: The first VMA within the provided range, %NULL otherwise. Assumes
1762 : * start_addr < end_addr.
1763 : */
1764 0 : struct vm_area_struct *find_vma_intersection(struct mm_struct *mm,
1765 : unsigned long start_addr,
1766 : unsigned long end_addr)
1767 : {
1768 0 : unsigned long index = start_addr;
1769 :
1770 0 : mmap_assert_locked(mm);
1771 0 : return mt_find(&mm->mm_mt, &index, end_addr - 1);
1772 : }
1773 : EXPORT_SYMBOL(find_vma_intersection);
1774 :
1775 : /**
1776 : * find_vma() - Find the VMA for a given address, or the next VMA.
1777 : * @mm: The mm_struct to check
1778 : * @addr: The address
1779 : *
1780 : * Returns: The VMA associated with addr, or the next VMA.
1781 : * May return %NULL in the case of no VMA at addr or above.
1782 : */
1783 0 : struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
1784 : {
1785 0 : unsigned long index = addr;
1786 :
1787 0 : mmap_assert_locked(mm);
1788 0 : return mt_find(&mm->mm_mt, &index, ULONG_MAX);
1789 : }
1790 : EXPORT_SYMBOL(find_vma);
1791 :
1792 : /**
1793 : * find_vma_prev() - Find the VMA for a given address, or the next vma and
1794 : * set %pprev to the previous VMA, if any.
1795 : * @mm: The mm_struct to check
1796 : * @addr: The address
1797 : * @pprev: The pointer to set to the previous VMA
1798 : *
1799 : * Note that RCU lock is missing here since the external mmap_lock() is used
1800 : * instead.
1801 : *
1802 : * Returns: The VMA associated with @addr, or the next vma.
1803 : * May return %NULL in the case of no vma at addr or above.
1804 : */
1805 : struct vm_area_struct *
1806 0 : find_vma_prev(struct mm_struct *mm, unsigned long addr,
1807 : struct vm_area_struct **pprev)
1808 : {
1809 : struct vm_area_struct *vma;
1810 0 : MA_STATE(mas, &mm->mm_mt, addr, addr);
1811 :
1812 0 : vma = mas_walk(&mas);
1813 0 : *pprev = mas_prev(&mas, 0);
1814 0 : if (!vma)
1815 0 : vma = mas_next(&mas, ULONG_MAX);
1816 0 : return vma;
1817 : }
1818 :
1819 : /*
1820 : * Verify that the stack growth is acceptable and
1821 : * update accounting. This is shared with both the
1822 : * grow-up and grow-down cases.
1823 : */
1824 0 : static int acct_stack_growth(struct vm_area_struct *vma,
1825 : unsigned long size, unsigned long grow)
1826 : {
1827 0 : struct mm_struct *mm = vma->vm_mm;
1828 : unsigned long new_start;
1829 :
1830 : /* address space limit tests */
1831 0 : if (!may_expand_vm(mm, vma->vm_flags, grow))
1832 : return -ENOMEM;
1833 :
1834 : /* Stack limit test */
1835 0 : if (size > rlimit(RLIMIT_STACK))
1836 : return -ENOMEM;
1837 :
1838 : /* mlock limit tests */
1839 0 : if (mlock_future_check(mm, vma->vm_flags, grow << PAGE_SHIFT))
1840 : return -ENOMEM;
1841 :
1842 : /* Check to ensure the stack will not grow into a hugetlb-only region */
1843 0 : new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
1844 0 : vma->vm_end - size;
1845 0 : if (is_hugepage_only_range(vma->vm_mm, new_start, size))
1846 : return -EFAULT;
1847 :
1848 : /*
1849 : * Overcommit.. This must be the final test, as it will
1850 : * update security statistics.
1851 : */
1852 0 : if (security_vm_enough_memory_mm(mm, grow))
1853 : return -ENOMEM;
1854 :
1855 : return 0;
1856 : }
1857 :
1858 : #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
1859 : /*
1860 : * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
1861 : * vma is the last one with address > vma->vm_end. Have to extend vma.
1862 : */
1863 : int expand_upwards(struct vm_area_struct *vma, unsigned long address)
1864 : {
1865 : struct mm_struct *mm = vma->vm_mm;
1866 : struct vm_area_struct *next;
1867 : unsigned long gap_addr;
1868 : int error = 0;
1869 : MA_STATE(mas, &mm->mm_mt, 0, 0);
1870 :
1871 : if (!(vma->vm_flags & VM_GROWSUP))
1872 : return -EFAULT;
1873 :
1874 : /* Guard against exceeding limits of the address space. */
1875 : address &= PAGE_MASK;
1876 : if (address >= (TASK_SIZE & PAGE_MASK))
1877 : return -ENOMEM;
1878 : address += PAGE_SIZE;
1879 :
1880 : /* Enforce stack_guard_gap */
1881 : gap_addr = address + stack_guard_gap;
1882 :
1883 : /* Guard against overflow */
1884 : if (gap_addr < address || gap_addr > TASK_SIZE)
1885 : gap_addr = TASK_SIZE;
1886 :
1887 : next = find_vma_intersection(mm, vma->vm_end, gap_addr);
1888 : if (next && vma_is_accessible(next)) {
1889 : if (!(next->vm_flags & VM_GROWSUP))
1890 : return -ENOMEM;
1891 : /* Check that both stack segments have the same anon_vma? */
1892 : }
1893 :
1894 : if (mas_preallocate(&mas, GFP_KERNEL))
1895 : return -ENOMEM;
1896 :
1897 : /* We must make sure the anon_vma is allocated. */
1898 : if (unlikely(anon_vma_prepare(vma))) {
1899 : mas_destroy(&mas);
1900 : return -ENOMEM;
1901 : }
1902 :
1903 : /*
1904 : * vma->vm_start/vm_end cannot change under us because the caller
1905 : * is required to hold the mmap_lock in read mode. We need the
1906 : * anon_vma lock to serialize against concurrent expand_stacks.
1907 : */
1908 : anon_vma_lock_write(vma->anon_vma);
1909 :
1910 : /* Somebody else might have raced and expanded it already */
1911 : if (address > vma->vm_end) {
1912 : unsigned long size, grow;
1913 :
1914 : size = address - vma->vm_start;
1915 : grow = (address - vma->vm_end) >> PAGE_SHIFT;
1916 :
1917 : error = -ENOMEM;
1918 : if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
1919 : error = acct_stack_growth(vma, size, grow);
1920 : if (!error) {
1921 : /*
1922 : * We only hold a shared mmap_lock lock here, so
1923 : * we need to protect against concurrent vma
1924 : * expansions. anon_vma_lock_write() doesn't
1925 : * help here, as we don't guarantee that all
1926 : * growable vmas in a mm share the same root
1927 : * anon vma. So, we reuse mm->page_table_lock
1928 : * to guard against concurrent vma expansions.
1929 : */
1930 : spin_lock(&mm->page_table_lock);
1931 : if (vma->vm_flags & VM_LOCKED)
1932 : mm->locked_vm += grow;
1933 : vm_stat_account(mm, vma->vm_flags, grow);
1934 : anon_vma_interval_tree_pre_update_vma(vma);
1935 : vma->vm_end = address;
1936 : /* Overwrite old entry in mtree. */
1937 : mas_set_range(&mas, vma->vm_start, address - 1);
1938 : mas_store_prealloc(&mas, vma);
1939 : anon_vma_interval_tree_post_update_vma(vma);
1940 : spin_unlock(&mm->page_table_lock);
1941 :
1942 : perf_event_mmap(vma);
1943 : }
1944 : }
1945 : }
1946 : anon_vma_unlock_write(vma->anon_vma);
1947 : khugepaged_enter_vma(vma, vma->vm_flags);
1948 : mas_destroy(&mas);
1949 : return error;
1950 : }
1951 : #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
1952 :
1953 : /*
1954 : * vma is the first one with address < vma->vm_start. Have to extend vma.
1955 : */
1956 0 : int expand_downwards(struct vm_area_struct *vma, unsigned long address)
1957 : {
1958 0 : struct mm_struct *mm = vma->vm_mm;
1959 0 : MA_STATE(mas, &mm->mm_mt, vma->vm_start, vma->vm_start);
1960 : struct vm_area_struct *prev;
1961 0 : int error = 0;
1962 :
1963 0 : address &= PAGE_MASK;
1964 0 : if (address < mmap_min_addr)
1965 : return -EPERM;
1966 :
1967 : /* Enforce stack_guard_gap */
1968 0 : prev = mas_prev(&mas, 0);
1969 : /* Check that both stack segments have the same anon_vma? */
1970 0 : if (prev && !(prev->vm_flags & VM_GROWSDOWN) &&
1971 0 : vma_is_accessible(prev)) {
1972 0 : if (address - prev->vm_end < stack_guard_gap)
1973 : return -ENOMEM;
1974 : }
1975 :
1976 0 : if (mas_preallocate(&mas, GFP_KERNEL))
1977 : return -ENOMEM;
1978 :
1979 : /* We must make sure the anon_vma is allocated. */
1980 0 : if (unlikely(anon_vma_prepare(vma))) {
1981 0 : mas_destroy(&mas);
1982 0 : return -ENOMEM;
1983 : }
1984 :
1985 : /*
1986 : * vma->vm_start/vm_end cannot change under us because the caller
1987 : * is required to hold the mmap_lock in read mode. We need the
1988 : * anon_vma lock to serialize against concurrent expand_stacks.
1989 : */
1990 0 : anon_vma_lock_write(vma->anon_vma);
1991 :
1992 : /* Somebody else might have raced and expanded it already */
1993 0 : if (address < vma->vm_start) {
1994 : unsigned long size, grow;
1995 :
1996 0 : size = vma->vm_end - address;
1997 0 : grow = (vma->vm_start - address) >> PAGE_SHIFT;
1998 :
1999 0 : error = -ENOMEM;
2000 0 : if (grow <= vma->vm_pgoff) {
2001 0 : error = acct_stack_growth(vma, size, grow);
2002 0 : if (!error) {
2003 : /*
2004 : * We only hold a shared mmap_lock lock here, so
2005 : * we need to protect against concurrent vma
2006 : * expansions. anon_vma_lock_write() doesn't
2007 : * help here, as we don't guarantee that all
2008 : * growable vmas in a mm share the same root
2009 : * anon vma. So, we reuse mm->page_table_lock
2010 : * to guard against concurrent vma expansions.
2011 : */
2012 0 : spin_lock(&mm->page_table_lock);
2013 0 : if (vma->vm_flags & VM_LOCKED)
2014 0 : mm->locked_vm += grow;
2015 0 : vm_stat_account(mm, vma->vm_flags, grow);
2016 0 : anon_vma_interval_tree_pre_update_vma(vma);
2017 0 : vma->vm_start = address;
2018 0 : vma->vm_pgoff -= grow;
2019 : /* Overwrite old entry in mtree. */
2020 0 : mas_set_range(&mas, address, vma->vm_end - 1);
2021 0 : mas_store_prealloc(&mas, vma);
2022 0 : anon_vma_interval_tree_post_update_vma(vma);
2023 0 : spin_unlock(&mm->page_table_lock);
2024 :
2025 : perf_event_mmap(vma);
2026 : }
2027 : }
2028 : }
2029 0 : anon_vma_unlock_write(vma->anon_vma);
2030 0 : khugepaged_enter_vma(vma, vma->vm_flags);
2031 0 : mas_destroy(&mas);
2032 0 : return error;
2033 : }
2034 :
2035 : /* enforced gap between the expanding stack and other mappings. */
2036 : unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT;
2037 :
2038 0 : static int __init cmdline_parse_stack_guard_gap(char *p)
2039 : {
2040 : unsigned long val;
2041 : char *endptr;
2042 :
2043 0 : val = simple_strtoul(p, &endptr, 10);
2044 0 : if (!*endptr)
2045 0 : stack_guard_gap = val << PAGE_SHIFT;
2046 :
2047 0 : return 1;
2048 : }
2049 : __setup("stack_guard_gap=", cmdline_parse_stack_guard_gap);
2050 :
2051 : #ifdef CONFIG_STACK_GROWSUP
2052 : int expand_stack(struct vm_area_struct *vma, unsigned long address)
2053 : {
2054 : return expand_upwards(vma, address);
2055 : }
2056 :
2057 : struct vm_area_struct *
2058 : find_extend_vma(struct mm_struct *mm, unsigned long addr)
2059 : {
2060 : struct vm_area_struct *vma, *prev;
2061 :
2062 : addr &= PAGE_MASK;
2063 : vma = find_vma_prev(mm, addr, &prev);
2064 : if (vma && (vma->vm_start <= addr))
2065 : return vma;
2066 : if (!prev || expand_stack(prev, addr))
2067 : return NULL;
2068 : if (prev->vm_flags & VM_LOCKED)
2069 : populate_vma_page_range(prev, addr, prev->vm_end, NULL);
2070 : return prev;
2071 : }
2072 : #else
2073 0 : int expand_stack(struct vm_area_struct *vma, unsigned long address)
2074 : {
2075 0 : return expand_downwards(vma, address);
2076 : }
2077 :
2078 : struct vm_area_struct *
2079 0 : find_extend_vma(struct mm_struct *mm, unsigned long addr)
2080 : {
2081 : struct vm_area_struct *vma;
2082 : unsigned long start;
2083 :
2084 0 : addr &= PAGE_MASK;
2085 0 : vma = find_vma(mm, addr);
2086 0 : if (!vma)
2087 : return NULL;
2088 0 : if (vma->vm_start <= addr)
2089 : return vma;
2090 0 : if (!(vma->vm_flags & VM_GROWSDOWN))
2091 : return NULL;
2092 0 : start = vma->vm_start;
2093 0 : if (expand_stack(vma, addr))
2094 : return NULL;
2095 0 : if (vma->vm_flags & VM_LOCKED)
2096 0 : populate_vma_page_range(vma, addr, start, NULL);
2097 : return vma;
2098 : }
2099 : #endif
2100 :
2101 : EXPORT_SYMBOL_GPL(find_extend_vma);
2102 :
2103 : /*
2104 : * Ok - we have the memory areas we should free on a maple tree so release them,
2105 : * and do the vma updates.
2106 : *
2107 : * Called with the mm semaphore held.
2108 : */
2109 0 : static inline void remove_mt(struct mm_struct *mm, struct ma_state *mas)
2110 : {
2111 0 : unsigned long nr_accounted = 0;
2112 : struct vm_area_struct *vma;
2113 :
2114 : /* Update high watermark before we lower total_vm */
2115 : update_hiwater_vm(mm);
2116 0 : mas_for_each(mas, vma, ULONG_MAX) {
2117 0 : long nrpages = vma_pages(vma);
2118 :
2119 0 : if (vma->vm_flags & VM_ACCOUNT)
2120 0 : nr_accounted += nrpages;
2121 0 : vm_stat_account(mm, vma->vm_flags, -nrpages);
2122 0 : remove_vma(vma);
2123 : }
2124 0 : vm_unacct_memory(nr_accounted);
2125 : validate_mm(mm);
2126 0 : }
2127 :
2128 : /*
2129 : * Get rid of page table information in the indicated region.
2130 : *
2131 : * Called with the mm semaphore held.
2132 : */
2133 0 : static void unmap_region(struct mm_struct *mm, struct maple_tree *mt,
2134 : struct vm_area_struct *vma, struct vm_area_struct *prev,
2135 : struct vm_area_struct *next,
2136 : unsigned long start, unsigned long end, bool mm_wr_locked)
2137 : {
2138 : struct mmu_gather tlb;
2139 :
2140 0 : lru_add_drain();
2141 0 : tlb_gather_mmu(&tlb, mm);
2142 0 : update_hiwater_rss(mm);
2143 0 : unmap_vmas(&tlb, mt, vma, start, end, mm_wr_locked);
2144 0 : free_pgtables(&tlb, mt, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS,
2145 : next ? next->vm_start : USER_PGTABLES_CEILING);
2146 0 : tlb_finish_mmu(&tlb);
2147 0 : }
2148 :
2149 : /*
2150 : * __split_vma() bypasses sysctl_max_map_count checking. We use this where it
2151 : * has already been checked or doesn't make sense to fail.
2152 : * VMA Iterator will point to the end VMA.
2153 : */
2154 0 : int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
2155 : unsigned long addr, int new_below)
2156 : {
2157 : struct vma_prepare vp;
2158 : struct vm_area_struct *new;
2159 : int err;
2160 :
2161 : validate_mm_mt(vma->vm_mm);
2162 :
2163 0 : WARN_ON(vma->vm_start >= addr);
2164 0 : WARN_ON(vma->vm_end <= addr);
2165 :
2166 0 : if (vma->vm_ops && vma->vm_ops->may_split) {
2167 0 : err = vma->vm_ops->may_split(vma, addr);
2168 0 : if (err)
2169 : return err;
2170 : }
2171 :
2172 0 : new = vm_area_dup(vma);
2173 0 : if (!new)
2174 : return -ENOMEM;
2175 :
2176 0 : err = -ENOMEM;
2177 0 : if (vma_iter_prealloc(vmi))
2178 : goto out_free_vma;
2179 :
2180 0 : if (new_below) {
2181 0 : new->vm_end = addr;
2182 : } else {
2183 0 : new->vm_start = addr;
2184 0 : new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
2185 : }
2186 :
2187 0 : err = vma_dup_policy(vma, new);
2188 : if (err)
2189 : goto out_free_vmi;
2190 :
2191 0 : err = anon_vma_clone(new, vma);
2192 0 : if (err)
2193 : goto out_free_mpol;
2194 :
2195 0 : if (new->vm_file)
2196 0 : get_file(new->vm_file);
2197 :
2198 0 : if (new->vm_ops && new->vm_ops->open)
2199 0 : new->vm_ops->open(new);
2200 :
2201 0 : vma_adjust_trans_huge(vma, vma->vm_start, addr, 0);
2202 0 : init_vma_prep(&vp, vma);
2203 0 : vp.insert = new;
2204 0 : vma_prepare(&vp);
2205 :
2206 0 : if (new_below) {
2207 0 : vma->vm_start = addr;
2208 0 : vma->vm_pgoff += (addr - new->vm_start) >> PAGE_SHIFT;
2209 : } else {
2210 0 : vma->vm_end = addr;
2211 : }
2212 :
2213 : /* vma_complete stores the new vma */
2214 0 : vma_complete(&vp, vmi, vma->vm_mm);
2215 :
2216 : /* Success. */
2217 0 : if (new_below)
2218 : vma_next(vmi);
2219 : validate_mm_mt(vma->vm_mm);
2220 : return 0;
2221 :
2222 : out_free_mpol:
2223 : mpol_put(vma_policy(new));
2224 : out_free_vmi:
2225 : vma_iter_free(vmi);
2226 : out_free_vma:
2227 0 : vm_area_free(new);
2228 : validate_mm_mt(vma->vm_mm);
2229 0 : return err;
2230 : }
2231 :
2232 : /*
2233 : * Split a vma into two pieces at address 'addr', a new vma is allocated
2234 : * either for the first part or the tail.
2235 : */
2236 0 : int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
2237 : unsigned long addr, int new_below)
2238 : {
2239 0 : if (vma->vm_mm->map_count >= sysctl_max_map_count)
2240 : return -ENOMEM;
2241 :
2242 0 : return __split_vma(vmi, vma, addr, new_below);
2243 : }
2244 :
2245 0 : static inline int munmap_sidetree(struct vm_area_struct *vma,
2246 : struct ma_state *mas_detach)
2247 : {
2248 0 : mas_set_range(mas_detach, vma->vm_start, vma->vm_end - 1);
2249 0 : if (mas_store_gfp(mas_detach, vma, GFP_KERNEL))
2250 : return -ENOMEM;
2251 :
2252 0 : if (vma->vm_flags & VM_LOCKED)
2253 0 : vma->vm_mm->locked_vm -= vma_pages(vma);
2254 :
2255 : return 0;
2256 : }
2257 :
2258 : /*
2259 : * do_vmi_align_munmap() - munmap the aligned region from @start to @end.
2260 : * @vmi: The vma iterator
2261 : * @vma: The starting vm_area_struct
2262 : * @mm: The mm_struct
2263 : * @start: The aligned start address to munmap.
2264 : * @end: The aligned end address to munmap.
2265 : * @uf: The userfaultfd list_head
2266 : * @downgrade: Set to true to attempt a write downgrade of the mmap_lock
2267 : *
2268 : * If @downgrade is true, check return code for potential release of the lock.
2269 : */
2270 : static int
2271 0 : do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
2272 : struct mm_struct *mm, unsigned long start,
2273 : unsigned long end, struct list_head *uf, bool downgrade)
2274 : {
2275 0 : struct vm_area_struct *prev, *next = NULL;
2276 : struct maple_tree mt_detach;
2277 0 : int count = 0;
2278 0 : int error = -ENOMEM;
2279 0 : MA_STATE(mas_detach, &mt_detach, 0, 0);
2280 0 : mt_init_flags(&mt_detach, MT_FLAGS_LOCK_EXTERN);
2281 : mt_set_external_lock(&mt_detach, &mm->mmap_lock);
2282 :
2283 : /*
2284 : * If we need to split any vma, do it now to save pain later.
2285 : *
2286 : * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
2287 : * unmapped vm_area_struct will remain in use: so lower split_vma
2288 : * places tmp vma above, and higher split_vma places tmp vma below.
2289 : */
2290 :
2291 : /* Does it split the first one? */
2292 0 : if (start > vma->vm_start) {
2293 :
2294 : /*
2295 : * Make sure that map_count on return from munmap() will
2296 : * not exceed its limit; but let map_count go just above
2297 : * its limit temporarily, to help free resources as expected.
2298 : */
2299 0 : if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count)
2300 : goto map_count_exceeded;
2301 :
2302 0 : error = __split_vma(vmi, vma, start, 0);
2303 0 : if (error)
2304 : goto start_split_failed;
2305 :
2306 0 : vma = vma_iter_load(vmi);
2307 : }
2308 :
2309 0 : prev = vma_prev(vmi);
2310 0 : if (unlikely((!prev)))
2311 : vma_iter_set(vmi, start);
2312 :
2313 : /*
2314 : * Detach a range of VMAs from the mm. Using next as a temp variable as
2315 : * it is always overwritten.
2316 : */
2317 0 : for_each_vma_range(*vmi, next, end) {
2318 : /* Does it split the end? */
2319 0 : if (next->vm_end > end) {
2320 0 : error = __split_vma(vmi, next, end, 0);
2321 0 : if (error)
2322 : goto end_split_failed;
2323 : }
2324 0 : error = munmap_sidetree(next, &mas_detach);
2325 0 : if (error)
2326 : goto munmap_sidetree_failed;
2327 :
2328 0 : count++;
2329 : #ifdef CONFIG_DEBUG_VM_MAPLE_TREE
2330 : BUG_ON(next->vm_start < start);
2331 : BUG_ON(next->vm_start > end);
2332 : #endif
2333 : }
2334 :
2335 0 : next = vma_next(vmi);
2336 : if (unlikely(uf)) {
2337 : /*
2338 : * If userfaultfd_unmap_prep returns an error the vmas
2339 : * will remain split, but userland will get a
2340 : * highly unexpected error anyway. This is no
2341 : * different than the case where the first of the two
2342 : * __split_vma fails, but we don't undo the first
2343 : * split, despite we could. This is unlikely enough
2344 : * failure that it's not worth optimizing it for.
2345 : */
2346 : error = userfaultfd_unmap_prep(mm, start, end, uf);
2347 :
2348 : if (error)
2349 : goto userfaultfd_error;
2350 : }
2351 :
2352 : #if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
2353 : /* Make sure no VMAs are about to be lost. */
2354 : {
2355 : MA_STATE(test, &mt_detach, start, end - 1);
2356 : struct vm_area_struct *vma_mas, *vma_test;
2357 : int test_count = 0;
2358 :
2359 : vma_iter_set(vmi, start);
2360 : rcu_read_lock();
2361 : vma_test = mas_find(&test, end - 1);
2362 : for_each_vma_range(*vmi, vma_mas, end) {
2363 : BUG_ON(vma_mas != vma_test);
2364 : test_count++;
2365 : vma_test = mas_next(&test, end - 1);
2366 : }
2367 : rcu_read_unlock();
2368 : BUG_ON(count != test_count);
2369 : }
2370 : #endif
2371 : /* Point of no return */
2372 0 : vma_iter_set(vmi, start);
2373 0 : if (vma_iter_clear_gfp(vmi, start, end, GFP_KERNEL))
2374 : return -ENOMEM;
2375 :
2376 0 : mm->map_count -= count;
2377 : /*
2378 : * Do not downgrade mmap_lock if we are next to VM_GROWSDOWN or
2379 : * VM_GROWSUP VMA. Such VMAs can change their size under
2380 : * down_read(mmap_lock) and collide with the VMA we are about to unmap.
2381 : */
2382 0 : if (downgrade) {
2383 0 : if (next && (next->vm_flags & VM_GROWSDOWN))
2384 : downgrade = false;
2385 : else if (prev && (prev->vm_flags & VM_GROWSUP))
2386 : downgrade = false;
2387 : else
2388 : mmap_write_downgrade(mm);
2389 : }
2390 :
2391 : /*
2392 : * We can free page tables without write-locking mmap_lock because VMAs
2393 : * were isolated before we downgraded mmap_lock.
2394 : */
2395 0 : unmap_region(mm, &mt_detach, vma, prev, next, start, end, !downgrade);
2396 : /* Statistics and freeing VMAs */
2397 0 : mas_set(&mas_detach, start);
2398 0 : remove_mt(mm, &mas_detach);
2399 0 : __mt_destroy(&mt_detach);
2400 :
2401 :
2402 : validate_mm(mm);
2403 0 : return downgrade ? 1 : 0;
2404 :
2405 : userfaultfd_error:
2406 : munmap_sidetree_failed:
2407 : end_split_failed:
2408 0 : __mt_destroy(&mt_detach);
2409 : start_split_failed:
2410 : map_count_exceeded:
2411 : return error;
2412 : }
2413 :
2414 : /*
2415 : * do_vmi_munmap() - munmap a given range.
2416 : * @vmi: The vma iterator
2417 : * @mm: The mm_struct
2418 : * @start: The start address to munmap
2419 : * @len: The length of the range to munmap
2420 : * @uf: The userfaultfd list_head
2421 : * @downgrade: set to true if the user wants to attempt to write_downgrade the
2422 : * mmap_lock
2423 : *
2424 : * This function takes a @mas that is either pointing to the previous VMA or set
2425 : * to MA_START and sets it up to remove the mapping(s). The @len will be
2426 : * aligned and any arch_unmap work will be preformed.
2427 : *
2428 : * Returns: -EINVAL on failure, 1 on success and unlock, 0 otherwise.
2429 : */
2430 0 : int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm,
2431 : unsigned long start, size_t len, struct list_head *uf,
2432 : bool downgrade)
2433 : {
2434 : unsigned long end;
2435 : struct vm_area_struct *vma;
2436 :
2437 0 : if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start)
2438 : return -EINVAL;
2439 :
2440 0 : end = start + PAGE_ALIGN(len);
2441 0 : if (end == start)
2442 : return -EINVAL;
2443 :
2444 : /* arch_unmap() might do unmaps itself. */
2445 0 : arch_unmap(mm, start, end);
2446 :
2447 : /* Find the first overlapping VMA */
2448 0 : vma = vma_find(vmi, end);
2449 0 : if (!vma)
2450 : return 0;
2451 :
2452 0 : return do_vmi_align_munmap(vmi, vma, mm, start, end, uf, downgrade);
2453 : }
2454 :
2455 : /* do_munmap() - Wrapper function for non-maple tree aware do_munmap() calls.
2456 : * @mm: The mm_struct
2457 : * @start: The start address to munmap
2458 : * @len: The length to be munmapped.
2459 : * @uf: The userfaultfd list_head
2460 : */
2461 0 : int do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
2462 : struct list_head *uf)
2463 : {
2464 0 : VMA_ITERATOR(vmi, mm, start);
2465 :
2466 0 : return do_vmi_munmap(&vmi, mm, start, len, uf, false);
2467 : }
2468 :
2469 0 : unsigned long mmap_region(struct file *file, unsigned long addr,
2470 : unsigned long len, vm_flags_t vm_flags, unsigned long pgoff,
2471 : struct list_head *uf)
2472 : {
2473 0 : struct mm_struct *mm = current->mm;
2474 0 : struct vm_area_struct *vma = NULL;
2475 : struct vm_area_struct *next, *prev, *merge;
2476 0 : pgoff_t pglen = len >> PAGE_SHIFT;
2477 0 : unsigned long charged = 0;
2478 0 : unsigned long end = addr + len;
2479 0 : unsigned long merge_start = addr, merge_end = end;
2480 : pgoff_t vm_pgoff;
2481 : int error;
2482 0 : VMA_ITERATOR(vmi, mm, addr);
2483 :
2484 : /* Check against address space limit. */
2485 0 : if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) {
2486 : unsigned long nr_pages;
2487 :
2488 : /*
2489 : * MAP_FIXED may remove pages of mappings that intersects with
2490 : * requested mapping. Account for the pages it would unmap.
2491 : */
2492 0 : nr_pages = count_vma_pages_range(mm, addr, end);
2493 :
2494 0 : if (!may_expand_vm(mm, vm_flags,
2495 : (len >> PAGE_SHIFT) - nr_pages))
2496 : return -ENOMEM;
2497 : }
2498 :
2499 : /* Unmap any existing mapping in the area */
2500 0 : if (do_vmi_munmap(&vmi, mm, addr, len, uf, false))
2501 : return -ENOMEM;
2502 :
2503 : /*
2504 : * Private writable mapping: check memory availability
2505 : */
2506 0 : if (accountable_mapping(file, vm_flags)) {
2507 0 : charged = len >> PAGE_SHIFT;
2508 0 : if (security_vm_enough_memory_mm(mm, charged))
2509 : return -ENOMEM;
2510 0 : vm_flags |= VM_ACCOUNT;
2511 : }
2512 :
2513 0 : next = vma_next(&vmi);
2514 0 : prev = vma_prev(&vmi);
2515 0 : if (vm_flags & VM_SPECIAL)
2516 : goto cannot_expand;
2517 :
2518 : /* Attempt to expand an old mapping */
2519 : /* Check next */
2520 0 : if (next && next->vm_start == end && !vma_policy(next) &&
2521 0 : can_vma_merge_before(next, vm_flags, NULL, file, pgoff+pglen,
2522 : NULL_VM_UFFD_CTX, NULL)) {
2523 0 : merge_end = next->vm_end;
2524 0 : vma = next;
2525 0 : vm_pgoff = next->vm_pgoff - pglen;
2526 : }
2527 :
2528 : /* Check prev */
2529 0 : if (prev && prev->vm_end == addr && !vma_policy(prev) &&
2530 0 : (vma ? can_vma_merge_after(prev, vm_flags, vma->anon_vma, file,
2531 : pgoff, vma->vm_userfaultfd_ctx, NULL) :
2532 0 : can_vma_merge_after(prev, vm_flags, NULL, file, pgoff,
2533 : NULL_VM_UFFD_CTX, NULL))) {
2534 0 : merge_start = prev->vm_start;
2535 0 : vma = prev;
2536 0 : vm_pgoff = prev->vm_pgoff;
2537 : }
2538 :
2539 :
2540 : /* Actually expand, if possible */
2541 0 : if (vma &&
2542 0 : !vma_expand(&vmi, vma, merge_start, merge_end, vm_pgoff, next)) {
2543 : khugepaged_enter_vma(vma, vm_flags);
2544 : goto expanded;
2545 : }
2546 :
2547 : cannot_expand:
2548 : /*
2549 : * Determine the object being mapped and call the appropriate
2550 : * specific mapper. the address has already been validated, but
2551 : * not unmapped, but the maps are removed from the list.
2552 : */
2553 0 : vma = vm_area_alloc(mm);
2554 0 : if (!vma) {
2555 : error = -ENOMEM;
2556 : goto unacct_error;
2557 : }
2558 :
2559 0 : vma_iter_set(&vmi, addr);
2560 0 : vma->vm_start = addr;
2561 0 : vma->vm_end = end;
2562 0 : vm_flags_init(vma, vm_flags);
2563 0 : vma->vm_page_prot = vm_get_page_prot(vm_flags);
2564 0 : vma->vm_pgoff = pgoff;
2565 :
2566 0 : if (file) {
2567 0 : if (vm_flags & VM_SHARED) {
2568 0 : error = mapping_map_writable(file->f_mapping);
2569 0 : if (error)
2570 : goto free_vma;
2571 : }
2572 :
2573 0 : vma->vm_file = get_file(file);
2574 0 : error = call_mmap(file, vma);
2575 0 : if (error)
2576 : goto unmap_and_free_vma;
2577 :
2578 : /*
2579 : * Expansion is handled above, merging is handled below.
2580 : * Drivers should not alter the address of the VMA.
2581 : */
2582 0 : error = -EINVAL;
2583 0 : if (WARN_ON((addr != vma->vm_start)))
2584 : goto close_and_free_vma;
2585 :
2586 0 : vma_iter_set(&vmi, addr);
2587 : /*
2588 : * If vm_flags changed after call_mmap(), we should try merge
2589 : * vma again as we may succeed this time.
2590 : */
2591 0 : if (unlikely(vm_flags != vma->vm_flags && prev)) {
2592 0 : merge = vma_merge(&vmi, mm, prev, vma->vm_start,
2593 : vma->vm_end, vma->vm_flags, NULL,
2594 : vma->vm_file, vma->vm_pgoff, NULL,
2595 : NULL_VM_UFFD_CTX, NULL);
2596 0 : if (merge) {
2597 : /*
2598 : * ->mmap() can change vma->vm_file and fput
2599 : * the original file. So fput the vma->vm_file
2600 : * here or we would add an extra fput for file
2601 : * and cause general protection fault
2602 : * ultimately.
2603 : */
2604 0 : fput(vma->vm_file);
2605 0 : vm_area_free(vma);
2606 0 : vma = merge;
2607 : /* Update vm_flags to pick up the change. */
2608 0 : vm_flags = vma->vm_flags;
2609 0 : goto unmap_writable;
2610 : }
2611 : }
2612 :
2613 0 : vm_flags = vma->vm_flags;
2614 0 : } else if (vm_flags & VM_SHARED) {
2615 0 : error = shmem_zero_setup(vma);
2616 0 : if (error)
2617 : goto free_vma;
2618 : } else {
2619 0 : vma_set_anonymous(vma);
2620 : }
2621 :
2622 0 : if (map_deny_write_exec(vma, vma->vm_flags)) {
2623 0 : error = -EACCES;
2624 0 : if (file)
2625 : goto close_and_free_vma;
2626 0 : else if (vma->vm_file)
2627 : goto unmap_and_free_vma;
2628 : else
2629 : goto free_vma;
2630 : }
2631 :
2632 : /* Allow architectures to sanity-check the vm_flags */
2633 0 : error = -EINVAL;
2634 0 : if (!arch_validate_flags(vma->vm_flags))
2635 : goto close_and_free_vma;
2636 :
2637 0 : error = -ENOMEM;
2638 0 : if (vma_iter_prealloc(&vmi))
2639 : goto close_and_free_vma;
2640 :
2641 0 : if (vma->vm_file)
2642 0 : i_mmap_lock_write(vma->vm_file->f_mapping);
2643 :
2644 0 : vma_iter_store(&vmi, vma);
2645 0 : mm->map_count++;
2646 0 : if (vma->vm_file) {
2647 0 : if (vma->vm_flags & VM_SHARED)
2648 0 : mapping_allow_writable(vma->vm_file->f_mapping);
2649 :
2650 0 : flush_dcache_mmap_lock(vma->vm_file->f_mapping);
2651 0 : vma_interval_tree_insert(vma, &vma->vm_file->f_mapping->i_mmap);
2652 0 : flush_dcache_mmap_unlock(vma->vm_file->f_mapping);
2653 0 : i_mmap_unlock_write(vma->vm_file->f_mapping);
2654 : }
2655 :
2656 : /*
2657 : * vma_merge() calls khugepaged_enter_vma() either, the below
2658 : * call covers the non-merge case.
2659 : */
2660 0 : khugepaged_enter_vma(vma, vma->vm_flags);
2661 :
2662 : /* Once vma denies write, undo our temporary denial count */
2663 : unmap_writable:
2664 0 : if (file && vm_flags & VM_SHARED)
2665 0 : mapping_unmap_writable(file->f_mapping);
2666 0 : file = vma->vm_file;
2667 : expanded:
2668 0 : perf_event_mmap(vma);
2669 :
2670 0 : vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT);
2671 0 : if (vm_flags & VM_LOCKED) {
2672 0 : if ((vm_flags & VM_SPECIAL) || vma_is_dax(vma) ||
2673 0 : is_vm_hugetlb_page(vma) ||
2674 0 : vma == get_gate_vma(current->mm))
2675 0 : vm_flags_clear(vma, VM_LOCKED_MASK);
2676 : else
2677 0 : mm->locked_vm += (len >> PAGE_SHIFT);
2678 : }
2679 :
2680 : if (file)
2681 : uprobe_mmap(vma);
2682 :
2683 : /*
2684 : * New (or expanded) vma always get soft dirty status.
2685 : * Otherwise user-space soft-dirty page tracker won't
2686 : * be able to distinguish situation when vma area unmapped,
2687 : * then new mapped in-place (which must be aimed as
2688 : * a completely new data area).
2689 : */
2690 0 : vm_flags_set(vma, VM_SOFTDIRTY);
2691 :
2692 0 : vma_set_page_prot(vma);
2693 :
2694 : validate_mm(mm);
2695 0 : return addr;
2696 :
2697 : close_and_free_vma:
2698 0 : if (file && vma->vm_ops && vma->vm_ops->close)
2699 0 : vma->vm_ops->close(vma);
2700 :
2701 0 : if (file || vma->vm_file) {
2702 : unmap_and_free_vma:
2703 0 : fput(vma->vm_file);
2704 0 : vma->vm_file = NULL;
2705 :
2706 : /* Undo any partial mapping done by a device driver. */
2707 0 : unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start,
2708 : vma->vm_end, true);
2709 : }
2710 0 : if (file && (vm_flags & VM_SHARED))
2711 0 : mapping_unmap_writable(file->f_mapping);
2712 : free_vma:
2713 0 : vm_area_free(vma);
2714 : unacct_error:
2715 0 : if (charged)
2716 0 : vm_unacct_memory(charged);
2717 : validate_mm(mm);
2718 0 : return error;
2719 : }
2720 :
2721 0 : static int __vm_munmap(unsigned long start, size_t len, bool downgrade)
2722 : {
2723 : int ret;
2724 0 : struct mm_struct *mm = current->mm;
2725 0 : LIST_HEAD(uf);
2726 0 : VMA_ITERATOR(vmi, mm, start);
2727 :
2728 0 : if (mmap_write_lock_killable(mm))
2729 : return -EINTR;
2730 :
2731 0 : ret = do_vmi_munmap(&vmi, mm, start, len, &uf, downgrade);
2732 : /*
2733 : * Returning 1 indicates mmap_lock is downgraded.
2734 : * But 1 is not legal return value of vm_munmap() and munmap(), reset
2735 : * it to 0 before return.
2736 : */
2737 0 : if (ret == 1) {
2738 0 : mmap_read_unlock(mm);
2739 0 : ret = 0;
2740 : } else
2741 : mmap_write_unlock(mm);
2742 :
2743 : userfaultfd_unmap_complete(mm, &uf);
2744 : return ret;
2745 : }
2746 :
2747 0 : int vm_munmap(unsigned long start, size_t len)
2748 : {
2749 0 : return __vm_munmap(start, len, false);
2750 : }
2751 : EXPORT_SYMBOL(vm_munmap);
2752 :
2753 0 : SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
2754 : {
2755 0 : addr = untagged_addr(addr);
2756 0 : return __vm_munmap(addr, len, true);
2757 : }
2758 :
2759 :
2760 : /*
2761 : * Emulation of deprecated remap_file_pages() syscall.
2762 : */
2763 0 : SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
2764 : unsigned long, prot, unsigned long, pgoff, unsigned long, flags)
2765 : {
2766 :
2767 0 : struct mm_struct *mm = current->mm;
2768 : struct vm_area_struct *vma;
2769 0 : unsigned long populate = 0;
2770 0 : unsigned long ret = -EINVAL;
2771 : struct file *file;
2772 :
2773 0 : pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. See Documentation/mm/remap_file_pages.rst.\n",
2774 : current->comm, current->pid);
2775 :
2776 0 : if (prot)
2777 : return ret;
2778 0 : start = start & PAGE_MASK;
2779 0 : size = size & PAGE_MASK;
2780 :
2781 0 : if (start + size <= start)
2782 : return ret;
2783 :
2784 : /* Does pgoff wrap? */
2785 0 : if (pgoff + (size >> PAGE_SHIFT) < pgoff)
2786 : return ret;
2787 :
2788 0 : if (mmap_write_lock_killable(mm))
2789 : return -EINTR;
2790 :
2791 0 : vma = vma_lookup(mm, start);
2792 :
2793 0 : if (!vma || !(vma->vm_flags & VM_SHARED))
2794 : goto out;
2795 :
2796 0 : if (start + size > vma->vm_end) {
2797 0 : VMA_ITERATOR(vmi, mm, vma->vm_end);
2798 0 : struct vm_area_struct *next, *prev = vma;
2799 :
2800 0 : for_each_vma_range(vmi, next, start + size) {
2801 : /* hole between vmas ? */
2802 0 : if (next->vm_start != prev->vm_end)
2803 : goto out;
2804 :
2805 0 : if (next->vm_file != vma->vm_file)
2806 : goto out;
2807 :
2808 0 : if (next->vm_flags != vma->vm_flags)
2809 : goto out;
2810 :
2811 0 : if (start + size <= next->vm_end)
2812 : break;
2813 :
2814 : prev = next;
2815 : }
2816 :
2817 0 : if (!next)
2818 : goto out;
2819 : }
2820 :
2821 0 : prot |= vma->vm_flags & VM_READ ? PROT_READ : 0;
2822 0 : prot |= vma->vm_flags & VM_WRITE ? PROT_WRITE : 0;
2823 0 : prot |= vma->vm_flags & VM_EXEC ? PROT_EXEC : 0;
2824 :
2825 0 : flags &= MAP_NONBLOCK;
2826 0 : flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE;
2827 0 : if (vma->vm_flags & VM_LOCKED)
2828 0 : flags |= MAP_LOCKED;
2829 :
2830 0 : file = get_file(vma->vm_file);
2831 0 : ret = do_mmap(vma->vm_file, start, size,
2832 : prot, flags, pgoff, &populate, NULL);
2833 0 : fput(file);
2834 : out:
2835 0 : mmap_write_unlock(mm);
2836 0 : if (populate)
2837 0 : mm_populate(ret, populate);
2838 0 : if (!IS_ERR_VALUE(ret))
2839 0 : ret = 0;
2840 0 : return ret;
2841 : }
2842 :
2843 : /*
2844 : * do_vma_munmap() - Unmap a full or partial vma.
2845 : * @vmi: The vma iterator pointing at the vma
2846 : * @vma: The first vma to be munmapped
2847 : * @start: the start of the address to unmap
2848 : * @end: The end of the address to unmap
2849 : * @uf: The userfaultfd list_head
2850 : * @downgrade: Attempt to downgrade or not
2851 : *
2852 : * Returns: 0 on success and not downgraded, 1 on success and downgraded.
2853 : * unmaps a VMA mapping when the vma iterator is already in position.
2854 : * Does not handle alignment.
2855 : */
2856 0 : int do_vma_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
2857 : unsigned long start, unsigned long end,
2858 : struct list_head *uf, bool downgrade)
2859 : {
2860 0 : struct mm_struct *mm = vma->vm_mm;
2861 : int ret;
2862 :
2863 0 : arch_unmap(mm, start, end);
2864 0 : ret = do_vmi_align_munmap(vmi, vma, mm, start, end, uf, downgrade);
2865 : validate_mm_mt(mm);
2866 0 : return ret;
2867 : }
2868 :
2869 : /*
2870 : * do_brk_flags() - Increase the brk vma if the flags match.
2871 : * @vmi: The vma iterator
2872 : * @addr: The start address
2873 : * @len: The length of the increase
2874 : * @vma: The vma,
2875 : * @flags: The VMA Flags
2876 : *
2877 : * Extend the brk VMA from addr to addr + len. If the VMA is NULL or the flags
2878 : * do not match then create a new anonymous VMA. Eventually we may be able to
2879 : * do some brk-specific accounting here.
2880 : */
2881 0 : static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
2882 : unsigned long addr, unsigned long len, unsigned long flags)
2883 : {
2884 0 : struct mm_struct *mm = current->mm;
2885 : struct vma_prepare vp;
2886 :
2887 : validate_mm_mt(mm);
2888 : /*
2889 : * Check against address space limits by the changed size
2890 : * Note: This happens *after* clearing old mappings in some code paths.
2891 : */
2892 0 : flags |= VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
2893 0 : if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT))
2894 : return -ENOMEM;
2895 :
2896 0 : if (mm->map_count > sysctl_max_map_count)
2897 : return -ENOMEM;
2898 :
2899 0 : if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT))
2900 : return -ENOMEM;
2901 :
2902 : /*
2903 : * Expand the existing vma if possible; Note that singular lists do not
2904 : * occur after forking, so the expand will only happen on new VMAs.
2905 : */
2906 0 : if (vma && vma->vm_end == addr && !vma_policy(vma) &&
2907 0 : can_vma_merge_after(vma, flags, NULL, NULL,
2908 : addr >> PAGE_SHIFT, NULL_VM_UFFD_CTX, NULL)) {
2909 0 : if (vma_iter_prealloc(vmi))
2910 : goto unacct_fail;
2911 :
2912 0 : vma_adjust_trans_huge(vma, vma->vm_start, addr + len, 0);
2913 0 : init_vma_prep(&vp, vma);
2914 0 : vma_prepare(&vp);
2915 0 : vma->vm_end = addr + len;
2916 0 : vm_flags_set(vma, VM_SOFTDIRTY);
2917 0 : vma_iter_store(vmi, vma);
2918 :
2919 0 : vma_complete(&vp, vmi, mm);
2920 0 : khugepaged_enter_vma(vma, flags);
2921 : goto out;
2922 : }
2923 :
2924 : /* create a vma struct for an anonymous mapping */
2925 0 : vma = vm_area_alloc(mm);
2926 0 : if (!vma)
2927 : goto unacct_fail;
2928 :
2929 0 : vma_set_anonymous(vma);
2930 0 : vma->vm_start = addr;
2931 0 : vma->vm_end = addr + len;
2932 0 : vma->vm_pgoff = addr >> PAGE_SHIFT;
2933 0 : vm_flags_init(vma, flags);
2934 0 : vma->vm_page_prot = vm_get_page_prot(flags);
2935 0 : if (vma_iter_store_gfp(vmi, vma, GFP_KERNEL))
2936 : goto mas_store_fail;
2937 :
2938 0 : mm->map_count++;
2939 : out:
2940 0 : perf_event_mmap(vma);
2941 0 : mm->total_vm += len >> PAGE_SHIFT;
2942 0 : mm->data_vm += len >> PAGE_SHIFT;
2943 0 : if (flags & VM_LOCKED)
2944 0 : mm->locked_vm += (len >> PAGE_SHIFT);
2945 0 : vm_flags_set(vma, VM_SOFTDIRTY);
2946 : validate_mm(mm);
2947 0 : return 0;
2948 :
2949 : mas_store_fail:
2950 0 : vm_area_free(vma);
2951 : unacct_fail:
2952 0 : vm_unacct_memory(len >> PAGE_SHIFT);
2953 0 : return -ENOMEM;
2954 : }
2955 :
2956 0 : int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags)
2957 : {
2958 0 : struct mm_struct *mm = current->mm;
2959 0 : struct vm_area_struct *vma = NULL;
2960 : unsigned long len;
2961 : int ret;
2962 : bool populate;
2963 0 : LIST_HEAD(uf);
2964 0 : VMA_ITERATOR(vmi, mm, addr);
2965 :
2966 0 : len = PAGE_ALIGN(request);
2967 0 : if (len < request)
2968 : return -ENOMEM;
2969 0 : if (!len)
2970 : return 0;
2971 :
2972 0 : if (mmap_write_lock_killable(mm))
2973 : return -EINTR;
2974 :
2975 : /* Until we need other flags, refuse anything except VM_EXEC. */
2976 0 : if ((flags & (~VM_EXEC)) != 0)
2977 : return -EINVAL;
2978 :
2979 0 : ret = check_brk_limits(addr, len);
2980 0 : if (ret)
2981 : goto limits_failed;
2982 :
2983 0 : ret = do_vmi_munmap(&vmi, mm, addr, len, &uf, 0);
2984 0 : if (ret)
2985 : goto munmap_failed;
2986 :
2987 0 : vma = vma_prev(&vmi);
2988 0 : ret = do_brk_flags(&vmi, vma, addr, len, flags);
2989 0 : populate = ((mm->def_flags & VM_LOCKED) != 0);
2990 0 : mmap_write_unlock(mm);
2991 0 : userfaultfd_unmap_complete(mm, &uf);
2992 0 : if (populate && !ret)
2993 : mm_populate(addr, len);
2994 : return ret;
2995 :
2996 : munmap_failed:
2997 : limits_failed:
2998 0 : mmap_write_unlock(mm);
2999 0 : return ret;
3000 : }
3001 : EXPORT_SYMBOL(vm_brk_flags);
3002 :
3003 0 : int vm_brk(unsigned long addr, unsigned long len)
3004 : {
3005 0 : return vm_brk_flags(addr, len, 0);
3006 : }
3007 : EXPORT_SYMBOL(vm_brk);
3008 :
3009 : /* Release all mmaps. */
3010 0 : void exit_mmap(struct mm_struct *mm)
3011 : {
3012 : struct mmu_gather tlb;
3013 : struct vm_area_struct *vma;
3014 0 : unsigned long nr_accounted = 0;
3015 0 : MA_STATE(mas, &mm->mm_mt, 0, 0);
3016 0 : int count = 0;
3017 :
3018 : /* mm's last user has gone, and its about to be pulled down */
3019 0 : mmu_notifier_release(mm);
3020 :
3021 0 : mmap_read_lock(mm);
3022 0 : arch_exit_mmap(mm);
3023 :
3024 0 : vma = mas_find(&mas, ULONG_MAX);
3025 0 : if (!vma) {
3026 : /* Can happen if dup_mmap() received an OOM */
3027 0 : mmap_read_unlock(mm);
3028 0 : return;
3029 : }
3030 :
3031 0 : lru_add_drain();
3032 0 : flush_cache_mm(mm);
3033 0 : tlb_gather_mmu_fullmm(&tlb, mm);
3034 : /* update_hiwater_rss(mm) here? but nobody should be looking */
3035 : /* Use ULONG_MAX here to ensure all VMAs in the mm are unmapped */
3036 0 : unmap_vmas(&tlb, &mm->mm_mt, vma, 0, ULONG_MAX, false);
3037 0 : mmap_read_unlock(mm);
3038 :
3039 : /*
3040 : * Set MMF_OOM_SKIP to hide this task from the oom killer/reaper
3041 : * because the memory has been already freed.
3042 : */
3043 0 : set_bit(MMF_OOM_SKIP, &mm->flags);
3044 0 : mmap_write_lock(mm);
3045 0 : free_pgtables(&tlb, &mm->mm_mt, vma, FIRST_USER_ADDRESS,
3046 : USER_PGTABLES_CEILING);
3047 0 : tlb_finish_mmu(&tlb);
3048 :
3049 : /*
3050 : * Walk the list again, actually closing and freeing it, with preemption
3051 : * enabled, without holding any MM locks besides the unreachable
3052 : * mmap_write_lock.
3053 : */
3054 : do {
3055 0 : if (vma->vm_flags & VM_ACCOUNT)
3056 0 : nr_accounted += vma_pages(vma);
3057 0 : remove_vma(vma);
3058 0 : count++;
3059 0 : cond_resched();
3060 0 : } while ((vma = mas_find(&mas, ULONG_MAX)) != NULL);
3061 :
3062 0 : BUG_ON(count != mm->map_count);
3063 :
3064 0 : trace_exit_mmap(mm);
3065 0 : __mt_destroy(&mm->mm_mt);
3066 0 : mmap_write_unlock(mm);
3067 0 : vm_unacct_memory(nr_accounted);
3068 : }
3069 :
3070 : /* Insert vm structure into process list sorted by address
3071 : * and into the inode's i_mmap tree. If vm_file is non-NULL
3072 : * then i_mmap_rwsem is taken here.
3073 : */
3074 0 : int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
3075 : {
3076 0 : unsigned long charged = vma_pages(vma);
3077 :
3078 :
3079 0 : if (find_vma_intersection(mm, vma->vm_start, vma->vm_end))
3080 : return -ENOMEM;
3081 :
3082 0 : if ((vma->vm_flags & VM_ACCOUNT) &&
3083 0 : security_vm_enough_memory_mm(mm, charged))
3084 : return -ENOMEM;
3085 :
3086 : /*
3087 : * The vm_pgoff of a purely anonymous vma should be irrelevant
3088 : * until its first write fault, when page's anon_vma and index
3089 : * are set. But now set the vm_pgoff it will almost certainly
3090 : * end up with (unless mremap moves it elsewhere before that
3091 : * first wfault), so /proc/pid/maps tells a consistent story.
3092 : *
3093 : * By setting it to reflect the virtual start address of the
3094 : * vma, merges and splits can happen in a seamless way, just
3095 : * using the existing file pgoff checks and manipulations.
3096 : * Similarly in do_mmap and in do_brk_flags.
3097 : */
3098 0 : if (vma_is_anonymous(vma)) {
3099 0 : BUG_ON(vma->anon_vma);
3100 0 : vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
3101 : }
3102 :
3103 0 : if (vma_link(mm, vma)) {
3104 0 : vm_unacct_memory(charged);
3105 0 : return -ENOMEM;
3106 : }
3107 :
3108 : return 0;
3109 : }
3110 :
3111 : /*
3112 : * Copy the vma structure to a new location in the same mm,
3113 : * prior to moving page table entries, to effect an mremap move.
3114 : */
3115 0 : struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
3116 : unsigned long addr, unsigned long len, pgoff_t pgoff,
3117 : bool *need_rmap_locks)
3118 : {
3119 0 : struct vm_area_struct *vma = *vmap;
3120 0 : unsigned long vma_start = vma->vm_start;
3121 0 : struct mm_struct *mm = vma->vm_mm;
3122 : struct vm_area_struct *new_vma, *prev;
3123 0 : bool faulted_in_anon_vma = true;
3124 0 : VMA_ITERATOR(vmi, mm, addr);
3125 :
3126 : validate_mm_mt(mm);
3127 : /*
3128 : * If anonymous vma has not yet been faulted, update new pgoff
3129 : * to match new location, to increase its chance of merging.
3130 : */
3131 0 : if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) {
3132 0 : pgoff = addr >> PAGE_SHIFT;
3133 0 : faulted_in_anon_vma = false;
3134 : }
3135 :
3136 0 : new_vma = find_vma_prev(mm, addr, &prev);
3137 0 : if (new_vma && new_vma->vm_start < addr + len)
3138 : return NULL; /* should never get here */
3139 :
3140 0 : new_vma = vma_merge(&vmi, mm, prev, addr, addr + len, vma->vm_flags,
3141 : vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
3142 : vma->vm_userfaultfd_ctx, anon_vma_name(vma));
3143 0 : if (new_vma) {
3144 : /*
3145 : * Source vma may have been merged into new_vma
3146 : */
3147 0 : if (unlikely(vma_start >= new_vma->vm_start &&
3148 : vma_start < new_vma->vm_end)) {
3149 : /*
3150 : * The only way we can get a vma_merge with
3151 : * self during an mremap is if the vma hasn't
3152 : * been faulted in yet and we were allowed to
3153 : * reset the dst vma->vm_pgoff to the
3154 : * destination address of the mremap to allow
3155 : * the merge to happen. mremap must change the
3156 : * vm_pgoff linearity between src and dst vmas
3157 : * (in turn preventing a vma_merge) to be
3158 : * safe. It is only safe to keep the vm_pgoff
3159 : * linear if there are no pages mapped yet.
3160 : */
3161 : VM_BUG_ON_VMA(faulted_in_anon_vma, new_vma);
3162 0 : *vmap = vma = new_vma;
3163 : }
3164 0 : *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff);
3165 : } else {
3166 0 : new_vma = vm_area_dup(vma);
3167 0 : if (!new_vma)
3168 : goto out;
3169 0 : new_vma->vm_start = addr;
3170 0 : new_vma->vm_end = addr + len;
3171 0 : new_vma->vm_pgoff = pgoff;
3172 0 : if (vma_dup_policy(vma, new_vma))
3173 : goto out_free_vma;
3174 0 : if (anon_vma_clone(new_vma, vma))
3175 : goto out_free_mempol;
3176 0 : if (new_vma->vm_file)
3177 0 : get_file(new_vma->vm_file);
3178 0 : if (new_vma->vm_ops && new_vma->vm_ops->open)
3179 0 : new_vma->vm_ops->open(new_vma);
3180 0 : if (vma_link(mm, new_vma))
3181 : goto out_vma_link;
3182 0 : *need_rmap_locks = false;
3183 : }
3184 : validate_mm_mt(mm);
3185 : return new_vma;
3186 :
3187 : out_vma_link:
3188 0 : if (new_vma->vm_ops && new_vma->vm_ops->close)
3189 0 : new_vma->vm_ops->close(new_vma);
3190 :
3191 0 : if (new_vma->vm_file)
3192 0 : fput(new_vma->vm_file);
3193 :
3194 0 : unlink_anon_vmas(new_vma);
3195 : out_free_mempol:
3196 0 : mpol_put(vma_policy(new_vma));
3197 : out_free_vma:
3198 0 : vm_area_free(new_vma);
3199 : out:
3200 : validate_mm_mt(mm);
3201 : return NULL;
3202 : }
3203 :
3204 : /*
3205 : * Return true if the calling process may expand its vm space by the passed
3206 : * number of pages
3207 : */
3208 0 : bool may_expand_vm(struct mm_struct *mm, vm_flags_t flags, unsigned long npages)
3209 : {
3210 0 : if (mm->total_vm + npages > rlimit(RLIMIT_AS) >> PAGE_SHIFT)
3211 : return false;
3212 :
3213 0 : if (is_data_mapping(flags) &&
3214 0 : mm->data_vm + npages > rlimit(RLIMIT_DATA) >> PAGE_SHIFT) {
3215 : /* Workaround for Valgrind */
3216 0 : if (rlimit(RLIMIT_DATA) == 0 &&
3217 0 : mm->data_vm + npages <= rlimit_max(RLIMIT_DATA) >> PAGE_SHIFT)
3218 : return true;
3219 :
3220 0 : pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits%s.\n",
3221 : current->comm, current->pid,
3222 : (mm->data_vm + npages) << PAGE_SHIFT,
3223 : rlimit(RLIMIT_DATA),
3224 : ignore_rlimit_data ? "" : " or use boot option ignore_rlimit_data");
3225 :
3226 0 : if (!ignore_rlimit_data)
3227 : return false;
3228 : }
3229 :
3230 : return true;
3231 : }
3232 :
3233 0 : void vm_stat_account(struct mm_struct *mm, vm_flags_t flags, long npages)
3234 : {
3235 0 : WRITE_ONCE(mm->total_vm, READ_ONCE(mm->total_vm)+npages);
3236 :
3237 0 : if (is_exec_mapping(flags))
3238 0 : mm->exec_vm += npages;
3239 0 : else if (is_stack_mapping(flags))
3240 0 : mm->stack_vm += npages;
3241 0 : else if (is_data_mapping(flags))
3242 0 : mm->data_vm += npages;
3243 0 : }
3244 :
3245 : static vm_fault_t special_mapping_fault(struct vm_fault *vmf);
3246 :
3247 : /*
3248 : * Having a close hook prevents vma merging regardless of flags.
3249 : */
3250 0 : static void special_mapping_close(struct vm_area_struct *vma)
3251 : {
3252 0 : }
3253 :
3254 0 : static const char *special_mapping_name(struct vm_area_struct *vma)
3255 : {
3256 0 : return ((struct vm_special_mapping *)vma->vm_private_data)->name;
3257 : }
3258 :
3259 0 : static int special_mapping_mremap(struct vm_area_struct *new_vma)
3260 : {
3261 0 : struct vm_special_mapping *sm = new_vma->vm_private_data;
3262 :
3263 0 : if (WARN_ON_ONCE(current->mm != new_vma->vm_mm))
3264 : return -EFAULT;
3265 :
3266 0 : if (sm->mremap)
3267 0 : return sm->mremap(sm, new_vma);
3268 :
3269 : return 0;
3270 : }
3271 :
3272 0 : static int special_mapping_split(struct vm_area_struct *vma, unsigned long addr)
3273 : {
3274 : /*
3275 : * Forbid splitting special mappings - kernel has expectations over
3276 : * the number of pages in mapping. Together with VM_DONTEXPAND
3277 : * the size of vma should stay the same over the special mapping's
3278 : * lifetime.
3279 : */
3280 0 : return -EINVAL;
3281 : }
3282 :
3283 : static const struct vm_operations_struct special_mapping_vmops = {
3284 : .close = special_mapping_close,
3285 : .fault = special_mapping_fault,
3286 : .mremap = special_mapping_mremap,
3287 : .name = special_mapping_name,
3288 : /* vDSO code relies that VVAR can't be accessed remotely */
3289 : .access = NULL,
3290 : .may_split = special_mapping_split,
3291 : };
3292 :
3293 : static const struct vm_operations_struct legacy_special_mapping_vmops = {
3294 : .close = special_mapping_close,
3295 : .fault = special_mapping_fault,
3296 : };
3297 :
3298 0 : static vm_fault_t special_mapping_fault(struct vm_fault *vmf)
3299 : {
3300 0 : struct vm_area_struct *vma = vmf->vma;
3301 : pgoff_t pgoff;
3302 : struct page **pages;
3303 :
3304 0 : if (vma->vm_ops == &legacy_special_mapping_vmops) {
3305 0 : pages = vma->vm_private_data;
3306 : } else {
3307 0 : struct vm_special_mapping *sm = vma->vm_private_data;
3308 :
3309 0 : if (sm->fault)
3310 0 : return sm->fault(sm, vmf->vma, vmf);
3311 :
3312 0 : pages = sm->pages;
3313 : }
3314 :
3315 0 : for (pgoff = vmf->pgoff; pgoff && *pages; ++pages)
3316 0 : pgoff--;
3317 :
3318 0 : if (*pages) {
3319 0 : struct page *page = *pages;
3320 0 : get_page(page);
3321 0 : vmf->page = page;
3322 0 : return 0;
3323 : }
3324 :
3325 : return VM_FAULT_SIGBUS;
3326 : }
3327 :
3328 0 : static struct vm_area_struct *__install_special_mapping(
3329 : struct mm_struct *mm,
3330 : unsigned long addr, unsigned long len,
3331 : unsigned long vm_flags, void *priv,
3332 : const struct vm_operations_struct *ops)
3333 : {
3334 : int ret;
3335 : struct vm_area_struct *vma;
3336 :
3337 : validate_mm_mt(mm);
3338 0 : vma = vm_area_alloc(mm);
3339 0 : if (unlikely(vma == NULL))
3340 : return ERR_PTR(-ENOMEM);
3341 :
3342 0 : vma->vm_start = addr;
3343 0 : vma->vm_end = addr + len;
3344 :
3345 0 : vm_flags_init(vma, (vm_flags | mm->def_flags |
3346 0 : VM_DONTEXPAND | VM_SOFTDIRTY) & ~VM_LOCKED_MASK);
3347 0 : vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
3348 :
3349 0 : vma->vm_ops = ops;
3350 0 : vma->vm_private_data = priv;
3351 :
3352 0 : ret = insert_vm_struct(mm, vma);
3353 0 : if (ret)
3354 : goto out;
3355 :
3356 0 : vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT);
3357 :
3358 : perf_event_mmap(vma);
3359 :
3360 : validate_mm_mt(mm);
3361 : return vma;
3362 :
3363 : out:
3364 0 : vm_area_free(vma);
3365 : validate_mm_mt(mm);
3366 0 : return ERR_PTR(ret);
3367 : }
3368 :
3369 0 : bool vma_is_special_mapping(const struct vm_area_struct *vma,
3370 : const struct vm_special_mapping *sm)
3371 : {
3372 0 : return vma->vm_private_data == sm &&
3373 0 : (vma->vm_ops == &special_mapping_vmops ||
3374 : vma->vm_ops == &legacy_special_mapping_vmops);
3375 : }
3376 :
3377 : /*
3378 : * Called with mm->mmap_lock held for writing.
3379 : * Insert a new vma covering the given region, with the given flags.
3380 : * Its pages are supplied by the given array of struct page *.
3381 : * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
3382 : * The region past the last page supplied will always produce SIGBUS.
3383 : * The array pointer and the pages it points to are assumed to stay alive
3384 : * for as long as this mapping might exist.
3385 : */
3386 0 : struct vm_area_struct *_install_special_mapping(
3387 : struct mm_struct *mm,
3388 : unsigned long addr, unsigned long len,
3389 : unsigned long vm_flags, const struct vm_special_mapping *spec)
3390 : {
3391 0 : return __install_special_mapping(mm, addr, len, vm_flags, (void *)spec,
3392 : &special_mapping_vmops);
3393 : }
3394 :
3395 0 : int install_special_mapping(struct mm_struct *mm,
3396 : unsigned long addr, unsigned long len,
3397 : unsigned long vm_flags, struct page **pages)
3398 : {
3399 0 : struct vm_area_struct *vma = __install_special_mapping(
3400 : mm, addr, len, vm_flags, (void *)pages,
3401 : &legacy_special_mapping_vmops);
3402 :
3403 0 : return PTR_ERR_OR_ZERO(vma);
3404 : }
3405 :
3406 : static DEFINE_MUTEX(mm_all_locks_mutex);
3407 :
3408 0 : static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
3409 : {
3410 0 : if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) {
3411 : /*
3412 : * The LSB of head.next can't change from under us
3413 : * because we hold the mm_all_locks_mutex.
3414 : */
3415 0 : down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_lock);
3416 : /*
3417 : * We can safely modify head.next after taking the
3418 : * anon_vma->root->rwsem. If some other vma in this mm shares
3419 : * the same anon_vma we won't take it again.
3420 : *
3421 : * No need of atomic instructions here, head.next
3422 : * can't change from under us thanks to the
3423 : * anon_vma->root->rwsem.
3424 : */
3425 0 : if (__test_and_set_bit(0, (unsigned long *)
3426 : &anon_vma->root->rb_root.rb_root.rb_node))
3427 0 : BUG();
3428 : }
3429 0 : }
3430 :
3431 0 : static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
3432 : {
3433 0 : if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
3434 : /*
3435 : * AS_MM_ALL_LOCKS can't change from under us because
3436 : * we hold the mm_all_locks_mutex.
3437 : *
3438 : * Operations on ->flags have to be atomic because
3439 : * even if AS_MM_ALL_LOCKS is stable thanks to the
3440 : * mm_all_locks_mutex, there may be other cpus
3441 : * changing other bitflags in parallel to us.
3442 : */
3443 0 : if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
3444 0 : BUG();
3445 0 : down_write_nest_lock(&mapping->i_mmap_rwsem, &mm->mmap_lock);
3446 : }
3447 0 : }
3448 :
3449 : /*
3450 : * This operation locks against the VM for all pte/vma/mm related
3451 : * operations that could ever happen on a certain mm. This includes
3452 : * vmtruncate, try_to_unmap, and all page faults.
3453 : *
3454 : * The caller must take the mmap_lock in write mode before calling
3455 : * mm_take_all_locks(). The caller isn't allowed to release the
3456 : * mmap_lock until mm_drop_all_locks() returns.
3457 : *
3458 : * mmap_lock in write mode is required in order to block all operations
3459 : * that could modify pagetables and free pages without need of
3460 : * altering the vma layout. It's also needed in write mode to avoid new
3461 : * anon_vmas to be associated with existing vmas.
3462 : *
3463 : * A single task can't take more than one mm_take_all_locks() in a row
3464 : * or it would deadlock.
3465 : *
3466 : * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in
3467 : * mapping->flags avoid to take the same lock twice, if more than one
3468 : * vma in this mm is backed by the same anon_vma or address_space.
3469 : *
3470 : * We take locks in following order, accordingly to comment at beginning
3471 : * of mm/rmap.c:
3472 : * - all hugetlbfs_i_mmap_rwsem_key locks (aka mapping->i_mmap_rwsem for
3473 : * hugetlb mapping);
3474 : * - all i_mmap_rwsem locks;
3475 : * - all anon_vma->rwseml
3476 : *
3477 : * We can take all locks within these types randomly because the VM code
3478 : * doesn't nest them and we protected from parallel mm_take_all_locks() by
3479 : * mm_all_locks_mutex.
3480 : *
3481 : * mm_take_all_locks() and mm_drop_all_locks are expensive operations
3482 : * that may have to take thousand of locks.
3483 : *
3484 : * mm_take_all_locks() can fail if it's interrupted by signals.
3485 : */
3486 0 : int mm_take_all_locks(struct mm_struct *mm)
3487 : {
3488 : struct vm_area_struct *vma;
3489 : struct anon_vma_chain *avc;
3490 0 : MA_STATE(mas, &mm->mm_mt, 0, 0);
3491 :
3492 0 : mmap_assert_write_locked(mm);
3493 :
3494 0 : mutex_lock(&mm_all_locks_mutex);
3495 :
3496 0 : mas_for_each(&mas, vma, ULONG_MAX) {
3497 0 : if (signal_pending(current))
3498 : goto out_unlock;
3499 : if (vma->vm_file && vma->vm_file->f_mapping &&
3500 : is_vm_hugetlb_page(vma))
3501 : vm_lock_mapping(mm, vma->vm_file->f_mapping);
3502 : }
3503 :
3504 : mas_set(&mas, 0);
3505 0 : mas_for_each(&mas, vma, ULONG_MAX) {
3506 0 : if (signal_pending(current))
3507 : goto out_unlock;
3508 0 : if (vma->vm_file && vma->vm_file->f_mapping &&
3509 0 : !is_vm_hugetlb_page(vma))
3510 0 : vm_lock_mapping(mm, vma->vm_file->f_mapping);
3511 : }
3512 :
3513 : mas_set(&mas, 0);
3514 0 : mas_for_each(&mas, vma, ULONG_MAX) {
3515 0 : if (signal_pending(current))
3516 : goto out_unlock;
3517 0 : if (vma->anon_vma)
3518 0 : list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
3519 0 : vm_lock_anon_vma(mm, avc->anon_vma);
3520 : }
3521 :
3522 : return 0;
3523 :
3524 : out_unlock:
3525 0 : mm_drop_all_locks(mm);
3526 0 : return -EINTR;
3527 : }
3528 :
3529 0 : static void vm_unlock_anon_vma(struct anon_vma *anon_vma)
3530 : {
3531 0 : if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) {
3532 : /*
3533 : * The LSB of head.next can't change to 0 from under
3534 : * us because we hold the mm_all_locks_mutex.
3535 : *
3536 : * We must however clear the bitflag before unlocking
3537 : * the vma so the users using the anon_vma->rb_root will
3538 : * never see our bitflag.
3539 : *
3540 : * No need of atomic instructions here, head.next
3541 : * can't change from under us until we release the
3542 : * anon_vma->root->rwsem.
3543 : */
3544 0 : if (!__test_and_clear_bit(0, (unsigned long *)
3545 : &anon_vma->root->rb_root.rb_root.rb_node))
3546 0 : BUG();
3547 0 : anon_vma_unlock_write(anon_vma);
3548 : }
3549 0 : }
3550 :
3551 0 : static void vm_unlock_mapping(struct address_space *mapping)
3552 : {
3553 0 : if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
3554 : /*
3555 : * AS_MM_ALL_LOCKS can't change to 0 from under us
3556 : * because we hold the mm_all_locks_mutex.
3557 : */
3558 0 : i_mmap_unlock_write(mapping);
3559 0 : if (!test_and_clear_bit(AS_MM_ALL_LOCKS,
3560 0 : &mapping->flags))
3561 0 : BUG();
3562 : }
3563 0 : }
3564 :
3565 : /*
3566 : * The mmap_lock cannot be released by the caller until
3567 : * mm_drop_all_locks() returns.
3568 : */
3569 0 : void mm_drop_all_locks(struct mm_struct *mm)
3570 : {
3571 : struct vm_area_struct *vma;
3572 : struct anon_vma_chain *avc;
3573 0 : MA_STATE(mas, &mm->mm_mt, 0, 0);
3574 :
3575 0 : mmap_assert_write_locked(mm);
3576 0 : BUG_ON(!mutex_is_locked(&mm_all_locks_mutex));
3577 :
3578 0 : mas_for_each(&mas, vma, ULONG_MAX) {
3579 0 : if (vma->anon_vma)
3580 0 : list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
3581 0 : vm_unlock_anon_vma(avc->anon_vma);
3582 0 : if (vma->vm_file && vma->vm_file->f_mapping)
3583 0 : vm_unlock_mapping(vma->vm_file->f_mapping);
3584 : }
3585 :
3586 0 : mutex_unlock(&mm_all_locks_mutex);
3587 0 : }
3588 :
3589 : /*
3590 : * initialise the percpu counter for VM
3591 : */
3592 1 : void __init mmap_init(void)
3593 : {
3594 : int ret;
3595 :
3596 2 : ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
3597 : VM_BUG_ON(ret);
3598 1 : }
3599 :
3600 : /*
3601 : * Initialise sysctl_user_reserve_kbytes.
3602 : *
3603 : * This is intended to prevent a user from starting a single memory hogging
3604 : * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
3605 : * mode.
3606 : *
3607 : * The default value is min(3% of free memory, 128MB)
3608 : * 128MB is enough to recover with sshd/login, bash, and top/kill.
3609 : */
3610 1 : static int init_user_reserve(void)
3611 : {
3612 : unsigned long free_kbytes;
3613 :
3614 1 : free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
3615 :
3616 1 : sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
3617 1 : return 0;
3618 : }
3619 : subsys_initcall(init_user_reserve);
3620 :
3621 : /*
3622 : * Initialise sysctl_admin_reserve_kbytes.
3623 : *
3624 : * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
3625 : * to log in and kill a memory hogging process.
3626 : *
3627 : * Systems with more than 256MB will reserve 8MB, enough to recover
3628 : * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
3629 : * only reserve 3% of free pages by default.
3630 : */
3631 1 : static int init_admin_reserve(void)
3632 : {
3633 : unsigned long free_kbytes;
3634 :
3635 1 : free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
3636 :
3637 1 : sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
3638 1 : return 0;
3639 : }
3640 : subsys_initcall(init_admin_reserve);
3641 :
3642 : /*
3643 : * Reinititalise user and admin reserves if memory is added or removed.
3644 : *
3645 : * The default user reserve max is 128MB, and the default max for the
3646 : * admin reserve is 8MB. These are usually, but not always, enough to
3647 : * enable recovery from a memory hogging process using login/sshd, a shell,
3648 : * and tools like top. It may make sense to increase or even disable the
3649 : * reserve depending on the existence of swap or variations in the recovery
3650 : * tools. So, the admin may have changed them.
3651 : *
3652 : * If memory is added and the reserves have been eliminated or increased above
3653 : * the default max, then we'll trust the admin.
3654 : *
3655 : * If memory is removed and there isn't enough free memory, then we
3656 : * need to reset the reserves.
3657 : *
3658 : * Otherwise keep the reserve set by the admin.
3659 : */
3660 : static int reserve_mem_notifier(struct notifier_block *nb,
3661 : unsigned long action, void *data)
3662 : {
3663 : unsigned long tmp, free_kbytes;
3664 :
3665 : switch (action) {
3666 : case MEM_ONLINE:
3667 : /* Default max is 128MB. Leave alone if modified by operator. */
3668 : tmp = sysctl_user_reserve_kbytes;
3669 : if (0 < tmp && tmp < (1UL << 17))
3670 : init_user_reserve();
3671 :
3672 : /* Default max is 8MB. Leave alone if modified by operator. */
3673 : tmp = sysctl_admin_reserve_kbytes;
3674 : if (0 < tmp && tmp < (1UL << 13))
3675 : init_admin_reserve();
3676 :
3677 : break;
3678 : case MEM_OFFLINE:
3679 : free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
3680 :
3681 : if (sysctl_user_reserve_kbytes > free_kbytes) {
3682 : init_user_reserve();
3683 : pr_info("vm.user_reserve_kbytes reset to %lu\n",
3684 : sysctl_user_reserve_kbytes);
3685 : }
3686 :
3687 : if (sysctl_admin_reserve_kbytes > free_kbytes) {
3688 : init_admin_reserve();
3689 : pr_info("vm.admin_reserve_kbytes reset to %lu\n",
3690 : sysctl_admin_reserve_kbytes);
3691 : }
3692 : break;
3693 : default:
3694 : break;
3695 : }
3696 : return NOTIFY_OK;
3697 : }
3698 :
3699 1 : static int __meminit init_reserve_notifier(void)
3700 : {
3701 1 : if (hotplug_memory_notifier(reserve_mem_notifier, DEFAULT_CALLBACK_PRI))
3702 : pr_err("Failed registering memory add/remove notifier for admin reserve\n");
3703 :
3704 1 : return 0;
3705 : }
3706 : subsys_initcall(init_reserve_notifier);
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