1 // SPDX-License-Identifier: GPL-2.0-only
7 * Address space accounting code <alan@lxorguk.ukuu.org.uk>
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12 #include <linux/kernel.h>
13 #include <linux/slab.h>
14 #include <linux/backing-dev.h>
16 #include <linux/vmacache.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>
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/rbtree_augmented.h>
42 #include <linux/notifier.h>
43 #include <linux/memory.h>
44 #include <linux/printk.h>
45 #include <linux/userfaultfd_k.h>
46 #include <linux/moduleparam.h>
47 #include <linux/pkeys.h>
48 #include <linux/oom.h>
49 #include <linux/sched/mm.h>
51 #include <linux/uaccess.h>
52 #include <asm/cacheflush.h>
54 #include <asm/mmu_context.h>
58 #ifndef arch_mmap_check
59 #define arch_mmap_check(addr, len, flags) (0)
62 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
63 const int mmap_rnd_bits_min
= CONFIG_ARCH_MMAP_RND_BITS_MIN
;
64 const int mmap_rnd_bits_max
= CONFIG_ARCH_MMAP_RND_BITS_MAX
;
65 int mmap_rnd_bits __read_mostly
= CONFIG_ARCH_MMAP_RND_BITS
;
67 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
68 const int mmap_rnd_compat_bits_min
= CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MIN
;
69 const int mmap_rnd_compat_bits_max
= CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MAX
;
70 int mmap_rnd_compat_bits __read_mostly
= CONFIG_ARCH_MMAP_RND_COMPAT_BITS
;
73 static bool ignore_rlimit_data
;
74 core_param(ignore_rlimit_data
, ignore_rlimit_data
, bool, 0644);
76 static void unmap_region(struct mm_struct
*mm
,
77 struct vm_area_struct
*vma
, struct vm_area_struct
*prev
,
78 unsigned long start
, unsigned long end
);
80 /* description of effects of mapping type and prot in current implementation.
81 * this is due to the limited x86 page protection hardware. The expected
82 * behavior is in parens:
85 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
86 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
87 * w: (no) no w: (no) no w: (yes) yes w: (no) no
88 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
90 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
91 * w: (no) no w: (no) no w: (copy) copy w: (no) no
92 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
94 * On arm64, PROT_EXEC has the following behaviour for both MAP_SHARED and
100 pgprot_t protection_map
[16] __ro_after_init
= {
101 __P000
, __P001
, __P010
, __P011
, __P100
, __P101
, __P110
, __P111
,
102 __S000
, __S001
, __S010
, __S011
, __S100
, __S101
, __S110
, __S111
105 #ifndef CONFIG_ARCH_HAS_FILTER_PGPROT
106 static inline pgprot_t
arch_filter_pgprot(pgprot_t prot
)
112 pgprot_t
vm_get_page_prot(unsigned long vm_flags
)
114 pgprot_t ret
= __pgprot(pgprot_val(protection_map
[vm_flags
&
115 (VM_READ
|VM_WRITE
|VM_EXEC
|VM_SHARED
)]) |
116 pgprot_val(arch_vm_get_page_prot(vm_flags
)));
118 return arch_filter_pgprot(ret
);
120 EXPORT_SYMBOL(vm_get_page_prot
);
122 static pgprot_t
vm_pgprot_modify(pgprot_t oldprot
, unsigned long vm_flags
)
124 return pgprot_modify(oldprot
, vm_get_page_prot(vm_flags
));
127 /* Update vma->vm_page_prot to reflect vma->vm_flags. */
128 void vma_set_page_prot(struct vm_area_struct
*vma
)
130 unsigned long vm_flags
= vma
->vm_flags
;
131 pgprot_t vm_page_prot
;
133 vm_page_prot
= vm_pgprot_modify(vma
->vm_page_prot
, vm_flags
);
134 if (vma_wants_writenotify(vma
, vm_page_prot
)) {
135 vm_flags
&= ~VM_SHARED
;
136 vm_page_prot
= vm_pgprot_modify(vm_page_prot
, vm_flags
);
138 /* remove_protection_ptes reads vma->vm_page_prot without mmap_sem */
139 WRITE_ONCE(vma
->vm_page_prot
, vm_page_prot
);
143 * Requires inode->i_mapping->i_mmap_rwsem
145 static void __remove_shared_vm_struct(struct vm_area_struct
*vma
,
146 struct file
*file
, struct address_space
*mapping
)
148 if (vma
->vm_flags
& VM_DENYWRITE
)
149 atomic_inc(&file_inode(file
)->i_writecount
);
150 if (vma
->vm_flags
& VM_SHARED
)
151 mapping_unmap_writable(mapping
);
153 flush_dcache_mmap_lock(mapping
);
154 vma_interval_tree_remove(vma
, &mapping
->i_mmap
);
155 flush_dcache_mmap_unlock(mapping
);
159 * Unlink a file-based vm structure from its interval tree, to hide
160 * vma from rmap and vmtruncate before freeing its page tables.
162 void unlink_file_vma(struct vm_area_struct
*vma
)
164 struct file
*file
= vma
->vm_file
;
167 struct address_space
*mapping
= file
->f_mapping
;
168 i_mmap_lock_write(mapping
);
169 __remove_shared_vm_struct(vma
, file
, mapping
);
170 i_mmap_unlock_write(mapping
);
175 * Close a vm structure and free it, returning the next.
177 static struct vm_area_struct
*remove_vma(struct vm_area_struct
*vma
)
179 struct vm_area_struct
*next
= vma
->vm_next
;
182 if (vma
->vm_ops
&& vma
->vm_ops
->close
)
183 vma
->vm_ops
->close(vma
);
186 mpol_put(vma_policy(vma
));
191 static int do_brk_flags(unsigned long addr
, unsigned long request
, unsigned long flags
,
192 struct list_head
*uf
);
193 SYSCALL_DEFINE1(brk
, unsigned long, brk
)
195 unsigned long retval
;
196 unsigned long newbrk
, oldbrk
, origbrk
;
197 struct mm_struct
*mm
= current
->mm
;
198 struct vm_area_struct
*next
;
199 unsigned long min_brk
;
201 bool downgraded
= false;
204 brk
= untagged_addr(brk
);
206 if (down_write_killable(&mm
->mmap_sem
))
211 #ifdef CONFIG_COMPAT_BRK
213 * CONFIG_COMPAT_BRK can still be overridden by setting
214 * randomize_va_space to 2, which will still cause mm->start_brk
215 * to be arbitrarily shifted
217 if (current
->brk_randomized
)
218 min_brk
= mm
->start_brk
;
220 min_brk
= mm
->end_data
;
222 min_brk
= mm
->start_brk
;
228 * Check against rlimit here. If this check is done later after the test
229 * of oldbrk with newbrk then it can escape the test and let the data
230 * segment grow beyond its set limit the in case where the limit is
231 * not page aligned -Ram Gupta
233 if (check_data_rlimit(rlimit(RLIMIT_DATA
), brk
, mm
->start_brk
,
234 mm
->end_data
, mm
->start_data
))
237 newbrk
= PAGE_ALIGN(brk
);
238 oldbrk
= PAGE_ALIGN(mm
->brk
);
239 if (oldbrk
== newbrk
) {
245 * Always allow shrinking brk.
246 * __do_munmap() may downgrade mmap_sem to read.
248 if (brk
<= mm
->brk
) {
252 * mm->brk must to be protected by write mmap_sem so update it
253 * before downgrading mmap_sem. When __do_munmap() fails,
254 * mm->brk will be restored from origbrk.
257 ret
= __do_munmap(mm
, newbrk
, oldbrk
-newbrk
, &uf
, true);
261 } else if (ret
== 1) {
267 /* Check against existing mmap mappings. */
268 next
= find_vma(mm
, oldbrk
);
269 if (next
&& newbrk
+ PAGE_SIZE
> vm_start_gap(next
))
272 /* Ok, looks good - let it rip. */
273 if (do_brk_flags(oldbrk
, newbrk
-oldbrk
, 0, &uf
) < 0)
278 populate
= newbrk
> oldbrk
&& (mm
->def_flags
& VM_LOCKED
) != 0;
280 up_read(&mm
->mmap_sem
);
282 up_write(&mm
->mmap_sem
);
283 userfaultfd_unmap_complete(mm
, &uf
);
285 mm_populate(oldbrk
, newbrk
- oldbrk
);
290 up_write(&mm
->mmap_sem
);
294 static inline unsigned long vma_compute_gap(struct vm_area_struct
*vma
)
296 unsigned long gap
, prev_end
;
299 * Note: in the rare case of a VM_GROWSDOWN above a VM_GROWSUP, we
300 * allow two stack_guard_gaps between them here, and when choosing
301 * an unmapped area; whereas when expanding we only require one.
302 * That's a little inconsistent, but keeps the code here simpler.
304 gap
= vm_start_gap(vma
);
306 prev_end
= vm_end_gap(vma
->vm_prev
);
315 #ifdef CONFIG_DEBUG_VM_RB
316 static unsigned long vma_compute_subtree_gap(struct vm_area_struct
*vma
)
318 unsigned long max
= vma_compute_gap(vma
), subtree_gap
;
319 if (vma
->vm_rb
.rb_left
) {
320 subtree_gap
= rb_entry(vma
->vm_rb
.rb_left
,
321 struct vm_area_struct
, vm_rb
)->rb_subtree_gap
;
322 if (subtree_gap
> max
)
325 if (vma
->vm_rb
.rb_right
) {
326 subtree_gap
= rb_entry(vma
->vm_rb
.rb_right
,
327 struct vm_area_struct
, vm_rb
)->rb_subtree_gap
;
328 if (subtree_gap
> max
)
334 static int browse_rb(struct mm_struct
*mm
)
336 struct rb_root
*root
= &mm
->mm_rb
;
337 int i
= 0, j
, bug
= 0;
338 struct rb_node
*nd
, *pn
= NULL
;
339 unsigned long prev
= 0, pend
= 0;
341 for (nd
= rb_first(root
); nd
; nd
= rb_next(nd
)) {
342 struct vm_area_struct
*vma
;
343 vma
= rb_entry(nd
, struct vm_area_struct
, vm_rb
);
344 if (vma
->vm_start
< prev
) {
345 pr_emerg("vm_start %lx < prev %lx\n",
346 vma
->vm_start
, prev
);
349 if (vma
->vm_start
< pend
) {
350 pr_emerg("vm_start %lx < pend %lx\n",
351 vma
->vm_start
, pend
);
354 if (vma
->vm_start
> vma
->vm_end
) {
355 pr_emerg("vm_start %lx > vm_end %lx\n",
356 vma
->vm_start
, vma
->vm_end
);
359 spin_lock(&mm
->page_table_lock
);
360 if (vma
->rb_subtree_gap
!= vma_compute_subtree_gap(vma
)) {
361 pr_emerg("free gap %lx, correct %lx\n",
363 vma_compute_subtree_gap(vma
));
366 spin_unlock(&mm
->page_table_lock
);
369 prev
= vma
->vm_start
;
373 for (nd
= pn
; nd
; nd
= rb_prev(nd
))
376 pr_emerg("backwards %d, forwards %d\n", j
, i
);
382 static void validate_mm_rb(struct rb_root
*root
, struct vm_area_struct
*ignore
)
386 for (nd
= rb_first(root
); nd
; nd
= rb_next(nd
)) {
387 struct vm_area_struct
*vma
;
388 vma
= rb_entry(nd
, struct vm_area_struct
, vm_rb
);
389 VM_BUG_ON_VMA(vma
!= ignore
&&
390 vma
->rb_subtree_gap
!= vma_compute_subtree_gap(vma
),
395 static void validate_mm(struct mm_struct
*mm
)
399 unsigned long highest_address
= 0;
400 struct vm_area_struct
*vma
= mm
->mmap
;
403 struct anon_vma
*anon_vma
= vma
->anon_vma
;
404 struct anon_vma_chain
*avc
;
407 anon_vma_lock_read(anon_vma
);
408 list_for_each_entry(avc
, &vma
->anon_vma_chain
, same_vma
)
409 anon_vma_interval_tree_verify(avc
);
410 anon_vma_unlock_read(anon_vma
);
413 highest_address
= vm_end_gap(vma
);
417 if (i
!= mm
->map_count
) {
418 pr_emerg("map_count %d vm_next %d\n", mm
->map_count
, i
);
421 if (highest_address
!= mm
->highest_vm_end
) {
422 pr_emerg("mm->highest_vm_end %lx, found %lx\n",
423 mm
->highest_vm_end
, highest_address
);
427 if (i
!= mm
->map_count
) {
429 pr_emerg("map_count %d rb %d\n", mm
->map_count
, i
);
432 VM_BUG_ON_MM(bug
, mm
);
435 #define validate_mm_rb(root, ignore) do { } while (0)
436 #define validate_mm(mm) do { } while (0)
439 RB_DECLARE_CALLBACKS_MAX(static, vma_gap_callbacks
,
440 struct vm_area_struct
, vm_rb
,
441 unsigned long, rb_subtree_gap
, vma_compute_gap
)
444 * Update augmented rbtree rb_subtree_gap values after vma->vm_start or
445 * vma->vm_prev->vm_end values changed, without modifying the vma's position
448 static void vma_gap_update(struct vm_area_struct
*vma
)
451 * As it turns out, RB_DECLARE_CALLBACKS_MAX() already created
452 * a callback function that does exactly what we want.
454 vma_gap_callbacks_propagate(&vma
->vm_rb
, NULL
);
457 static inline void vma_rb_insert(struct vm_area_struct
*vma
,
458 struct rb_root
*root
)
460 /* All rb_subtree_gap values must be consistent prior to insertion */
461 validate_mm_rb(root
, NULL
);
463 rb_insert_augmented(&vma
->vm_rb
, root
, &vma_gap_callbacks
);
466 static void __vma_rb_erase(struct vm_area_struct
*vma
, struct rb_root
*root
)
469 * Note rb_erase_augmented is a fairly large inline function,
470 * so make sure we instantiate it only once with our desired
471 * augmented rbtree callbacks.
473 rb_erase_augmented(&vma
->vm_rb
, root
, &vma_gap_callbacks
);
476 static __always_inline
void vma_rb_erase_ignore(struct vm_area_struct
*vma
,
477 struct rb_root
*root
,
478 struct vm_area_struct
*ignore
)
481 * All rb_subtree_gap values must be consistent prior to erase,
482 * with the possible exception of the "next" vma being erased if
483 * next->vm_start was reduced.
485 validate_mm_rb(root
, ignore
);
487 __vma_rb_erase(vma
, root
);
490 static __always_inline
void vma_rb_erase(struct vm_area_struct
*vma
,
491 struct rb_root
*root
)
494 * All rb_subtree_gap values must be consistent prior to erase,
495 * with the possible exception of the vma being erased.
497 validate_mm_rb(root
, vma
);
499 __vma_rb_erase(vma
, root
);
503 * vma has some anon_vma assigned, and is already inserted on that
504 * anon_vma's interval trees.
506 * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the
507 * vma must be removed from the anon_vma's interval trees using
508 * anon_vma_interval_tree_pre_update_vma().
510 * After the update, the vma will be reinserted using
511 * anon_vma_interval_tree_post_update_vma().
513 * The entire update must be protected by exclusive mmap_sem and by
514 * the root anon_vma's mutex.
517 anon_vma_interval_tree_pre_update_vma(struct vm_area_struct
*vma
)
519 struct anon_vma_chain
*avc
;
521 list_for_each_entry(avc
, &vma
->anon_vma_chain
, same_vma
)
522 anon_vma_interval_tree_remove(avc
, &avc
->anon_vma
->rb_root
);
526 anon_vma_interval_tree_post_update_vma(struct vm_area_struct
*vma
)
528 struct anon_vma_chain
*avc
;
530 list_for_each_entry(avc
, &vma
->anon_vma_chain
, same_vma
)
531 anon_vma_interval_tree_insert(avc
, &avc
->anon_vma
->rb_root
);
534 static int find_vma_links(struct mm_struct
*mm
, unsigned long addr
,
535 unsigned long end
, struct vm_area_struct
**pprev
,
536 struct rb_node
***rb_link
, struct rb_node
**rb_parent
)
538 struct rb_node
**__rb_link
, *__rb_parent
, *rb_prev
;
540 __rb_link
= &mm
->mm_rb
.rb_node
;
541 rb_prev
= __rb_parent
= NULL
;
544 struct vm_area_struct
*vma_tmp
;
546 __rb_parent
= *__rb_link
;
547 vma_tmp
= rb_entry(__rb_parent
, struct vm_area_struct
, vm_rb
);
549 if (vma_tmp
->vm_end
> addr
) {
550 /* Fail if an existing vma overlaps the area */
551 if (vma_tmp
->vm_start
< end
)
553 __rb_link
= &__rb_parent
->rb_left
;
555 rb_prev
= __rb_parent
;
556 __rb_link
= &__rb_parent
->rb_right
;
562 *pprev
= rb_entry(rb_prev
, struct vm_area_struct
, vm_rb
);
563 *rb_link
= __rb_link
;
564 *rb_parent
= __rb_parent
;
568 static unsigned long count_vma_pages_range(struct mm_struct
*mm
,
569 unsigned long addr
, unsigned long end
)
571 unsigned long nr_pages
= 0;
572 struct vm_area_struct
*vma
;
574 /* Find first overlaping mapping */
575 vma
= find_vma_intersection(mm
, addr
, end
);
579 nr_pages
= (min(end
, vma
->vm_end
) -
580 max(addr
, vma
->vm_start
)) >> PAGE_SHIFT
;
582 /* Iterate over the rest of the overlaps */
583 for (vma
= vma
->vm_next
; vma
; vma
= vma
->vm_next
) {
584 unsigned long overlap_len
;
586 if (vma
->vm_start
> end
)
589 overlap_len
= min(end
, vma
->vm_end
) - vma
->vm_start
;
590 nr_pages
+= overlap_len
>> PAGE_SHIFT
;
596 void __vma_link_rb(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
597 struct rb_node
**rb_link
, struct rb_node
*rb_parent
)
599 /* Update tracking information for the gap following the new vma. */
601 vma_gap_update(vma
->vm_next
);
603 mm
->highest_vm_end
= vm_end_gap(vma
);
606 * vma->vm_prev wasn't known when we followed the rbtree to find the
607 * correct insertion point for that vma. As a result, we could not
608 * update the vma vm_rb parents rb_subtree_gap values on the way down.
609 * So, we first insert the vma with a zero rb_subtree_gap value
610 * (to be consistent with what we did on the way down), and then
611 * immediately update the gap to the correct value. Finally we
612 * rebalance the rbtree after all augmented values have been set.
614 rb_link_node(&vma
->vm_rb
, rb_parent
, rb_link
);
615 vma
->rb_subtree_gap
= 0;
617 vma_rb_insert(vma
, &mm
->mm_rb
);
620 static void __vma_link_file(struct vm_area_struct
*vma
)
626 struct address_space
*mapping
= file
->f_mapping
;
628 if (vma
->vm_flags
& VM_DENYWRITE
)
629 atomic_dec(&file_inode(file
)->i_writecount
);
630 if (vma
->vm_flags
& VM_SHARED
)
631 atomic_inc(&mapping
->i_mmap_writable
);
633 flush_dcache_mmap_lock(mapping
);
634 vma_interval_tree_insert(vma
, &mapping
->i_mmap
);
635 flush_dcache_mmap_unlock(mapping
);
640 __vma_link(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
641 struct vm_area_struct
*prev
, struct rb_node
**rb_link
,
642 struct rb_node
*rb_parent
)
644 __vma_link_list(mm
, vma
, prev
, rb_parent
);
645 __vma_link_rb(mm
, vma
, rb_link
, rb_parent
);
648 static void vma_link(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
649 struct vm_area_struct
*prev
, struct rb_node
**rb_link
,
650 struct rb_node
*rb_parent
)
652 struct address_space
*mapping
= NULL
;
655 mapping
= vma
->vm_file
->f_mapping
;
656 i_mmap_lock_write(mapping
);
659 __vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
660 __vma_link_file(vma
);
663 i_mmap_unlock_write(mapping
);
670 * Helper for vma_adjust() in the split_vma insert case: insert a vma into the
671 * mm's list and rbtree. It has already been inserted into the interval tree.
673 static void __insert_vm_struct(struct mm_struct
*mm
, struct vm_area_struct
*vma
)
675 struct vm_area_struct
*prev
;
676 struct rb_node
**rb_link
, *rb_parent
;
678 if (find_vma_links(mm
, vma
->vm_start
, vma
->vm_end
,
679 &prev
, &rb_link
, &rb_parent
))
681 __vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
685 static __always_inline
void __vma_unlink_common(struct mm_struct
*mm
,
686 struct vm_area_struct
*vma
,
687 struct vm_area_struct
*prev
,
689 struct vm_area_struct
*ignore
)
691 struct vm_area_struct
*next
;
693 vma_rb_erase_ignore(vma
, &mm
->mm_rb
, ignore
);
696 prev
->vm_next
= next
;
700 prev
->vm_next
= next
;
705 next
->vm_prev
= prev
;
708 vmacache_invalidate(mm
);
711 static inline void __vma_unlink_prev(struct mm_struct
*mm
,
712 struct vm_area_struct
*vma
,
713 struct vm_area_struct
*prev
)
715 __vma_unlink_common(mm
, vma
, prev
, true, vma
);
719 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
720 * is already present in an i_mmap tree without adjusting the tree.
721 * The following helper function should be used when such adjustments
722 * are necessary. The "insert" vma (if any) is to be inserted
723 * before we drop the necessary locks.
725 int __vma_adjust(struct vm_area_struct
*vma
, unsigned long start
,
726 unsigned long end
, pgoff_t pgoff
, struct vm_area_struct
*insert
,
727 struct vm_area_struct
*expand
)
729 struct mm_struct
*mm
= vma
->vm_mm
;
730 struct vm_area_struct
*next
= vma
->vm_next
, *orig_vma
= vma
;
731 struct address_space
*mapping
= NULL
;
732 struct rb_root_cached
*root
= NULL
;
733 struct anon_vma
*anon_vma
= NULL
;
734 struct file
*file
= vma
->vm_file
;
735 bool start_changed
= false, end_changed
= false;
736 long adjust_next
= 0;
739 if (next
&& !insert
) {
740 struct vm_area_struct
*exporter
= NULL
, *importer
= NULL
;
742 if (end
>= next
->vm_end
) {
744 * vma expands, overlapping all the next, and
745 * perhaps the one after too (mprotect case 6).
746 * The only other cases that gets here are
747 * case 1, case 7 and case 8.
749 if (next
== expand
) {
751 * The only case where we don't expand "vma"
752 * and we expand "next" instead is case 8.
754 VM_WARN_ON(end
!= next
->vm_end
);
756 * remove_next == 3 means we're
757 * removing "vma" and that to do so we
758 * swapped "vma" and "next".
761 VM_WARN_ON(file
!= next
->vm_file
);
764 VM_WARN_ON(expand
!= vma
);
766 * case 1, 6, 7, remove_next == 2 is case 6,
767 * remove_next == 1 is case 1 or 7.
769 remove_next
= 1 + (end
> next
->vm_end
);
770 VM_WARN_ON(remove_next
== 2 &&
771 end
!= next
->vm_next
->vm_end
);
772 VM_WARN_ON(remove_next
== 1 &&
773 end
!= next
->vm_end
);
774 /* trim end to next, for case 6 first pass */
782 * If next doesn't have anon_vma, import from vma after
783 * next, if the vma overlaps with it.
785 if (remove_next
== 2 && !next
->anon_vma
)
786 exporter
= next
->vm_next
;
788 } else if (end
> next
->vm_start
) {
790 * vma expands, overlapping part of the next:
791 * mprotect case 5 shifting the boundary up.
793 adjust_next
= (end
- next
->vm_start
) >> PAGE_SHIFT
;
796 VM_WARN_ON(expand
!= importer
);
797 } else if (end
< vma
->vm_end
) {
799 * vma shrinks, and !insert tells it's not
800 * split_vma inserting another: so it must be
801 * mprotect case 4 shifting the boundary down.
803 adjust_next
= -((vma
->vm_end
- end
) >> PAGE_SHIFT
);
806 VM_WARN_ON(expand
!= importer
);
810 * Easily overlooked: when mprotect shifts the boundary,
811 * make sure the expanding vma has anon_vma set if the
812 * shrinking vma had, to cover any anon pages imported.
814 if (exporter
&& exporter
->anon_vma
&& !importer
->anon_vma
) {
817 importer
->anon_vma
= exporter
->anon_vma
;
818 error
= anon_vma_clone(importer
, exporter
);
824 vma_adjust_trans_huge(orig_vma
, start
, end
, adjust_next
);
827 mapping
= file
->f_mapping
;
828 root
= &mapping
->i_mmap
;
829 uprobe_munmap(vma
, vma
->vm_start
, vma
->vm_end
);
832 uprobe_munmap(next
, next
->vm_start
, next
->vm_end
);
834 i_mmap_lock_write(mapping
);
837 * Put into interval tree now, so instantiated pages
838 * are visible to arm/parisc __flush_dcache_page
839 * throughout; but we cannot insert into address
840 * space until vma start or end is updated.
842 __vma_link_file(insert
);
846 anon_vma
= vma
->anon_vma
;
847 if (!anon_vma
&& adjust_next
)
848 anon_vma
= next
->anon_vma
;
850 VM_WARN_ON(adjust_next
&& next
->anon_vma
&&
851 anon_vma
!= next
->anon_vma
);
852 anon_vma_lock_write(anon_vma
);
853 anon_vma_interval_tree_pre_update_vma(vma
);
855 anon_vma_interval_tree_pre_update_vma(next
);
859 flush_dcache_mmap_lock(mapping
);
860 vma_interval_tree_remove(vma
, root
);
862 vma_interval_tree_remove(next
, root
);
865 if (start
!= vma
->vm_start
) {
866 vma
->vm_start
= start
;
867 start_changed
= true;
869 if (end
!= vma
->vm_end
) {
873 vma
->vm_pgoff
= pgoff
;
875 next
->vm_start
+= adjust_next
<< PAGE_SHIFT
;
876 next
->vm_pgoff
+= adjust_next
;
881 vma_interval_tree_insert(next
, root
);
882 vma_interval_tree_insert(vma
, root
);
883 flush_dcache_mmap_unlock(mapping
);
888 * vma_merge has merged next into vma, and needs
889 * us to remove next before dropping the locks.
891 if (remove_next
!= 3)
892 __vma_unlink_prev(mm
, next
, vma
);
895 * vma is not before next if they've been
898 * pre-swap() next->vm_start was reduced so
899 * tell validate_mm_rb to ignore pre-swap()
900 * "next" (which is stored in post-swap()
903 __vma_unlink_common(mm
, next
, NULL
, false, vma
);
905 __remove_shared_vm_struct(next
, file
, mapping
);
908 * split_vma has split insert from vma, and needs
909 * us to insert it before dropping the locks
910 * (it may either follow vma or precede it).
912 __insert_vm_struct(mm
, insert
);
918 mm
->highest_vm_end
= vm_end_gap(vma
);
919 else if (!adjust_next
)
920 vma_gap_update(next
);
925 anon_vma_interval_tree_post_update_vma(vma
);
927 anon_vma_interval_tree_post_update_vma(next
);
928 anon_vma_unlock_write(anon_vma
);
931 i_mmap_unlock_write(mapping
);
942 uprobe_munmap(next
, next
->vm_start
, next
->vm_end
);
946 anon_vma_merge(vma
, next
);
948 mpol_put(vma_policy(next
));
951 * In mprotect's case 6 (see comments on vma_merge),
952 * we must remove another next too. It would clutter
953 * up the code too much to do both in one go.
955 if (remove_next
!= 3) {
957 * If "next" was removed and vma->vm_end was
958 * expanded (up) over it, in turn
959 * "next->vm_prev->vm_end" changed and the
960 * "vma->vm_next" gap must be updated.
965 * For the scope of the comment "next" and
966 * "vma" considered pre-swap(): if "vma" was
967 * removed, next->vm_start was expanded (down)
968 * over it and the "next" gap must be updated.
969 * Because of the swap() the post-swap() "vma"
970 * actually points to pre-swap() "next"
971 * (post-swap() "next" as opposed is now a
976 if (remove_next
== 2) {
982 vma_gap_update(next
);
985 * If remove_next == 2 we obviously can't
988 * If remove_next == 3 we can't reach this
989 * path because pre-swap() next is always not
990 * NULL. pre-swap() "next" is not being
991 * removed and its next->vm_end is not altered
992 * (and furthermore "end" already matches
993 * next->vm_end in remove_next == 3).
995 * We reach this only in the remove_next == 1
996 * case if the "next" vma that was removed was
997 * the highest vma of the mm. However in such
998 * case next->vm_end == "end" and the extended
999 * "vma" has vma->vm_end == next->vm_end so
1000 * mm->highest_vm_end doesn't need any update
1001 * in remove_next == 1 case.
1003 VM_WARN_ON(mm
->highest_vm_end
!= vm_end_gap(vma
));
1007 uprobe_mmap(insert
);
1015 * If the vma has a ->close operation then the driver probably needs to release
1016 * per-vma resources, so we don't attempt to merge those.
1018 static inline int is_mergeable_vma(struct vm_area_struct
*vma
,
1019 struct file
*file
, unsigned long vm_flags
,
1020 struct vm_userfaultfd_ctx vm_userfaultfd_ctx
)
1023 * VM_SOFTDIRTY should not prevent from VMA merging, if we
1024 * match the flags but dirty bit -- the caller should mark
1025 * merged VMA as dirty. If dirty bit won't be excluded from
1026 * comparison, we increase pressure on the memory system forcing
1027 * the kernel to generate new VMAs when old one could be
1030 if ((vma
->vm_flags
^ vm_flags
) & ~VM_SOFTDIRTY
)
1032 if (vma
->vm_file
!= file
)
1034 if (vma
->vm_ops
&& vma
->vm_ops
->close
)
1036 if (!is_mergeable_vm_userfaultfd_ctx(vma
, vm_userfaultfd_ctx
))
1041 static inline int is_mergeable_anon_vma(struct anon_vma
*anon_vma1
,
1042 struct anon_vma
*anon_vma2
,
1043 struct vm_area_struct
*vma
)
1046 * The list_is_singular() test is to avoid merging VMA cloned from
1047 * parents. This can improve scalability caused by anon_vma lock.
1049 if ((!anon_vma1
|| !anon_vma2
) && (!vma
||
1050 list_is_singular(&vma
->anon_vma_chain
)))
1052 return anon_vma1
== anon_vma2
;
1056 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
1057 * in front of (at a lower virtual address and file offset than) the vma.
1059 * We cannot merge two vmas if they have differently assigned (non-NULL)
1060 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
1062 * We don't check here for the merged mmap wrapping around the end of pagecache
1063 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
1064 * wrap, nor mmaps which cover the final page at index -1UL.
1067 can_vma_merge_before(struct vm_area_struct
*vma
, unsigned long vm_flags
,
1068 struct anon_vma
*anon_vma
, struct file
*file
,
1070 struct vm_userfaultfd_ctx vm_userfaultfd_ctx
)
1072 if (is_mergeable_vma(vma
, file
, vm_flags
, vm_userfaultfd_ctx
) &&
1073 is_mergeable_anon_vma(anon_vma
, vma
->anon_vma
, vma
)) {
1074 if (vma
->vm_pgoff
== vm_pgoff
)
1081 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
1082 * beyond (at a higher virtual address and file offset than) the vma.
1084 * We cannot merge two vmas if they have differently assigned (non-NULL)
1085 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
1088 can_vma_merge_after(struct vm_area_struct
*vma
, unsigned long vm_flags
,
1089 struct anon_vma
*anon_vma
, struct file
*file
,
1091 struct vm_userfaultfd_ctx vm_userfaultfd_ctx
)
1093 if (is_mergeable_vma(vma
, file
, vm_flags
, vm_userfaultfd_ctx
) &&
1094 is_mergeable_anon_vma(anon_vma
, vma
->anon_vma
, vma
)) {
1096 vm_pglen
= vma_pages(vma
);
1097 if (vma
->vm_pgoff
+ vm_pglen
== vm_pgoff
)
1104 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
1105 * whether that can be merged with its predecessor or its successor.
1106 * Or both (it neatly fills a hole).
1108 * In most cases - when called for mmap, brk or mremap - [addr,end) is
1109 * certain not to be mapped by the time vma_merge is called; but when
1110 * called for mprotect, it is certain to be already mapped (either at
1111 * an offset within prev, or at the start of next), and the flags of
1112 * this area are about to be changed to vm_flags - and the no-change
1113 * case has already been eliminated.
1115 * The following mprotect cases have to be considered, where AAAA is
1116 * the area passed down from mprotect_fixup, never extending beyond one
1117 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
1119 * AAAA AAAA AAAA AAAA
1120 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
1121 * cannot merge might become might become might become
1122 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
1123 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
1124 * mremap move: PPPPXXXXXXXX 8
1126 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
1127 * might become case 1 below case 2 below case 3 below
1129 * It is important for case 8 that the vma NNNN overlapping the
1130 * region AAAA is never going to extended over XXXX. Instead XXXX must
1131 * be extended in region AAAA and NNNN must be removed. This way in
1132 * all cases where vma_merge succeeds, the moment vma_adjust drops the
1133 * rmap_locks, the properties of the merged vma will be already
1134 * correct for the whole merged range. Some of those properties like
1135 * vm_page_prot/vm_flags may be accessed by rmap_walks and they must
1136 * be correct for the whole merged range immediately after the
1137 * rmap_locks are released. Otherwise if XXXX would be removed and
1138 * NNNN would be extended over the XXXX range, remove_migration_ptes
1139 * or other rmap walkers (if working on addresses beyond the "end"
1140 * parameter) may establish ptes with the wrong permissions of NNNN
1141 * instead of the right permissions of XXXX.
1143 struct vm_area_struct
*vma_merge(struct mm_struct
*mm
,
1144 struct vm_area_struct
*prev
, unsigned long addr
,
1145 unsigned long end
, unsigned long vm_flags
,
1146 struct anon_vma
*anon_vma
, struct file
*file
,
1147 pgoff_t pgoff
, struct mempolicy
*policy
,
1148 struct vm_userfaultfd_ctx vm_userfaultfd_ctx
)
1150 pgoff_t pglen
= (end
- addr
) >> PAGE_SHIFT
;
1151 struct vm_area_struct
*area
, *next
;
1155 * We later require that vma->vm_flags == vm_flags,
1156 * so this tests vma->vm_flags & VM_SPECIAL, too.
1158 if (vm_flags
& VM_SPECIAL
)
1162 next
= prev
->vm_next
;
1166 if (area
&& area
->vm_end
== end
) /* cases 6, 7, 8 */
1167 next
= next
->vm_next
;
1169 /* verify some invariant that must be enforced by the caller */
1170 VM_WARN_ON(prev
&& addr
<= prev
->vm_start
);
1171 VM_WARN_ON(area
&& end
> area
->vm_end
);
1172 VM_WARN_ON(addr
>= end
);
1175 * Can it merge with the predecessor?
1177 if (prev
&& prev
->vm_end
== addr
&&
1178 mpol_equal(vma_policy(prev
), policy
) &&
1179 can_vma_merge_after(prev
, vm_flags
,
1180 anon_vma
, file
, pgoff
,
1181 vm_userfaultfd_ctx
)) {
1183 * OK, it can. Can we now merge in the successor as well?
1185 if (next
&& end
== next
->vm_start
&&
1186 mpol_equal(policy
, vma_policy(next
)) &&
1187 can_vma_merge_before(next
, vm_flags
,
1190 vm_userfaultfd_ctx
) &&
1191 is_mergeable_anon_vma(prev
->anon_vma
,
1192 next
->anon_vma
, NULL
)) {
1194 err
= __vma_adjust(prev
, prev
->vm_start
,
1195 next
->vm_end
, prev
->vm_pgoff
, NULL
,
1197 } else /* cases 2, 5, 7 */
1198 err
= __vma_adjust(prev
, prev
->vm_start
,
1199 end
, prev
->vm_pgoff
, NULL
, prev
);
1202 khugepaged_enter_vma_merge(prev
, vm_flags
);
1207 * Can this new request be merged in front of next?
1209 if (next
&& end
== next
->vm_start
&&
1210 mpol_equal(policy
, vma_policy(next
)) &&
1211 can_vma_merge_before(next
, vm_flags
,
1212 anon_vma
, file
, pgoff
+pglen
,
1213 vm_userfaultfd_ctx
)) {
1214 if (prev
&& addr
< prev
->vm_end
) /* case 4 */
1215 err
= __vma_adjust(prev
, prev
->vm_start
,
1216 addr
, prev
->vm_pgoff
, NULL
, next
);
1217 else { /* cases 3, 8 */
1218 err
= __vma_adjust(area
, addr
, next
->vm_end
,
1219 next
->vm_pgoff
- pglen
, NULL
, next
);
1221 * In case 3 area is already equal to next and
1222 * this is a noop, but in case 8 "area" has
1223 * been removed and next was expanded over it.
1229 khugepaged_enter_vma_merge(area
, vm_flags
);
1237 * Rough compatbility check to quickly see if it's even worth looking
1238 * at sharing an anon_vma.
1240 * They need to have the same vm_file, and the flags can only differ
1241 * in things that mprotect may change.
1243 * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that
1244 * we can merge the two vma's. For example, we refuse to merge a vma if
1245 * there is a vm_ops->close() function, because that indicates that the
1246 * driver is doing some kind of reference counting. But that doesn't
1247 * really matter for the anon_vma sharing case.
1249 static int anon_vma_compatible(struct vm_area_struct
*a
, struct vm_area_struct
*b
)
1251 return a
->vm_end
== b
->vm_start
&&
1252 mpol_equal(vma_policy(a
), vma_policy(b
)) &&
1253 a
->vm_file
== b
->vm_file
&&
1254 !((a
->vm_flags
^ b
->vm_flags
) & ~(VM_READ
|VM_WRITE
|VM_EXEC
|VM_SOFTDIRTY
)) &&
1255 b
->vm_pgoff
== a
->vm_pgoff
+ ((b
->vm_start
- a
->vm_start
) >> PAGE_SHIFT
);
1259 * Do some basic sanity checking to see if we can re-use the anon_vma
1260 * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be
1261 * the same as 'old', the other will be the new one that is trying
1262 * to share the anon_vma.
1264 * NOTE! This runs with mm_sem held for reading, so it is possible that
1265 * the anon_vma of 'old' is concurrently in the process of being set up
1266 * by another page fault trying to merge _that_. But that's ok: if it
1267 * is being set up, that automatically means that it will be a singleton
1268 * acceptable for merging, so we can do all of this optimistically. But
1269 * we do that READ_ONCE() to make sure that we never re-load the pointer.
1271 * IOW: that the "list_is_singular()" test on the anon_vma_chain only
1272 * matters for the 'stable anon_vma' case (ie the thing we want to avoid
1273 * is to return an anon_vma that is "complex" due to having gone through
1276 * We also make sure that the two vma's are compatible (adjacent,
1277 * and with the same memory policies). That's all stable, even with just
1278 * a read lock on the mm_sem.
1280 static struct anon_vma
*reusable_anon_vma(struct vm_area_struct
*old
, struct vm_area_struct
*a
, struct vm_area_struct
*b
)
1282 if (anon_vma_compatible(a
, b
)) {
1283 struct anon_vma
*anon_vma
= READ_ONCE(old
->anon_vma
);
1285 if (anon_vma
&& list_is_singular(&old
->anon_vma_chain
))
1292 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
1293 * neighbouring vmas for a suitable anon_vma, before it goes off
1294 * to allocate a new anon_vma. It checks because a repetitive
1295 * sequence of mprotects and faults may otherwise lead to distinct
1296 * anon_vmas being allocated, preventing vma merge in subsequent
1299 struct anon_vma
*find_mergeable_anon_vma(struct vm_area_struct
*vma
)
1301 struct anon_vma
*anon_vma
;
1302 struct vm_area_struct
*near
;
1304 near
= vma
->vm_next
;
1308 anon_vma
= reusable_anon_vma(near
, vma
, near
);
1312 near
= vma
->vm_prev
;
1316 anon_vma
= reusable_anon_vma(near
, near
, vma
);
1321 * There's no absolute need to look only at touching neighbours:
1322 * we could search further afield for "compatible" anon_vmas.
1323 * But it would probably just be a waste of time searching,
1324 * or lead to too many vmas hanging off the same anon_vma.
1325 * We're trying to allow mprotect remerging later on,
1326 * not trying to minimize memory used for anon_vmas.
1332 * If a hint addr is less than mmap_min_addr change hint to be as
1333 * low as possible but still greater than mmap_min_addr
1335 static inline unsigned long round_hint_to_min(unsigned long hint
)
1338 if (((void *)hint
!= NULL
) &&
1339 (hint
< mmap_min_addr
))
1340 return PAGE_ALIGN(mmap_min_addr
);
1344 static inline int mlock_future_check(struct mm_struct
*mm
,
1345 unsigned long flags
,
1348 unsigned long locked
, lock_limit
;
1350 /* mlock MCL_FUTURE? */
1351 if (flags
& VM_LOCKED
) {
1352 locked
= len
>> PAGE_SHIFT
;
1353 locked
+= mm
->locked_vm
;
1354 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
1355 lock_limit
>>= PAGE_SHIFT
;
1356 if (locked
> lock_limit
&& !capable(CAP_IPC_LOCK
))
1362 static inline u64
file_mmap_size_max(struct file
*file
, struct inode
*inode
)
1364 if (S_ISREG(inode
->i_mode
))
1365 return MAX_LFS_FILESIZE
;
1367 if (S_ISBLK(inode
->i_mode
))
1368 return MAX_LFS_FILESIZE
;
1370 if (S_ISSOCK(inode
->i_mode
))
1371 return MAX_LFS_FILESIZE
;
1373 /* Special "we do even unsigned file positions" case */
1374 if (file
->f_mode
& FMODE_UNSIGNED_OFFSET
)
1377 /* Yes, random drivers might want more. But I'm tired of buggy drivers */
1381 static inline bool file_mmap_ok(struct file
*file
, struct inode
*inode
,
1382 unsigned long pgoff
, unsigned long len
)
1384 u64 maxsize
= file_mmap_size_max(file
, inode
);
1386 if (maxsize
&& len
> maxsize
)
1389 if (pgoff
> maxsize
>> PAGE_SHIFT
)
1395 * The caller must hold down_write(¤t->mm->mmap_sem).
1397 unsigned long do_mmap(struct file
*file
, unsigned long addr
,
1398 unsigned long len
, unsigned long prot
,
1399 unsigned long flags
, vm_flags_t vm_flags
,
1400 unsigned long pgoff
, unsigned long *populate
,
1401 struct list_head
*uf
)
1403 struct mm_struct
*mm
= current
->mm
;
1412 * Does the application expect PROT_READ to imply PROT_EXEC?
1414 * (the exception is when the underlying filesystem is noexec
1415 * mounted, in which case we dont add PROT_EXEC.)
1417 if ((prot
& PROT_READ
) && (current
->personality
& READ_IMPLIES_EXEC
))
1418 if (!(file
&& path_noexec(&file
->f_path
)))
1421 /* force arch specific MAP_FIXED handling in get_unmapped_area */
1422 if (flags
& MAP_FIXED_NOREPLACE
)
1425 if (!(flags
& MAP_FIXED
))
1426 addr
= round_hint_to_min(addr
);
1428 /* Careful about overflows.. */
1429 len
= PAGE_ALIGN(len
);
1433 /* offset overflow? */
1434 if ((pgoff
+ (len
>> PAGE_SHIFT
)) < pgoff
)
1437 /* Too many mappings? */
1438 if (mm
->map_count
> sysctl_max_map_count
)
1441 /* Obtain the address to map to. we verify (or select) it and ensure
1442 * that it represents a valid section of the address space.
1444 addr
= get_unmapped_area(file
, addr
, len
, pgoff
, flags
);
1445 if (offset_in_page(addr
))
1448 if (flags
& MAP_FIXED_NOREPLACE
) {
1449 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
1451 if (vma
&& vma
->vm_start
< addr
+ len
)
1455 if (prot
== PROT_EXEC
) {
1456 pkey
= execute_only_pkey(mm
);
1461 /* Do simple checking here so the lower-level routines won't have
1462 * to. we assume access permissions have been handled by the open
1463 * of the memory object, so we don't do any here.
1465 vm_flags
|= calc_vm_prot_bits(prot
, pkey
) | calc_vm_flag_bits(flags
) |
1466 mm
->def_flags
| VM_MAYREAD
| VM_MAYWRITE
| VM_MAYEXEC
;
1468 if (flags
& MAP_LOCKED
)
1469 if (!can_do_mlock())
1472 if (mlock_future_check(mm
, vm_flags
, len
))
1476 struct inode
*inode
= file_inode(file
);
1477 unsigned long flags_mask
;
1479 if (!file_mmap_ok(file
, inode
, pgoff
, len
))
1482 flags_mask
= LEGACY_MAP_MASK
| file
->f_op
->mmap_supported_flags
;
1484 switch (flags
& MAP_TYPE
) {
1487 * Force use of MAP_SHARED_VALIDATE with non-legacy
1488 * flags. E.g. MAP_SYNC is dangerous to use with
1489 * MAP_SHARED as you don't know which consistency model
1490 * you will get. We silently ignore unsupported flags
1491 * with MAP_SHARED to preserve backward compatibility.
1493 flags
&= LEGACY_MAP_MASK
;
1495 case MAP_SHARED_VALIDATE
:
1496 if (flags
& ~flags_mask
)
1498 if (prot
& PROT_WRITE
) {
1499 if (!(file
->f_mode
& FMODE_WRITE
))
1501 if (IS_SWAPFILE(file
->f_mapping
->host
))
1506 * Make sure we don't allow writing to an append-only
1509 if (IS_APPEND(inode
) && (file
->f_mode
& FMODE_WRITE
))
1513 * Make sure there are no mandatory locks on the file.
1515 if (locks_verify_locked(file
))
1518 vm_flags
|= VM_SHARED
| VM_MAYSHARE
;
1519 if (!(file
->f_mode
& FMODE_WRITE
))
1520 vm_flags
&= ~(VM_MAYWRITE
| VM_SHARED
);
1524 if (!(file
->f_mode
& FMODE_READ
))
1526 if (path_noexec(&file
->f_path
)) {
1527 if (vm_flags
& VM_EXEC
)
1529 vm_flags
&= ~VM_MAYEXEC
;
1532 if (!file
->f_op
->mmap
)
1534 if (vm_flags
& (VM_GROWSDOWN
|VM_GROWSUP
))
1542 switch (flags
& MAP_TYPE
) {
1544 if (vm_flags
& (VM_GROWSDOWN
|VM_GROWSUP
))
1550 vm_flags
|= VM_SHARED
| VM_MAYSHARE
;
1554 * Set pgoff according to addr for anon_vma.
1556 pgoff
= addr
>> PAGE_SHIFT
;
1564 * Set 'VM_NORESERVE' if we should not account for the
1565 * memory use of this mapping.
1567 if (flags
& MAP_NORESERVE
) {
1568 /* We honor MAP_NORESERVE if allowed to overcommit */
1569 if (sysctl_overcommit_memory
!= OVERCOMMIT_NEVER
)
1570 vm_flags
|= VM_NORESERVE
;
1572 /* hugetlb applies strict overcommit unless MAP_NORESERVE */
1573 if (file
&& is_file_hugepages(file
))
1574 vm_flags
|= VM_NORESERVE
;
1577 addr
= mmap_region(file
, addr
, len
, vm_flags
, pgoff
, uf
);
1578 if (!IS_ERR_VALUE(addr
) &&
1579 ((vm_flags
& VM_LOCKED
) ||
1580 (flags
& (MAP_POPULATE
| MAP_NONBLOCK
)) == MAP_POPULATE
))
1585 unsigned long ksys_mmap_pgoff(unsigned long addr
, unsigned long len
,
1586 unsigned long prot
, unsigned long flags
,
1587 unsigned long fd
, unsigned long pgoff
)
1589 struct file
*file
= NULL
;
1590 unsigned long retval
;
1592 addr
= untagged_addr(addr
);
1594 if (!(flags
& MAP_ANONYMOUS
)) {
1595 audit_mmap_fd(fd
, flags
);
1599 if (is_file_hugepages(file
))
1600 len
= ALIGN(len
, huge_page_size(hstate_file(file
)));
1602 if (unlikely(flags
& MAP_HUGETLB
&& !is_file_hugepages(file
)))
1604 } else if (flags
& MAP_HUGETLB
) {
1605 struct user_struct
*user
= NULL
;
1608 hs
= hstate_sizelog((flags
>> MAP_HUGE_SHIFT
) & MAP_HUGE_MASK
);
1612 len
= ALIGN(len
, huge_page_size(hs
));
1614 * VM_NORESERVE is used because the reservations will be
1615 * taken when vm_ops->mmap() is called
1616 * A dummy user value is used because we are not locking
1617 * memory so no accounting is necessary
1619 file
= hugetlb_file_setup(HUGETLB_ANON_FILE
, len
,
1621 &user
, HUGETLB_ANONHUGE_INODE
,
1622 (flags
>> MAP_HUGE_SHIFT
) & MAP_HUGE_MASK
);
1624 return PTR_ERR(file
);
1627 flags
&= ~(MAP_EXECUTABLE
| MAP_DENYWRITE
);
1629 retval
= vm_mmap_pgoff(file
, addr
, len
, prot
, flags
, pgoff
);
1636 SYSCALL_DEFINE6(mmap_pgoff
, unsigned long, addr
, unsigned long, len
,
1637 unsigned long, prot
, unsigned long, flags
,
1638 unsigned long, fd
, unsigned long, pgoff
)
1640 return ksys_mmap_pgoff(addr
, len
, prot
, flags
, fd
, pgoff
);
1643 #ifdef __ARCH_WANT_SYS_OLD_MMAP
1644 struct mmap_arg_struct
{
1648 unsigned long flags
;
1650 unsigned long offset
;
1653 SYSCALL_DEFINE1(old_mmap
, struct mmap_arg_struct __user
*, arg
)
1655 struct mmap_arg_struct a
;
1657 if (copy_from_user(&a
, arg
, sizeof(a
)))
1659 if (offset_in_page(a
.offset
))
1662 return ksys_mmap_pgoff(a
.addr
, a
.len
, a
.prot
, a
.flags
, a
.fd
,
1663 a
.offset
>> PAGE_SHIFT
);
1665 #endif /* __ARCH_WANT_SYS_OLD_MMAP */
1668 * Some shared mappings will want the pages marked read-only
1669 * to track write events. If so, we'll downgrade vm_page_prot
1670 * to the private version (using protection_map[] without the
1673 int vma_wants_writenotify(struct vm_area_struct
*vma
, pgprot_t vm_page_prot
)
1675 vm_flags_t vm_flags
= vma
->vm_flags
;
1676 const struct vm_operations_struct
*vm_ops
= vma
->vm_ops
;
1678 /* If it was private or non-writable, the write bit is already clear */
1679 if ((vm_flags
& (VM_WRITE
|VM_SHARED
)) != ((VM_WRITE
|VM_SHARED
)))
1682 /* The backer wishes to know when pages are first written to? */
1683 if (vm_ops
&& (vm_ops
->page_mkwrite
|| vm_ops
->pfn_mkwrite
))
1686 /* The open routine did something to the protections that pgprot_modify
1687 * won't preserve? */
1688 if (pgprot_val(vm_page_prot
) !=
1689 pgprot_val(vm_pgprot_modify(vm_page_prot
, vm_flags
)))
1692 /* Do we need to track softdirty? */
1693 if (IS_ENABLED(CONFIG_MEM_SOFT_DIRTY
) && !(vm_flags
& VM_SOFTDIRTY
))
1696 /* Specialty mapping? */
1697 if (vm_flags
& VM_PFNMAP
)
1700 /* Can the mapping track the dirty pages? */
1701 return vma
->vm_file
&& vma
->vm_file
->f_mapping
&&
1702 mapping_cap_account_dirty(vma
->vm_file
->f_mapping
);
1706 * We account for memory if it's a private writeable mapping,
1707 * not hugepages and VM_NORESERVE wasn't set.
1709 static inline int accountable_mapping(struct file
*file
, vm_flags_t vm_flags
)
1712 * hugetlb has its own accounting separate from the core VM
1713 * VM_HUGETLB may not be set yet so we cannot check for that flag.
1715 if (file
&& is_file_hugepages(file
))
1718 return (vm_flags
& (VM_NORESERVE
| VM_SHARED
| VM_WRITE
)) == VM_WRITE
;
1721 unsigned long mmap_region(struct file
*file
, unsigned long addr
,
1722 unsigned long len
, vm_flags_t vm_flags
, unsigned long pgoff
,
1723 struct list_head
*uf
)
1725 struct mm_struct
*mm
= current
->mm
;
1726 struct vm_area_struct
*vma
, *prev
;
1728 struct rb_node
**rb_link
, *rb_parent
;
1729 unsigned long charged
= 0;
1731 /* Check against address space limit. */
1732 if (!may_expand_vm(mm
, vm_flags
, len
>> PAGE_SHIFT
)) {
1733 unsigned long nr_pages
;
1736 * MAP_FIXED may remove pages of mappings that intersects with
1737 * requested mapping. Account for the pages it would unmap.
1739 nr_pages
= count_vma_pages_range(mm
, addr
, addr
+ len
);
1741 if (!may_expand_vm(mm
, vm_flags
,
1742 (len
>> PAGE_SHIFT
) - nr_pages
))
1746 /* Clear old maps */
1747 while (find_vma_links(mm
, addr
, addr
+ len
, &prev
, &rb_link
,
1749 if (do_munmap(mm
, addr
, len
, uf
))
1754 * Private writable mapping: check memory availability
1756 if (accountable_mapping(file
, vm_flags
)) {
1757 charged
= len
>> PAGE_SHIFT
;
1758 if (security_vm_enough_memory_mm(mm
, charged
))
1760 vm_flags
|= VM_ACCOUNT
;
1764 * Can we just expand an old mapping?
1766 vma
= vma_merge(mm
, prev
, addr
, addr
+ len
, vm_flags
,
1767 NULL
, file
, pgoff
, NULL
, NULL_VM_UFFD_CTX
);
1772 * Determine the object being mapped and call the appropriate
1773 * specific mapper. the address has already been validated, but
1774 * not unmapped, but the maps are removed from the list.
1776 vma
= vm_area_alloc(mm
);
1782 vma
->vm_start
= addr
;
1783 vma
->vm_end
= addr
+ len
;
1784 vma
->vm_flags
= vm_flags
;
1785 vma
->vm_page_prot
= vm_get_page_prot(vm_flags
);
1786 vma
->vm_pgoff
= pgoff
;
1789 if (vm_flags
& VM_DENYWRITE
) {
1790 error
= deny_write_access(file
);
1794 if (vm_flags
& VM_SHARED
) {
1795 error
= mapping_map_writable(file
->f_mapping
);
1797 goto allow_write_and_free_vma
;
1800 /* ->mmap() can change vma->vm_file, but must guarantee that
1801 * vma_link() below can deny write-access if VM_DENYWRITE is set
1802 * and map writably if VM_SHARED is set. This usually means the
1803 * new file must not have been exposed to user-space, yet.
1805 vma
->vm_file
= get_file(file
);
1806 error
= call_mmap(file
, vma
);
1808 goto unmap_and_free_vma
;
1810 /* Can addr have changed??
1812 * Answer: Yes, several device drivers can do it in their
1813 * f_op->mmap method. -DaveM
1814 * Bug: If addr is changed, prev, rb_link, rb_parent should
1815 * be updated for vma_link()
1817 WARN_ON_ONCE(addr
!= vma
->vm_start
);
1819 addr
= vma
->vm_start
;
1820 vm_flags
= vma
->vm_flags
;
1821 } else if (vm_flags
& VM_SHARED
) {
1822 error
= shmem_zero_setup(vma
);
1826 vma_set_anonymous(vma
);
1829 vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
1830 /* Once vma denies write, undo our temporary denial count */
1832 if (vm_flags
& VM_SHARED
)
1833 mapping_unmap_writable(file
->f_mapping
);
1834 if (vm_flags
& VM_DENYWRITE
)
1835 allow_write_access(file
);
1837 file
= vma
->vm_file
;
1839 perf_event_mmap(vma
);
1841 vm_stat_account(mm
, vm_flags
, len
>> PAGE_SHIFT
);
1842 if (vm_flags
& VM_LOCKED
) {
1843 if ((vm_flags
& VM_SPECIAL
) || vma_is_dax(vma
) ||
1844 is_vm_hugetlb_page(vma
) ||
1845 vma
== get_gate_vma(current
->mm
))
1846 vma
->vm_flags
&= VM_LOCKED_CLEAR_MASK
;
1848 mm
->locked_vm
+= (len
>> PAGE_SHIFT
);
1855 * New (or expanded) vma always get soft dirty status.
1856 * Otherwise user-space soft-dirty page tracker won't
1857 * be able to distinguish situation when vma area unmapped,
1858 * then new mapped in-place (which must be aimed as
1859 * a completely new data area).
1861 vma
->vm_flags
|= VM_SOFTDIRTY
;
1863 vma_set_page_prot(vma
);
1868 vma
->vm_file
= NULL
;
1871 /* Undo any partial mapping done by a device driver. */
1872 unmap_region(mm
, vma
, prev
, vma
->vm_start
, vma
->vm_end
);
1874 if (vm_flags
& VM_SHARED
)
1875 mapping_unmap_writable(file
->f_mapping
);
1876 allow_write_and_free_vma
:
1877 if (vm_flags
& VM_DENYWRITE
)
1878 allow_write_access(file
);
1883 vm_unacct_memory(charged
);
1887 unsigned long unmapped_area(struct vm_unmapped_area_info
*info
)
1890 * We implement the search by looking for an rbtree node that
1891 * immediately follows a suitable gap. That is,
1892 * - gap_start = vma->vm_prev->vm_end <= info->high_limit - length;
1893 * - gap_end = vma->vm_start >= info->low_limit + length;
1894 * - gap_end - gap_start >= length
1897 struct mm_struct
*mm
= current
->mm
;
1898 struct vm_area_struct
*vma
;
1899 unsigned long length
, low_limit
, high_limit
, gap_start
, gap_end
;
1901 /* Adjust search length to account for worst case alignment overhead */
1902 length
= info
->length
+ info
->align_mask
;
1903 if (length
< info
->length
)
1906 /* Adjust search limits by the desired length */
1907 if (info
->high_limit
< length
)
1909 high_limit
= info
->high_limit
- length
;
1911 if (info
->low_limit
> high_limit
)
1913 low_limit
= info
->low_limit
+ length
;
1915 /* Check if rbtree root looks promising */
1916 if (RB_EMPTY_ROOT(&mm
->mm_rb
))
1918 vma
= rb_entry(mm
->mm_rb
.rb_node
, struct vm_area_struct
, vm_rb
);
1919 if (vma
->rb_subtree_gap
< length
)
1923 /* Visit left subtree if it looks promising */
1924 gap_end
= vm_start_gap(vma
);
1925 if (gap_end
>= low_limit
&& vma
->vm_rb
.rb_left
) {
1926 struct vm_area_struct
*left
=
1927 rb_entry(vma
->vm_rb
.rb_left
,
1928 struct vm_area_struct
, vm_rb
);
1929 if (left
->rb_subtree_gap
>= length
) {
1935 gap_start
= vma
->vm_prev
? vm_end_gap(vma
->vm_prev
) : 0;
1937 /* Check if current node has a suitable gap */
1938 if (gap_start
> high_limit
)
1940 if (gap_end
>= low_limit
&&
1941 gap_end
> gap_start
&& gap_end
- gap_start
>= length
)
1944 /* Visit right subtree if it looks promising */
1945 if (vma
->vm_rb
.rb_right
) {
1946 struct vm_area_struct
*right
=
1947 rb_entry(vma
->vm_rb
.rb_right
,
1948 struct vm_area_struct
, vm_rb
);
1949 if (right
->rb_subtree_gap
>= length
) {
1955 /* Go back up the rbtree to find next candidate node */
1957 struct rb_node
*prev
= &vma
->vm_rb
;
1958 if (!rb_parent(prev
))
1960 vma
= rb_entry(rb_parent(prev
),
1961 struct vm_area_struct
, vm_rb
);
1962 if (prev
== vma
->vm_rb
.rb_left
) {
1963 gap_start
= vm_end_gap(vma
->vm_prev
);
1964 gap_end
= vm_start_gap(vma
);
1971 /* Check highest gap, which does not precede any rbtree node */
1972 gap_start
= mm
->highest_vm_end
;
1973 gap_end
= ULONG_MAX
; /* Only for VM_BUG_ON below */
1974 if (gap_start
> high_limit
)
1978 /* We found a suitable gap. Clip it with the original low_limit. */
1979 if (gap_start
< info
->low_limit
)
1980 gap_start
= info
->low_limit
;
1982 /* Adjust gap address to the desired alignment */
1983 gap_start
+= (info
->align_offset
- gap_start
) & info
->align_mask
;
1985 VM_BUG_ON(gap_start
+ info
->length
> info
->high_limit
);
1986 VM_BUG_ON(gap_start
+ info
->length
> gap_end
);
1990 unsigned long unmapped_area_topdown(struct vm_unmapped_area_info
*info
)
1992 struct mm_struct
*mm
= current
->mm
;
1993 struct vm_area_struct
*vma
;
1994 unsigned long length
, low_limit
, high_limit
, gap_start
, gap_end
;
1996 /* Adjust search length to account for worst case alignment overhead */
1997 length
= info
->length
+ info
->align_mask
;
1998 if (length
< info
->length
)
2002 * Adjust search limits by the desired length.
2003 * See implementation comment at top of unmapped_area().
2005 gap_end
= info
->high_limit
;
2006 if (gap_end
< length
)
2008 high_limit
= gap_end
- length
;
2010 if (info
->low_limit
> high_limit
)
2012 low_limit
= info
->low_limit
+ length
;
2014 /* Check highest gap, which does not precede any rbtree node */
2015 gap_start
= mm
->highest_vm_end
;
2016 if (gap_start
<= high_limit
)
2019 /* Check if rbtree root looks promising */
2020 if (RB_EMPTY_ROOT(&mm
->mm_rb
))
2022 vma
= rb_entry(mm
->mm_rb
.rb_node
, struct vm_area_struct
, vm_rb
);
2023 if (vma
->rb_subtree_gap
< length
)
2027 /* Visit right subtree if it looks promising */
2028 gap_start
= vma
->vm_prev
? vm_end_gap(vma
->vm_prev
) : 0;
2029 if (gap_start
<= high_limit
&& vma
->vm_rb
.rb_right
) {
2030 struct vm_area_struct
*right
=
2031 rb_entry(vma
->vm_rb
.rb_right
,
2032 struct vm_area_struct
, vm_rb
);
2033 if (right
->rb_subtree_gap
>= length
) {
2040 /* Check if current node has a suitable gap */
2041 gap_end
= vm_start_gap(vma
);
2042 if (gap_end
< low_limit
)
2044 if (gap_start
<= high_limit
&&
2045 gap_end
> gap_start
&& gap_end
- gap_start
>= length
)
2048 /* Visit left subtree if it looks promising */
2049 if (vma
->vm_rb
.rb_left
) {
2050 struct vm_area_struct
*left
=
2051 rb_entry(vma
->vm_rb
.rb_left
,
2052 struct vm_area_struct
, vm_rb
);
2053 if (left
->rb_subtree_gap
>= length
) {
2059 /* Go back up the rbtree to find next candidate node */
2061 struct rb_node
*prev
= &vma
->vm_rb
;
2062 if (!rb_parent(prev
))
2064 vma
= rb_entry(rb_parent(prev
),
2065 struct vm_area_struct
, vm_rb
);
2066 if (prev
== vma
->vm_rb
.rb_right
) {
2067 gap_start
= vma
->vm_prev
?
2068 vm_end_gap(vma
->vm_prev
) : 0;
2075 /* We found a suitable gap. Clip it with the original high_limit. */
2076 if (gap_end
> info
->high_limit
)
2077 gap_end
= info
->high_limit
;
2080 /* Compute highest gap address at the desired alignment */
2081 gap_end
-= info
->length
;
2082 gap_end
-= (gap_end
- info
->align_offset
) & info
->align_mask
;
2084 VM_BUG_ON(gap_end
< info
->low_limit
);
2085 VM_BUG_ON(gap_end
< gap_start
);
2090 #ifndef arch_get_mmap_end
2091 #define arch_get_mmap_end(addr) (TASK_SIZE)
2094 #ifndef arch_get_mmap_base
2095 #define arch_get_mmap_base(addr, base) (base)
2098 /* Get an address range which is currently unmapped.
2099 * For shmat() with addr=0.
2101 * Ugly calling convention alert:
2102 * Return value with the low bits set means error value,
2104 * if (ret & ~PAGE_MASK)
2107 * This function "knows" that -ENOMEM has the bits set.
2109 #ifndef HAVE_ARCH_UNMAPPED_AREA
2111 arch_get_unmapped_area(struct file
*filp
, unsigned long addr
,
2112 unsigned long len
, unsigned long pgoff
, unsigned long flags
)
2114 struct mm_struct
*mm
= current
->mm
;
2115 struct vm_area_struct
*vma
, *prev
;
2116 struct vm_unmapped_area_info info
;
2117 const unsigned long mmap_end
= arch_get_mmap_end(addr
);
2119 if (len
> mmap_end
- mmap_min_addr
)
2122 if (flags
& MAP_FIXED
)
2126 addr
= PAGE_ALIGN(addr
);
2127 vma
= find_vma_prev(mm
, addr
, &prev
);
2128 if (mmap_end
- len
>= addr
&& addr
>= mmap_min_addr
&&
2129 (!vma
|| addr
+ len
<= vm_start_gap(vma
)) &&
2130 (!prev
|| addr
>= vm_end_gap(prev
)))
2136 info
.low_limit
= mm
->mmap_base
;
2137 info
.high_limit
= mmap_end
;
2138 info
.align_mask
= 0;
2139 return vm_unmapped_area(&info
);
2144 * This mmap-allocator allocates new areas top-down from below the
2145 * stack's low limit (the base):
2147 #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
2149 arch_get_unmapped_area_topdown(struct file
*filp
, unsigned long addr
,
2150 unsigned long len
, unsigned long pgoff
,
2151 unsigned long flags
)
2153 struct vm_area_struct
*vma
, *prev
;
2154 struct mm_struct
*mm
= current
->mm
;
2155 struct vm_unmapped_area_info info
;
2156 const unsigned long mmap_end
= arch_get_mmap_end(addr
);
2158 /* requested length too big for entire address space */
2159 if (len
> mmap_end
- mmap_min_addr
)
2162 if (flags
& MAP_FIXED
)
2165 /* requesting a specific address */
2167 addr
= PAGE_ALIGN(addr
);
2168 vma
= find_vma_prev(mm
, addr
, &prev
);
2169 if (mmap_end
- len
>= addr
&& addr
>= mmap_min_addr
&&
2170 (!vma
|| addr
+ len
<= vm_start_gap(vma
)) &&
2171 (!prev
|| addr
>= vm_end_gap(prev
)))
2175 info
.flags
= VM_UNMAPPED_AREA_TOPDOWN
;
2177 info
.low_limit
= max(PAGE_SIZE
, mmap_min_addr
);
2178 info
.high_limit
= arch_get_mmap_base(addr
, mm
->mmap_base
);
2179 info
.align_mask
= 0;
2180 addr
= vm_unmapped_area(&info
);
2183 * A failed mmap() very likely causes application failure,
2184 * so fall back to the bottom-up function here. This scenario
2185 * can happen with large stack limits and large mmap()
2188 if (offset_in_page(addr
)) {
2189 VM_BUG_ON(addr
!= -ENOMEM
);
2191 info
.low_limit
= TASK_UNMAPPED_BASE
;
2192 info
.high_limit
= mmap_end
;
2193 addr
= vm_unmapped_area(&info
);
2201 get_unmapped_area(struct file
*file
, unsigned long addr
, unsigned long len
,
2202 unsigned long pgoff
, unsigned long flags
)
2204 unsigned long (*get_area
)(struct file
*, unsigned long,
2205 unsigned long, unsigned long, unsigned long);
2207 unsigned long error
= arch_mmap_check(addr
, len
, flags
);
2211 /* Careful about overflows.. */
2212 if (len
> TASK_SIZE
)
2215 get_area
= current
->mm
->get_unmapped_area
;
2217 if (file
->f_op
->get_unmapped_area
)
2218 get_area
= file
->f_op
->get_unmapped_area
;
2219 } else if (flags
& MAP_SHARED
) {
2221 * mmap_region() will call shmem_zero_setup() to create a file,
2222 * so use shmem's get_unmapped_area in case it can be huge.
2223 * do_mmap_pgoff() will clear pgoff, so match alignment.
2226 get_area
= shmem_get_unmapped_area
;
2229 addr
= get_area(file
, addr
, len
, pgoff
, flags
);
2230 if (IS_ERR_VALUE(addr
))
2233 if (addr
> TASK_SIZE
- len
)
2235 if (offset_in_page(addr
))
2238 error
= security_mmap_addr(addr
);
2239 return error
? error
: addr
;
2242 EXPORT_SYMBOL(get_unmapped_area
);
2244 /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
2245 struct vm_area_struct
*find_vma(struct mm_struct
*mm
, unsigned long addr
)
2247 struct rb_node
*rb_node
;
2248 struct vm_area_struct
*vma
;
2250 /* Check the cache first. */
2251 vma
= vmacache_find(mm
, addr
);
2255 rb_node
= mm
->mm_rb
.rb_node
;
2258 struct vm_area_struct
*tmp
;
2260 tmp
= rb_entry(rb_node
, struct vm_area_struct
, vm_rb
);
2262 if (tmp
->vm_end
> addr
) {
2264 if (tmp
->vm_start
<= addr
)
2266 rb_node
= rb_node
->rb_left
;
2268 rb_node
= rb_node
->rb_right
;
2272 vmacache_update(addr
, vma
);
2276 EXPORT_SYMBOL(find_vma
);
2279 * Same as find_vma, but also return a pointer to the previous VMA in *pprev.
2281 struct vm_area_struct
*
2282 find_vma_prev(struct mm_struct
*mm
, unsigned long addr
,
2283 struct vm_area_struct
**pprev
)
2285 struct vm_area_struct
*vma
;
2287 vma
= find_vma(mm
, addr
);
2289 *pprev
= vma
->vm_prev
;
2291 struct rb_node
*rb_node
= rb_last(&mm
->mm_rb
);
2293 *pprev
= rb_node
? rb_entry(rb_node
, struct vm_area_struct
, vm_rb
) : NULL
;
2299 * Verify that the stack growth is acceptable and
2300 * update accounting. This is shared with both the
2301 * grow-up and grow-down cases.
2303 static int acct_stack_growth(struct vm_area_struct
*vma
,
2304 unsigned long size
, unsigned long grow
)
2306 struct mm_struct
*mm
= vma
->vm_mm
;
2307 unsigned long new_start
;
2309 /* address space limit tests */
2310 if (!may_expand_vm(mm
, vma
->vm_flags
, grow
))
2313 /* Stack limit test */
2314 if (size
> rlimit(RLIMIT_STACK
))
2317 /* mlock limit tests */
2318 if (vma
->vm_flags
& VM_LOCKED
) {
2319 unsigned long locked
;
2320 unsigned long limit
;
2321 locked
= mm
->locked_vm
+ grow
;
2322 limit
= rlimit(RLIMIT_MEMLOCK
);
2323 limit
>>= PAGE_SHIFT
;
2324 if (locked
> limit
&& !capable(CAP_IPC_LOCK
))
2328 /* Check to ensure the stack will not grow into a hugetlb-only region */
2329 new_start
= (vma
->vm_flags
& VM_GROWSUP
) ? vma
->vm_start
:
2331 if (is_hugepage_only_range(vma
->vm_mm
, new_start
, size
))
2335 * Overcommit.. This must be the final test, as it will
2336 * update security statistics.
2338 if (security_vm_enough_memory_mm(mm
, grow
))
2344 #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
2346 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
2347 * vma is the last one with address > vma->vm_end. Have to extend vma.
2349 int expand_upwards(struct vm_area_struct
*vma
, unsigned long address
)
2351 struct mm_struct
*mm
= vma
->vm_mm
;
2352 struct vm_area_struct
*next
;
2353 unsigned long gap_addr
;
2356 if (!(vma
->vm_flags
& VM_GROWSUP
))
2359 /* Guard against exceeding limits of the address space. */
2360 address
&= PAGE_MASK
;
2361 if (address
>= (TASK_SIZE
& PAGE_MASK
))
2363 address
+= PAGE_SIZE
;
2365 /* Enforce stack_guard_gap */
2366 gap_addr
= address
+ stack_guard_gap
;
2368 /* Guard against overflow */
2369 if (gap_addr
< address
|| gap_addr
> TASK_SIZE
)
2370 gap_addr
= TASK_SIZE
;
2372 next
= vma
->vm_next
;
2373 if (next
&& next
->vm_start
< gap_addr
&&
2374 (next
->vm_flags
& (VM_WRITE
|VM_READ
|VM_EXEC
))) {
2375 if (!(next
->vm_flags
& VM_GROWSUP
))
2377 /* Check that both stack segments have the same anon_vma? */
2380 /* We must make sure the anon_vma is allocated. */
2381 if (unlikely(anon_vma_prepare(vma
)))
2385 * vma->vm_start/vm_end cannot change under us because the caller
2386 * is required to hold the mmap_sem in read mode. We need the
2387 * anon_vma lock to serialize against concurrent expand_stacks.
2389 anon_vma_lock_write(vma
->anon_vma
);
2391 /* Somebody else might have raced and expanded it already */
2392 if (address
> vma
->vm_end
) {
2393 unsigned long size
, grow
;
2395 size
= address
- vma
->vm_start
;
2396 grow
= (address
- vma
->vm_end
) >> PAGE_SHIFT
;
2399 if (vma
->vm_pgoff
+ (size
>> PAGE_SHIFT
) >= vma
->vm_pgoff
) {
2400 error
= acct_stack_growth(vma
, size
, grow
);
2403 * vma_gap_update() doesn't support concurrent
2404 * updates, but we only hold a shared mmap_sem
2405 * lock here, so we need to protect against
2406 * concurrent vma expansions.
2407 * anon_vma_lock_write() doesn't help here, as
2408 * we don't guarantee that all growable vmas
2409 * in a mm share the same root anon vma.
2410 * So, we reuse mm->page_table_lock to guard
2411 * against concurrent vma expansions.
2413 spin_lock(&mm
->page_table_lock
);
2414 if (vma
->vm_flags
& VM_LOCKED
)
2415 mm
->locked_vm
+= grow
;
2416 vm_stat_account(mm
, vma
->vm_flags
, grow
);
2417 anon_vma_interval_tree_pre_update_vma(vma
);
2418 vma
->vm_end
= address
;
2419 anon_vma_interval_tree_post_update_vma(vma
);
2421 vma_gap_update(vma
->vm_next
);
2423 mm
->highest_vm_end
= vm_end_gap(vma
);
2424 spin_unlock(&mm
->page_table_lock
);
2426 perf_event_mmap(vma
);
2430 anon_vma_unlock_write(vma
->anon_vma
);
2431 khugepaged_enter_vma_merge(vma
, vma
->vm_flags
);
2435 #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
2438 * vma is the first one with address < vma->vm_start. Have to extend vma.
2440 int expand_downwards(struct vm_area_struct
*vma
,
2441 unsigned long address
)
2443 struct mm_struct
*mm
= vma
->vm_mm
;
2444 struct vm_area_struct
*prev
;
2447 address
&= PAGE_MASK
;
2448 if (address
< mmap_min_addr
)
2451 /* Enforce stack_guard_gap */
2452 prev
= vma
->vm_prev
;
2453 /* Check that both stack segments have the same anon_vma? */
2454 if (prev
&& !(prev
->vm_flags
& VM_GROWSDOWN
) &&
2455 (prev
->vm_flags
& (VM_WRITE
|VM_READ
|VM_EXEC
))) {
2456 if (address
- prev
->vm_end
< stack_guard_gap
)
2460 /* We must make sure the anon_vma is allocated. */
2461 if (unlikely(anon_vma_prepare(vma
)))
2465 * vma->vm_start/vm_end cannot change under us because the caller
2466 * is required to hold the mmap_sem in read mode. We need the
2467 * anon_vma lock to serialize against concurrent expand_stacks.
2469 anon_vma_lock_write(vma
->anon_vma
);
2471 /* Somebody else might have raced and expanded it already */
2472 if (address
< vma
->vm_start
) {
2473 unsigned long size
, grow
;
2475 size
= vma
->vm_end
- address
;
2476 grow
= (vma
->vm_start
- address
) >> PAGE_SHIFT
;
2479 if (grow
<= vma
->vm_pgoff
) {
2480 error
= acct_stack_growth(vma
, size
, grow
);
2483 * vma_gap_update() doesn't support concurrent
2484 * updates, but we only hold a shared mmap_sem
2485 * lock here, so we need to protect against
2486 * concurrent vma expansions.
2487 * anon_vma_lock_write() doesn't help here, as
2488 * we don't guarantee that all growable vmas
2489 * in a mm share the same root anon vma.
2490 * So, we reuse mm->page_table_lock to guard
2491 * against concurrent vma expansions.
2493 spin_lock(&mm
->page_table_lock
);
2494 if (vma
->vm_flags
& VM_LOCKED
)
2495 mm
->locked_vm
+= grow
;
2496 vm_stat_account(mm
, vma
->vm_flags
, grow
);
2497 anon_vma_interval_tree_pre_update_vma(vma
);
2498 vma
->vm_start
= address
;
2499 vma
->vm_pgoff
-= grow
;
2500 anon_vma_interval_tree_post_update_vma(vma
);
2501 vma_gap_update(vma
);
2502 spin_unlock(&mm
->page_table_lock
);
2504 perf_event_mmap(vma
);
2508 anon_vma_unlock_write(vma
->anon_vma
);
2509 khugepaged_enter_vma_merge(vma
, vma
->vm_flags
);
2514 /* enforced gap between the expanding stack and other mappings. */
2515 unsigned long stack_guard_gap
= 256UL<<PAGE_SHIFT
;
2517 static int __init
cmdline_parse_stack_guard_gap(char *p
)
2522 val
= simple_strtoul(p
, &endptr
, 10);
2524 stack_guard_gap
= val
<< PAGE_SHIFT
;
2528 __setup("stack_guard_gap=", cmdline_parse_stack_guard_gap
);
2530 #ifdef CONFIG_STACK_GROWSUP
2531 int expand_stack(struct vm_area_struct
*vma
, unsigned long address
)
2533 return expand_upwards(vma
, address
);
2536 struct vm_area_struct
*
2537 find_extend_vma(struct mm_struct
*mm
, unsigned long addr
)
2539 struct vm_area_struct
*vma
, *prev
;
2542 vma
= find_vma_prev(mm
, addr
, &prev
);
2543 if (vma
&& (vma
->vm_start
<= addr
))
2545 /* don't alter vm_end if the coredump is running */
2546 if (!prev
|| !mmget_still_valid(mm
) || expand_stack(prev
, addr
))
2548 if (prev
->vm_flags
& VM_LOCKED
)
2549 populate_vma_page_range(prev
, addr
, prev
->vm_end
, NULL
);
2553 int expand_stack(struct vm_area_struct
*vma
, unsigned long address
)
2555 return expand_downwards(vma
, address
);
2558 struct vm_area_struct
*
2559 find_extend_vma(struct mm_struct
*mm
, unsigned long addr
)
2561 struct vm_area_struct
*vma
;
2562 unsigned long start
;
2565 vma
= find_vma(mm
, addr
);
2568 if (vma
->vm_start
<= addr
)
2570 if (!(vma
->vm_flags
& VM_GROWSDOWN
))
2572 /* don't alter vm_start if the coredump is running */
2573 if (!mmget_still_valid(mm
))
2575 start
= vma
->vm_start
;
2576 if (expand_stack(vma
, addr
))
2578 if (vma
->vm_flags
& VM_LOCKED
)
2579 populate_vma_page_range(vma
, addr
, start
, NULL
);
2584 EXPORT_SYMBOL_GPL(find_extend_vma
);
2587 * Ok - we have the memory areas we should free on the vma list,
2588 * so release them, and do the vma updates.
2590 * Called with the mm semaphore held.
2592 static void remove_vma_list(struct mm_struct
*mm
, struct vm_area_struct
*vma
)
2594 unsigned long nr_accounted
= 0;
2596 /* Update high watermark before we lower total_vm */
2597 update_hiwater_vm(mm
);
2599 long nrpages
= vma_pages(vma
);
2601 if (vma
->vm_flags
& VM_ACCOUNT
)
2602 nr_accounted
+= nrpages
;
2603 vm_stat_account(mm
, vma
->vm_flags
, -nrpages
);
2604 vma
= remove_vma(vma
);
2606 vm_unacct_memory(nr_accounted
);
2611 * Get rid of page table information in the indicated region.
2613 * Called with the mm semaphore held.
2615 static void unmap_region(struct mm_struct
*mm
,
2616 struct vm_area_struct
*vma
, struct vm_area_struct
*prev
,
2617 unsigned long start
, unsigned long end
)
2619 struct vm_area_struct
*next
= prev
? prev
->vm_next
: mm
->mmap
;
2620 struct mmu_gather tlb
;
2623 tlb_gather_mmu(&tlb
, mm
, start
, end
);
2624 update_hiwater_rss(mm
);
2625 unmap_vmas(&tlb
, vma
, start
, end
);
2626 free_pgtables(&tlb
, vma
, prev
? prev
->vm_end
: FIRST_USER_ADDRESS
,
2627 next
? next
->vm_start
: USER_PGTABLES_CEILING
);
2628 tlb_finish_mmu(&tlb
, start
, end
);
2632 * Create a list of vma's touched by the unmap, removing them from the mm's
2633 * vma list as we go..
2636 detach_vmas_to_be_unmapped(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2637 struct vm_area_struct
*prev
, unsigned long end
)
2639 struct vm_area_struct
**insertion_point
;
2640 struct vm_area_struct
*tail_vma
= NULL
;
2642 insertion_point
= (prev
? &prev
->vm_next
: &mm
->mmap
);
2643 vma
->vm_prev
= NULL
;
2645 vma_rb_erase(vma
, &mm
->mm_rb
);
2649 } while (vma
&& vma
->vm_start
< end
);
2650 *insertion_point
= vma
;
2652 vma
->vm_prev
= prev
;
2653 vma_gap_update(vma
);
2655 mm
->highest_vm_end
= prev
? vm_end_gap(prev
) : 0;
2656 tail_vma
->vm_next
= NULL
;
2658 /* Kill the cache */
2659 vmacache_invalidate(mm
);
2663 * __split_vma() bypasses sysctl_max_map_count checking. We use this where it
2664 * has already been checked or doesn't make sense to fail.
2666 int __split_vma(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2667 unsigned long addr
, int new_below
)
2669 struct vm_area_struct
*new;
2672 if (vma
->vm_ops
&& vma
->vm_ops
->split
) {
2673 err
= vma
->vm_ops
->split(vma
, addr
);
2678 new = vm_area_dup(vma
);
2685 new->vm_start
= addr
;
2686 new->vm_pgoff
+= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
);
2689 err
= vma_dup_policy(vma
, new);
2693 err
= anon_vma_clone(new, vma
);
2698 get_file(new->vm_file
);
2700 if (new->vm_ops
&& new->vm_ops
->open
)
2701 new->vm_ops
->open(new);
2704 err
= vma_adjust(vma
, addr
, vma
->vm_end
, vma
->vm_pgoff
+
2705 ((addr
- new->vm_start
) >> PAGE_SHIFT
), new);
2707 err
= vma_adjust(vma
, vma
->vm_start
, addr
, vma
->vm_pgoff
, new);
2713 /* Clean everything up if vma_adjust failed. */
2714 if (new->vm_ops
&& new->vm_ops
->close
)
2715 new->vm_ops
->close(new);
2718 unlink_anon_vmas(new);
2720 mpol_put(vma_policy(new));
2727 * Split a vma into two pieces at address 'addr', a new vma is allocated
2728 * either for the first part or the tail.
2730 int split_vma(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2731 unsigned long addr
, int new_below
)
2733 if (mm
->map_count
>= sysctl_max_map_count
)
2736 return __split_vma(mm
, vma
, addr
, new_below
);
2739 /* Munmap is split into 2 main parts -- this part which finds
2740 * what needs doing, and the areas themselves, which do the
2741 * work. This now handles partial unmappings.
2742 * Jeremy Fitzhardinge <jeremy@goop.org>
2744 int __do_munmap(struct mm_struct
*mm
, unsigned long start
, size_t len
,
2745 struct list_head
*uf
, bool downgrade
)
2748 struct vm_area_struct
*vma
, *prev
, *last
;
2750 if ((offset_in_page(start
)) || start
> TASK_SIZE
|| len
> TASK_SIZE
-start
)
2753 len
= PAGE_ALIGN(len
);
2759 * arch_unmap() might do unmaps itself. It must be called
2760 * and finish any rbtree manipulation before this code
2761 * runs and also starts to manipulate the rbtree.
2763 arch_unmap(mm
, start
, end
);
2765 /* Find the first overlapping VMA */
2766 vma
= find_vma(mm
, start
);
2769 prev
= vma
->vm_prev
;
2770 /* we have start < vma->vm_end */
2772 /* if it doesn't overlap, we have nothing.. */
2773 if (vma
->vm_start
>= end
)
2777 * If we need to split any vma, do it now to save pain later.
2779 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
2780 * unmapped vm_area_struct will remain in use: so lower split_vma
2781 * places tmp vma above, and higher split_vma places tmp vma below.
2783 if (start
> vma
->vm_start
) {
2787 * Make sure that map_count on return from munmap() will
2788 * not exceed its limit; but let map_count go just above
2789 * its limit temporarily, to help free resources as expected.
2791 if (end
< vma
->vm_end
&& mm
->map_count
>= sysctl_max_map_count
)
2794 error
= __split_vma(mm
, vma
, start
, 0);
2800 /* Does it split the last one? */
2801 last
= find_vma(mm
, end
);
2802 if (last
&& end
> last
->vm_start
) {
2803 int error
= __split_vma(mm
, last
, end
, 1);
2807 vma
= prev
? prev
->vm_next
: mm
->mmap
;
2811 * If userfaultfd_unmap_prep returns an error the vmas
2812 * will remain splitted, but userland will get a
2813 * highly unexpected error anyway. This is no
2814 * different than the case where the first of the two
2815 * __split_vma fails, but we don't undo the first
2816 * split, despite we could. This is unlikely enough
2817 * failure that it's not worth optimizing it for.
2819 int error
= userfaultfd_unmap_prep(vma
, start
, end
, uf
);
2825 * unlock any mlock()ed ranges before detaching vmas
2827 if (mm
->locked_vm
) {
2828 struct vm_area_struct
*tmp
= vma
;
2829 while (tmp
&& tmp
->vm_start
< end
) {
2830 if (tmp
->vm_flags
& VM_LOCKED
) {
2831 mm
->locked_vm
-= vma_pages(tmp
);
2832 munlock_vma_pages_all(tmp
);
2839 /* Detach vmas from rbtree */
2840 detach_vmas_to_be_unmapped(mm
, vma
, prev
, end
);
2843 downgrade_write(&mm
->mmap_sem
);
2845 unmap_region(mm
, vma
, prev
, start
, end
);
2847 /* Fix up all other VM information */
2848 remove_vma_list(mm
, vma
);
2850 return downgrade
? 1 : 0;
2853 int do_munmap(struct mm_struct
*mm
, unsigned long start
, size_t len
,
2854 struct list_head
*uf
)
2856 return __do_munmap(mm
, start
, len
, uf
, false);
2859 static int __vm_munmap(unsigned long start
, size_t len
, bool downgrade
)
2862 struct mm_struct
*mm
= current
->mm
;
2865 if (down_write_killable(&mm
->mmap_sem
))
2868 ret
= __do_munmap(mm
, start
, len
, &uf
, downgrade
);
2870 * Returning 1 indicates mmap_sem is downgraded.
2871 * But 1 is not legal return value of vm_munmap() and munmap(), reset
2872 * it to 0 before return.
2875 up_read(&mm
->mmap_sem
);
2878 up_write(&mm
->mmap_sem
);
2880 userfaultfd_unmap_complete(mm
, &uf
);
2884 int vm_munmap(unsigned long start
, size_t len
)
2886 return __vm_munmap(start
, len
, false);
2888 EXPORT_SYMBOL(vm_munmap
);
2890 SYSCALL_DEFINE2(munmap
, unsigned long, addr
, size_t, len
)
2892 addr
= untagged_addr(addr
);
2893 profile_munmap(addr
);
2894 return __vm_munmap(addr
, len
, true);
2899 * Emulation of deprecated remap_file_pages() syscall.
2901 SYSCALL_DEFINE5(remap_file_pages
, unsigned long, start
, unsigned long, size
,
2902 unsigned long, prot
, unsigned long, pgoff
, unsigned long, flags
)
2905 struct mm_struct
*mm
= current
->mm
;
2906 struct vm_area_struct
*vma
;
2907 unsigned long populate
= 0;
2908 unsigned long ret
= -EINVAL
;
2911 pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. See Documentation/vm/remap_file_pages.rst.\n",
2912 current
->comm
, current
->pid
);
2916 start
= start
& PAGE_MASK
;
2917 size
= size
& PAGE_MASK
;
2919 if (start
+ size
<= start
)
2922 /* Does pgoff wrap? */
2923 if (pgoff
+ (size
>> PAGE_SHIFT
) < pgoff
)
2926 if (down_write_killable(&mm
->mmap_sem
))
2929 vma
= find_vma(mm
, start
);
2931 if (!vma
|| !(vma
->vm_flags
& VM_SHARED
))
2934 if (start
< vma
->vm_start
)
2937 if (start
+ size
> vma
->vm_end
) {
2938 struct vm_area_struct
*next
;
2940 for (next
= vma
->vm_next
; next
; next
= next
->vm_next
) {
2941 /* hole between vmas ? */
2942 if (next
->vm_start
!= next
->vm_prev
->vm_end
)
2945 if (next
->vm_file
!= vma
->vm_file
)
2948 if (next
->vm_flags
!= vma
->vm_flags
)
2951 if (start
+ size
<= next
->vm_end
)
2959 prot
|= vma
->vm_flags
& VM_READ
? PROT_READ
: 0;
2960 prot
|= vma
->vm_flags
& VM_WRITE
? PROT_WRITE
: 0;
2961 prot
|= vma
->vm_flags
& VM_EXEC
? PROT_EXEC
: 0;
2963 flags
&= MAP_NONBLOCK
;
2964 flags
|= MAP_SHARED
| MAP_FIXED
| MAP_POPULATE
;
2965 if (vma
->vm_flags
& VM_LOCKED
) {
2966 struct vm_area_struct
*tmp
;
2967 flags
|= MAP_LOCKED
;
2969 /* drop PG_Mlocked flag for over-mapped range */
2970 for (tmp
= vma
; tmp
->vm_start
>= start
+ size
;
2971 tmp
= tmp
->vm_next
) {
2973 * Split pmd and munlock page on the border
2976 vma_adjust_trans_huge(tmp
, start
, start
+ size
, 0);
2978 munlock_vma_pages_range(tmp
,
2979 max(tmp
->vm_start
, start
),
2980 min(tmp
->vm_end
, start
+ size
));
2984 file
= get_file(vma
->vm_file
);
2985 ret
= do_mmap_pgoff(vma
->vm_file
, start
, size
,
2986 prot
, flags
, pgoff
, &populate
, NULL
);
2989 up_write(&mm
->mmap_sem
);
2991 mm_populate(ret
, populate
);
2992 if (!IS_ERR_VALUE(ret
))
2998 * this is really a simplified "do_mmap". it only handles
2999 * anonymous maps. eventually we may be able to do some
3000 * brk-specific accounting here.
3002 static int do_brk_flags(unsigned long addr
, unsigned long len
, unsigned long flags
, struct list_head
*uf
)
3004 struct mm_struct
*mm
= current
->mm
;
3005 struct vm_area_struct
*vma
, *prev
;
3006 struct rb_node
**rb_link
, *rb_parent
;
3007 pgoff_t pgoff
= addr
>> PAGE_SHIFT
;
3010 /* Until we need other flags, refuse anything except VM_EXEC. */
3011 if ((flags
& (~VM_EXEC
)) != 0)
3013 flags
|= VM_DATA_DEFAULT_FLAGS
| VM_ACCOUNT
| mm
->def_flags
;
3015 error
= get_unmapped_area(NULL
, addr
, len
, 0, MAP_FIXED
);
3016 if (offset_in_page(error
))
3019 error
= mlock_future_check(mm
, mm
->def_flags
, len
);
3024 * Clear old maps. this also does some error checking for us
3026 while (find_vma_links(mm
, addr
, addr
+ len
, &prev
, &rb_link
,
3028 if (do_munmap(mm
, addr
, len
, uf
))
3032 /* Check against address space limits *after* clearing old maps... */
3033 if (!may_expand_vm(mm
, flags
, len
>> PAGE_SHIFT
))
3036 if (mm
->map_count
> sysctl_max_map_count
)
3039 if (security_vm_enough_memory_mm(mm
, len
>> PAGE_SHIFT
))
3042 /* Can we just expand an old private anonymous mapping? */
3043 vma
= vma_merge(mm
, prev
, addr
, addr
+ len
, flags
,
3044 NULL
, NULL
, pgoff
, NULL
, NULL_VM_UFFD_CTX
);
3049 * create a vma struct for an anonymous mapping
3051 vma
= vm_area_alloc(mm
);
3053 vm_unacct_memory(len
>> PAGE_SHIFT
);
3057 vma_set_anonymous(vma
);
3058 vma
->vm_start
= addr
;
3059 vma
->vm_end
= addr
+ len
;
3060 vma
->vm_pgoff
= pgoff
;
3061 vma
->vm_flags
= flags
;
3062 vma
->vm_page_prot
= vm_get_page_prot(flags
);
3063 vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
3065 perf_event_mmap(vma
);
3066 mm
->total_vm
+= len
>> PAGE_SHIFT
;
3067 mm
->data_vm
+= len
>> PAGE_SHIFT
;
3068 if (flags
& VM_LOCKED
)
3069 mm
->locked_vm
+= (len
>> PAGE_SHIFT
);
3070 vma
->vm_flags
|= VM_SOFTDIRTY
;
3074 int vm_brk_flags(unsigned long addr
, unsigned long request
, unsigned long flags
)
3076 struct mm_struct
*mm
= current
->mm
;
3082 len
= PAGE_ALIGN(request
);
3088 if (down_write_killable(&mm
->mmap_sem
))
3091 ret
= do_brk_flags(addr
, len
, flags
, &uf
);
3092 populate
= ((mm
->def_flags
& VM_LOCKED
) != 0);
3093 up_write(&mm
->mmap_sem
);
3094 userfaultfd_unmap_complete(mm
, &uf
);
3095 if (populate
&& !ret
)
3096 mm_populate(addr
, len
);
3099 EXPORT_SYMBOL(vm_brk_flags
);
3101 int vm_brk(unsigned long addr
, unsigned long len
)
3103 return vm_brk_flags(addr
, len
, 0);
3105 EXPORT_SYMBOL(vm_brk
);
3107 /* Release all mmaps. */
3108 void exit_mmap(struct mm_struct
*mm
)
3110 struct mmu_gather tlb
;
3111 struct vm_area_struct
*vma
;
3112 unsigned long nr_accounted
= 0;
3114 /* mm's last user has gone, and its about to be pulled down */
3115 mmu_notifier_release(mm
);
3117 if (unlikely(mm_is_oom_victim(mm
))) {
3119 * Manually reap the mm to free as much memory as possible.
3120 * Then, as the oom reaper does, set MMF_OOM_SKIP to disregard
3121 * this mm from further consideration. Taking mm->mmap_sem for
3122 * write after setting MMF_OOM_SKIP will guarantee that the oom
3123 * reaper will not run on this mm again after mmap_sem is
3126 * Nothing can be holding mm->mmap_sem here and the above call
3127 * to mmu_notifier_release(mm) ensures mmu notifier callbacks in
3128 * __oom_reap_task_mm() will not block.
3130 * This needs to be done before calling munlock_vma_pages_all(),
3131 * which clears VM_LOCKED, otherwise the oom reaper cannot
3134 (void)__oom_reap_task_mm(mm
);
3136 set_bit(MMF_OOM_SKIP
, &mm
->flags
);
3137 down_write(&mm
->mmap_sem
);
3138 up_write(&mm
->mmap_sem
);
3141 if (mm
->locked_vm
) {
3144 if (vma
->vm_flags
& VM_LOCKED
)
3145 munlock_vma_pages_all(vma
);
3153 if (!vma
) /* Can happen if dup_mmap() received an OOM */
3158 tlb_gather_mmu(&tlb
, mm
, 0, -1);
3159 /* update_hiwater_rss(mm) here? but nobody should be looking */
3160 /* Use -1 here to ensure all VMAs in the mm are unmapped */
3161 unmap_vmas(&tlb
, vma
, 0, -1);
3162 free_pgtables(&tlb
, vma
, FIRST_USER_ADDRESS
, USER_PGTABLES_CEILING
);
3163 tlb_finish_mmu(&tlb
, 0, -1);
3166 * Walk the list again, actually closing and freeing it,
3167 * with preemption enabled, without holding any MM locks.
3170 if (vma
->vm_flags
& VM_ACCOUNT
)
3171 nr_accounted
+= vma_pages(vma
);
3172 vma
= remove_vma(vma
);
3174 vm_unacct_memory(nr_accounted
);
3177 /* Insert vm structure into process list sorted by address
3178 * and into the inode's i_mmap tree. If vm_file is non-NULL
3179 * then i_mmap_rwsem is taken here.
3181 int insert_vm_struct(struct mm_struct
*mm
, struct vm_area_struct
*vma
)
3183 struct vm_area_struct
*prev
;
3184 struct rb_node
**rb_link
, *rb_parent
;
3186 if (find_vma_links(mm
, vma
->vm_start
, vma
->vm_end
,
3187 &prev
, &rb_link
, &rb_parent
))
3189 if ((vma
->vm_flags
& VM_ACCOUNT
) &&
3190 security_vm_enough_memory_mm(mm
, vma_pages(vma
)))
3194 * The vm_pgoff of a purely anonymous vma should be irrelevant
3195 * until its first write fault, when page's anon_vma and index
3196 * are set. But now set the vm_pgoff it will almost certainly
3197 * end up with (unless mremap moves it elsewhere before that
3198 * first wfault), so /proc/pid/maps tells a consistent story.
3200 * By setting it to reflect the virtual start address of the
3201 * vma, merges and splits can happen in a seamless way, just
3202 * using the existing file pgoff checks and manipulations.
3203 * Similarly in do_mmap_pgoff and in do_brk.
3205 if (vma_is_anonymous(vma
)) {
3206 BUG_ON(vma
->anon_vma
);
3207 vma
->vm_pgoff
= vma
->vm_start
>> PAGE_SHIFT
;
3210 vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
3215 * Copy the vma structure to a new location in the same mm,
3216 * prior to moving page table entries, to effect an mremap move.
3218 struct vm_area_struct
*copy_vma(struct vm_area_struct
**vmap
,
3219 unsigned long addr
, unsigned long len
, pgoff_t pgoff
,
3220 bool *need_rmap_locks
)
3222 struct vm_area_struct
*vma
= *vmap
;
3223 unsigned long vma_start
= vma
->vm_start
;
3224 struct mm_struct
*mm
= vma
->vm_mm
;
3225 struct vm_area_struct
*new_vma
, *prev
;
3226 struct rb_node
**rb_link
, *rb_parent
;
3227 bool faulted_in_anon_vma
= true;
3230 * If anonymous vma has not yet been faulted, update new pgoff
3231 * to match new location, to increase its chance of merging.
3233 if (unlikely(vma_is_anonymous(vma
) && !vma
->anon_vma
)) {
3234 pgoff
= addr
>> PAGE_SHIFT
;
3235 faulted_in_anon_vma
= false;
3238 if (find_vma_links(mm
, addr
, addr
+ len
, &prev
, &rb_link
, &rb_parent
))
3239 return NULL
; /* should never get here */
3240 new_vma
= vma_merge(mm
, prev
, addr
, addr
+ len
, vma
->vm_flags
,
3241 vma
->anon_vma
, vma
->vm_file
, pgoff
, vma_policy(vma
),
3242 vma
->vm_userfaultfd_ctx
);
3245 * Source vma may have been merged into new_vma
3247 if (unlikely(vma_start
>= new_vma
->vm_start
&&
3248 vma_start
< new_vma
->vm_end
)) {
3250 * The only way we can get a vma_merge with
3251 * self during an mremap is if the vma hasn't
3252 * been faulted in yet and we were allowed to
3253 * reset the dst vma->vm_pgoff to the
3254 * destination address of the mremap to allow
3255 * the merge to happen. mremap must change the
3256 * vm_pgoff linearity between src and dst vmas
3257 * (in turn preventing a vma_merge) to be
3258 * safe. It is only safe to keep the vm_pgoff
3259 * linear if there are no pages mapped yet.
3261 VM_BUG_ON_VMA(faulted_in_anon_vma
, new_vma
);
3262 *vmap
= vma
= new_vma
;
3264 *need_rmap_locks
= (new_vma
->vm_pgoff
<= vma
->vm_pgoff
);
3266 new_vma
= vm_area_dup(vma
);
3269 new_vma
->vm_start
= addr
;
3270 new_vma
->vm_end
= addr
+ len
;
3271 new_vma
->vm_pgoff
= pgoff
;
3272 if (vma_dup_policy(vma
, new_vma
))
3274 if (anon_vma_clone(new_vma
, vma
))
3275 goto out_free_mempol
;
3276 if (new_vma
->vm_file
)
3277 get_file(new_vma
->vm_file
);
3278 if (new_vma
->vm_ops
&& new_vma
->vm_ops
->open
)
3279 new_vma
->vm_ops
->open(new_vma
);
3280 vma_link(mm
, new_vma
, prev
, rb_link
, rb_parent
);
3281 *need_rmap_locks
= false;
3286 mpol_put(vma_policy(new_vma
));
3288 vm_area_free(new_vma
);
3294 * Return true if the calling process may expand its vm space by the passed
3297 bool may_expand_vm(struct mm_struct
*mm
, vm_flags_t flags
, unsigned long npages
)
3299 if (mm
->total_vm
+ npages
> rlimit(RLIMIT_AS
) >> PAGE_SHIFT
)
3302 if (is_data_mapping(flags
) &&
3303 mm
->data_vm
+ npages
> rlimit(RLIMIT_DATA
) >> PAGE_SHIFT
) {
3304 /* Workaround for Valgrind */
3305 if (rlimit(RLIMIT_DATA
) == 0 &&
3306 mm
->data_vm
+ npages
<= rlimit_max(RLIMIT_DATA
) >> PAGE_SHIFT
)
3309 pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits%s.\n",
3310 current
->comm
, current
->pid
,
3311 (mm
->data_vm
+ npages
) << PAGE_SHIFT
,
3312 rlimit(RLIMIT_DATA
),
3313 ignore_rlimit_data
? "" : " or use boot option ignore_rlimit_data");
3315 if (!ignore_rlimit_data
)
3322 void vm_stat_account(struct mm_struct
*mm
, vm_flags_t flags
, long npages
)
3324 mm
->total_vm
+= npages
;
3326 if (is_exec_mapping(flags
))
3327 mm
->exec_vm
+= npages
;
3328 else if (is_stack_mapping(flags
))
3329 mm
->stack_vm
+= npages
;
3330 else if (is_data_mapping(flags
))
3331 mm
->data_vm
+= npages
;
3334 static vm_fault_t
special_mapping_fault(struct vm_fault
*vmf
);
3337 * Having a close hook prevents vma merging regardless of flags.
3339 static void special_mapping_close(struct vm_area_struct
*vma
)
3343 static const char *special_mapping_name(struct vm_area_struct
*vma
)
3345 return ((struct vm_special_mapping
*)vma
->vm_private_data
)->name
;
3348 static int special_mapping_mremap(struct vm_area_struct
*new_vma
)
3350 struct vm_special_mapping
*sm
= new_vma
->vm_private_data
;
3352 if (WARN_ON_ONCE(current
->mm
!= new_vma
->vm_mm
))
3356 return sm
->mremap(sm
, new_vma
);
3361 static const struct vm_operations_struct special_mapping_vmops
= {
3362 .close
= special_mapping_close
,
3363 .fault
= special_mapping_fault
,
3364 .mremap
= special_mapping_mremap
,
3365 .name
= special_mapping_name
,
3368 static const struct vm_operations_struct legacy_special_mapping_vmops
= {
3369 .close
= special_mapping_close
,
3370 .fault
= special_mapping_fault
,
3373 static vm_fault_t
special_mapping_fault(struct vm_fault
*vmf
)
3375 struct vm_area_struct
*vma
= vmf
->vma
;
3377 struct page
**pages
;
3379 if (vma
->vm_ops
== &legacy_special_mapping_vmops
) {
3380 pages
= vma
->vm_private_data
;
3382 struct vm_special_mapping
*sm
= vma
->vm_private_data
;
3385 return sm
->fault(sm
, vmf
->vma
, vmf
);
3390 for (pgoff
= vmf
->pgoff
; pgoff
&& *pages
; ++pages
)
3394 struct page
*page
= *pages
;
3400 return VM_FAULT_SIGBUS
;
3403 static struct vm_area_struct
*__install_special_mapping(
3404 struct mm_struct
*mm
,
3405 unsigned long addr
, unsigned long len
,
3406 unsigned long vm_flags
, void *priv
,
3407 const struct vm_operations_struct
*ops
)
3410 struct vm_area_struct
*vma
;
3412 vma
= vm_area_alloc(mm
);
3413 if (unlikely(vma
== NULL
))
3414 return ERR_PTR(-ENOMEM
);
3416 vma
->vm_start
= addr
;
3417 vma
->vm_end
= addr
+ len
;
3419 vma
->vm_flags
= vm_flags
| mm
->def_flags
| VM_DONTEXPAND
| VM_SOFTDIRTY
;
3420 vma
->vm_page_prot
= vm_get_page_prot(vma
->vm_flags
);
3423 vma
->vm_private_data
= priv
;
3425 ret
= insert_vm_struct(mm
, vma
);
3429 vm_stat_account(mm
, vma
->vm_flags
, len
>> PAGE_SHIFT
);
3431 perf_event_mmap(vma
);
3437 return ERR_PTR(ret
);
3440 bool vma_is_special_mapping(const struct vm_area_struct
*vma
,
3441 const struct vm_special_mapping
*sm
)
3443 return vma
->vm_private_data
== sm
&&
3444 (vma
->vm_ops
== &special_mapping_vmops
||
3445 vma
->vm_ops
== &legacy_special_mapping_vmops
);
3449 * Called with mm->mmap_sem held for writing.
3450 * Insert a new vma covering the given region, with the given flags.
3451 * Its pages are supplied by the given array of struct page *.
3452 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
3453 * The region past the last page supplied will always produce SIGBUS.
3454 * The array pointer and the pages it points to are assumed to stay alive
3455 * for as long as this mapping might exist.
3457 struct vm_area_struct
*_install_special_mapping(
3458 struct mm_struct
*mm
,
3459 unsigned long addr
, unsigned long len
,
3460 unsigned long vm_flags
, const struct vm_special_mapping
*spec
)
3462 return __install_special_mapping(mm
, addr
, len
, vm_flags
, (void *)spec
,
3463 &special_mapping_vmops
);
3466 int install_special_mapping(struct mm_struct
*mm
,
3467 unsigned long addr
, unsigned long len
,
3468 unsigned long vm_flags
, struct page
**pages
)
3470 struct vm_area_struct
*vma
= __install_special_mapping(
3471 mm
, addr
, len
, vm_flags
, (void *)pages
,
3472 &legacy_special_mapping_vmops
);
3474 return PTR_ERR_OR_ZERO(vma
);
3477 static DEFINE_MUTEX(mm_all_locks_mutex
);
3479 static void vm_lock_anon_vma(struct mm_struct
*mm
, struct anon_vma
*anon_vma
)
3481 if (!test_bit(0, (unsigned long *) &anon_vma
->root
->rb_root
.rb_root
.rb_node
)) {
3483 * The LSB of head.next can't change from under us
3484 * because we hold the mm_all_locks_mutex.
3486 down_write_nest_lock(&anon_vma
->root
->rwsem
, &mm
->mmap_sem
);
3488 * We can safely modify head.next after taking the
3489 * anon_vma->root->rwsem. If some other vma in this mm shares
3490 * the same anon_vma we won't take it again.
3492 * No need of atomic instructions here, head.next
3493 * can't change from under us thanks to the
3494 * anon_vma->root->rwsem.
3496 if (__test_and_set_bit(0, (unsigned long *)
3497 &anon_vma
->root
->rb_root
.rb_root
.rb_node
))
3502 static void vm_lock_mapping(struct mm_struct
*mm
, struct address_space
*mapping
)
3504 if (!test_bit(AS_MM_ALL_LOCKS
, &mapping
->flags
)) {
3506 * AS_MM_ALL_LOCKS can't change from under us because
3507 * we hold the mm_all_locks_mutex.
3509 * Operations on ->flags have to be atomic because
3510 * even if AS_MM_ALL_LOCKS is stable thanks to the
3511 * mm_all_locks_mutex, there may be other cpus
3512 * changing other bitflags in parallel to us.
3514 if (test_and_set_bit(AS_MM_ALL_LOCKS
, &mapping
->flags
))
3516 down_write_nest_lock(&mapping
->i_mmap_rwsem
, &mm
->mmap_sem
);
3521 * This operation locks against the VM for all pte/vma/mm related
3522 * operations that could ever happen on a certain mm. This includes
3523 * vmtruncate, try_to_unmap, and all page faults.
3525 * The caller must take the mmap_sem in write mode before calling
3526 * mm_take_all_locks(). The caller isn't allowed to release the
3527 * mmap_sem until mm_drop_all_locks() returns.
3529 * mmap_sem in write mode is required in order to block all operations
3530 * that could modify pagetables and free pages without need of
3531 * altering the vma layout. It's also needed in write mode to avoid new
3532 * anon_vmas to be associated with existing vmas.
3534 * A single task can't take more than one mm_take_all_locks() in a row
3535 * or it would deadlock.
3537 * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in
3538 * mapping->flags avoid to take the same lock twice, if more than one
3539 * vma in this mm is backed by the same anon_vma or address_space.
3541 * We take locks in following order, accordingly to comment at beginning
3543 * - all hugetlbfs_i_mmap_rwsem_key locks (aka mapping->i_mmap_rwsem for
3545 * - all i_mmap_rwsem locks;
3546 * - all anon_vma->rwseml
3548 * We can take all locks within these types randomly because the VM code
3549 * doesn't nest them and we protected from parallel mm_take_all_locks() by
3550 * mm_all_locks_mutex.
3552 * mm_take_all_locks() and mm_drop_all_locks are expensive operations
3553 * that may have to take thousand of locks.
3555 * mm_take_all_locks() can fail if it's interrupted by signals.
3557 int mm_take_all_locks(struct mm_struct
*mm
)
3559 struct vm_area_struct
*vma
;
3560 struct anon_vma_chain
*avc
;
3562 BUG_ON(down_read_trylock(&mm
->mmap_sem
));
3564 mutex_lock(&mm_all_locks_mutex
);
3566 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
3567 if (signal_pending(current
))
3569 if (vma
->vm_file
&& vma
->vm_file
->f_mapping
&&
3570 is_vm_hugetlb_page(vma
))
3571 vm_lock_mapping(mm
, vma
->vm_file
->f_mapping
);
3574 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
3575 if (signal_pending(current
))
3577 if (vma
->vm_file
&& vma
->vm_file
->f_mapping
&&
3578 !is_vm_hugetlb_page(vma
))
3579 vm_lock_mapping(mm
, vma
->vm_file
->f_mapping
);
3582 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
3583 if (signal_pending(current
))
3586 list_for_each_entry(avc
, &vma
->anon_vma_chain
, same_vma
)
3587 vm_lock_anon_vma(mm
, avc
->anon_vma
);
3593 mm_drop_all_locks(mm
);
3597 static void vm_unlock_anon_vma(struct anon_vma
*anon_vma
)
3599 if (test_bit(0, (unsigned long *) &anon_vma
->root
->rb_root
.rb_root
.rb_node
)) {
3601 * The LSB of head.next can't change to 0 from under
3602 * us because we hold the mm_all_locks_mutex.
3604 * We must however clear the bitflag before unlocking
3605 * the vma so the users using the anon_vma->rb_root will
3606 * never see our bitflag.
3608 * No need of atomic instructions here, head.next
3609 * can't change from under us until we release the
3610 * anon_vma->root->rwsem.
3612 if (!__test_and_clear_bit(0, (unsigned long *)
3613 &anon_vma
->root
->rb_root
.rb_root
.rb_node
))
3615 anon_vma_unlock_write(anon_vma
);
3619 static void vm_unlock_mapping(struct address_space
*mapping
)
3621 if (test_bit(AS_MM_ALL_LOCKS
, &mapping
->flags
)) {
3623 * AS_MM_ALL_LOCKS can't change to 0 from under us
3624 * because we hold the mm_all_locks_mutex.
3626 i_mmap_unlock_write(mapping
);
3627 if (!test_and_clear_bit(AS_MM_ALL_LOCKS
,
3634 * The mmap_sem cannot be released by the caller until
3635 * mm_drop_all_locks() returns.
3637 void mm_drop_all_locks(struct mm_struct
*mm
)
3639 struct vm_area_struct
*vma
;
3640 struct anon_vma_chain
*avc
;
3642 BUG_ON(down_read_trylock(&mm
->mmap_sem
));
3643 BUG_ON(!mutex_is_locked(&mm_all_locks_mutex
));
3645 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
3647 list_for_each_entry(avc
, &vma
->anon_vma_chain
, same_vma
)
3648 vm_unlock_anon_vma(avc
->anon_vma
);
3649 if (vma
->vm_file
&& vma
->vm_file
->f_mapping
)
3650 vm_unlock_mapping(vma
->vm_file
->f_mapping
);
3653 mutex_unlock(&mm_all_locks_mutex
);
3657 * initialise the percpu counter for VM
3659 void __init
mmap_init(void)
3663 ret
= percpu_counter_init(&vm_committed_as
, 0, GFP_KERNEL
);
3668 * Initialise sysctl_user_reserve_kbytes.
3670 * This is intended to prevent a user from starting a single memory hogging
3671 * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
3674 * The default value is min(3% of free memory, 128MB)
3675 * 128MB is enough to recover with sshd/login, bash, and top/kill.
3677 static int init_user_reserve(void)
3679 unsigned long free_kbytes
;
3681 free_kbytes
= global_zone_page_state(NR_FREE_PAGES
) << (PAGE_SHIFT
- 10);
3683 sysctl_user_reserve_kbytes
= min(free_kbytes
/ 32, 1UL << 17);
3686 subsys_initcall(init_user_reserve
);
3689 * Initialise sysctl_admin_reserve_kbytes.
3691 * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
3692 * to log in and kill a memory hogging process.
3694 * Systems with more than 256MB will reserve 8MB, enough to recover
3695 * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
3696 * only reserve 3% of free pages by default.
3698 static int init_admin_reserve(void)
3700 unsigned long free_kbytes
;
3702 free_kbytes
= global_zone_page_state(NR_FREE_PAGES
) << (PAGE_SHIFT
- 10);
3704 sysctl_admin_reserve_kbytes
= min(free_kbytes
/ 32, 1UL << 13);
3707 subsys_initcall(init_admin_reserve
);
3710 * Reinititalise user and admin reserves if memory is added or removed.
3712 * The default user reserve max is 128MB, and the default max for the
3713 * admin reserve is 8MB. These are usually, but not always, enough to
3714 * enable recovery from a memory hogging process using login/sshd, a shell,
3715 * and tools like top. It may make sense to increase or even disable the
3716 * reserve depending on the existence of swap or variations in the recovery
3717 * tools. So, the admin may have changed them.
3719 * If memory is added and the reserves have been eliminated or increased above
3720 * the default max, then we'll trust the admin.
3722 * If memory is removed and there isn't enough free memory, then we
3723 * need to reset the reserves.
3725 * Otherwise keep the reserve set by the admin.
3727 static int reserve_mem_notifier(struct notifier_block
*nb
,
3728 unsigned long action
, void *data
)
3730 unsigned long tmp
, free_kbytes
;
3734 /* Default max is 128MB. Leave alone if modified by operator. */
3735 tmp
= sysctl_user_reserve_kbytes
;
3736 if (0 < tmp
&& tmp
< (1UL << 17))
3737 init_user_reserve();
3739 /* Default max is 8MB. Leave alone if modified by operator. */
3740 tmp
= sysctl_admin_reserve_kbytes
;
3741 if (0 < tmp
&& tmp
< (1UL << 13))
3742 init_admin_reserve();
3746 free_kbytes
= global_zone_page_state(NR_FREE_PAGES
) << (PAGE_SHIFT
- 10);
3748 if (sysctl_user_reserve_kbytes
> free_kbytes
) {
3749 init_user_reserve();
3750 pr_info("vm.user_reserve_kbytes reset to %lu\n",
3751 sysctl_user_reserve_kbytes
);
3754 if (sysctl_admin_reserve_kbytes
> free_kbytes
) {
3755 init_admin_reserve();
3756 pr_info("vm.admin_reserve_kbytes reset to %lu\n",
3757 sysctl_admin_reserve_kbytes
);
3766 static struct notifier_block reserve_mem_nb
= {
3767 .notifier_call
= reserve_mem_notifier
,
3770 static int __meminit
init_reserve_notifier(void)
3772 if (register_hotmemory_notifier(&reserve_mem_nb
))
3773 pr_err("Failed registering memory add/remove notifier for admin reserve\n");
3777 subsys_initcall(init_reserve_notifier
);