1 // SPDX-License-Identifier: GPL-2.0
5 * (C) Copyright 1994 Linus Torvalds
6 * (C) Copyright 2002 Christoph Hellwig
8 * Address space accounting code <alan@lxorguk.ukuu.org.uk>
9 * (C) Copyright 2002 Red Hat Inc, All Rights Reserved
12 #include <linux/pagewalk.h>
13 #include <linux/hugetlb.h>
14 #include <linux/shm.h>
15 #include <linux/mman.h>
17 #include <linux/highmem.h>
18 #include <linux/security.h>
19 #include <linux/mempolicy.h>
20 #include <linux/personality.h>
21 #include <linux/syscalls.h>
22 #include <linux/swap.h>
23 #include <linux/swapops.h>
24 #include <linux/mmu_notifier.h>
25 #include <linux/migrate.h>
26 #include <linux/perf_event.h>
27 #include <linux/pkeys.h>
28 #include <linux/ksm.h>
29 #include <linux/uaccess.h>
30 #include <linux/mm_inline.h>
31 #include <linux/pgtable.h>
32 #include <linux/sched/sysctl.h>
33 #include <linux/userfaultfd_k.h>
34 #include <linux/memory-tiers.h>
35 #include <asm/cacheflush.h>
36 #include <asm/mmu_context.h>
37 #include <asm/tlbflush.h>
42 static inline bool can_change_pte_writable(struct vm_area_struct *vma,
43 unsigned long addr, pte_t pte)
47 if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE)))
50 /* Don't touch entries that are not even readable. */
51 if (pte_protnone(pte))
54 /* Do we need write faults for softdirty tracking? */
55 if (vma_soft_dirty_enabled(vma) && !pte_soft_dirty(pte))
58 /* Do we need write faults for uffd-wp tracking? */
59 if (userfaultfd_pte_wp(vma, pte))
62 if (!(vma->vm_flags & VM_SHARED)) {
64 * Writable MAP_PRIVATE mapping: We can only special-case on
65 * exclusive anonymous pages, because we know that our
66 * write-fault handler similarly would map them writable without
67 * any additional checks while holding the PT lock.
69 page = vm_normal_page(vma, addr, pte);
70 return page && PageAnon(page) && PageAnonExclusive(page);
74 * Writable MAP_SHARED mapping: "clean" might indicate that the FS still
75 * needs a real write-fault for writenotify
76 * (see vma_wants_writenotify()). If "dirty", the assumption is that the
77 * FS was already notified and we can simply mark the PTE writable
78 * just like the write-fault handler would do.
80 return pte_dirty(pte);
83 static unsigned long change_pte_range(struct mmu_gather *tlb,
84 struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr,
85 unsigned long end, pgprot_t newprot, unsigned long cp_flags)
89 unsigned long pages = 0;
90 int target_node = NUMA_NO_NODE;
91 bool prot_numa = cp_flags & MM_CP_PROT_NUMA;
92 bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
93 bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;
95 tlb_change_page_size(tlb, PAGE_SIZE);
98 * Can be called with only the mmap_lock for reading by
99 * prot_numa so we must check the pmd isn't constantly
100 * changing from under us from pmd_none to pmd_trans_huge
101 * and/or the other way around.
103 if (pmd_trans_unstable(pmd))
107 * The pmd points to a regular pte so the pmd can't change
108 * from under us even if the mmap_lock is only hold for
111 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
113 /* Get target node for single threaded private VMAs */
114 if (prot_numa && !(vma->vm_flags & VM_SHARED) &&
115 atomic_read(&vma->vm_mm->mm_users) == 1)
116 target_node = numa_node_id();
118 flush_tlb_batched_pending(vma->vm_mm);
119 arch_enter_lazy_mmu_mode();
122 if (pte_present(oldpte)) {
124 bool preserve_write = prot_numa && pte_write(oldpte);
127 * Avoid trapping faults against the zero or KSM
128 * pages. See similar comment in change_huge_pmd.
135 /* Avoid TLB flush if possible */
136 if (pte_protnone(oldpte))
139 page = vm_normal_page(vma, addr, oldpte);
140 if (!page || is_zone_device_page(page) || PageKsm(page))
143 /* Also skip shared copy-on-write pages */
144 if (is_cow_mapping(vma->vm_flags) &&
145 page_count(page) != 1)
149 * While migration can move some dirty pages,
150 * it cannot move them all from MIGRATE_ASYNC
153 if (page_is_file_lru(page) && PageDirty(page))
157 * Don't mess with PTEs if page is already on the node
158 * a single-threaded process is running on.
160 nid = page_to_nid(page);
161 if (target_node == nid)
163 toptier = node_is_toptier(nid);
166 * Skip scanning top tier node if normal numa
167 * balancing is disabled
169 if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) &&
172 if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING &&
174 xchg_page_access_time(page,
175 jiffies_to_msecs(jiffies));
178 oldpte = ptep_modify_prot_start(vma, addr, pte);
179 ptent = pte_modify(oldpte, newprot);
181 ptent = pte_mk_savedwrite(ptent);
184 ptent = pte_wrprotect(ptent);
185 ptent = pte_mkuffd_wp(ptent);
186 } else if (uffd_wp_resolve) {
187 ptent = pte_clear_uffd_wp(ptent);
191 * In some writable, shared mappings, we might want
192 * to catch actual write access -- see
193 * vma_wants_writenotify().
195 * In all writable, private mappings, we have to
196 * properly handle COW.
198 * In both cases, we can sometimes still change PTEs
199 * writable and avoid the write-fault handler, for
200 * example, if a PTE is already dirty and no other
201 * COW or special handling is required.
203 if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) &&
205 can_change_pte_writable(vma, addr, ptent))
206 ptent = pte_mkwrite(ptent);
208 ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent);
209 if (pte_needs_flush(oldpte, ptent))
210 tlb_flush_pte_range(tlb, addr, PAGE_SIZE);
212 } else if (is_swap_pte(oldpte)) {
213 swp_entry_t entry = pte_to_swp_entry(oldpte);
216 if (is_writable_migration_entry(entry)) {
217 struct page *page = pfn_swap_entry_to_page(entry);
220 * A protection check is difficult so
221 * just be safe and disable write
224 entry = make_readable_exclusive_migration_entry(
227 entry = make_readable_migration_entry(swp_offset(entry));
228 newpte = swp_entry_to_pte(entry);
229 if (pte_swp_soft_dirty(oldpte))
230 newpte = pte_swp_mksoft_dirty(newpte);
231 if (pte_swp_uffd_wp(oldpte))
232 newpte = pte_swp_mkuffd_wp(newpte);
233 } else if (is_writable_device_private_entry(entry)) {
235 * We do not preserve soft-dirtiness. See
236 * copy_one_pte() for explanation.
238 entry = make_readable_device_private_entry(
240 newpte = swp_entry_to_pte(entry);
241 if (pte_swp_uffd_wp(oldpte))
242 newpte = pte_swp_mkuffd_wp(newpte);
243 } else if (is_writable_device_exclusive_entry(entry)) {
244 entry = make_readable_device_exclusive_entry(
246 newpte = swp_entry_to_pte(entry);
247 if (pte_swp_soft_dirty(oldpte))
248 newpte = pte_swp_mksoft_dirty(newpte);
249 if (pte_swp_uffd_wp(oldpte))
250 newpte = pte_swp_mkuffd_wp(newpte);
251 } else if (pte_marker_entry_uffd_wp(entry)) {
253 * If this is uffd-wp pte marker and we'd like
254 * to unprotect it, drop it; the next page
255 * fault will trigger without uffd trapping.
257 if (uffd_wp_resolve) {
258 pte_clear(vma->vm_mm, addr, pte);
267 newpte = pte_swp_mkuffd_wp(newpte);
268 else if (uffd_wp_resolve)
269 newpte = pte_swp_clear_uffd_wp(newpte);
271 if (!pte_same(oldpte, newpte)) {
272 set_pte_at(vma->vm_mm, addr, pte, newpte);
276 /* It must be an none page, or what else?.. */
277 WARN_ON_ONCE(!pte_none(oldpte));
278 if (unlikely(uffd_wp && !vma_is_anonymous(vma))) {
280 * For file-backed mem, we need to be able to
281 * wr-protect a none pte, because even if the
282 * pte is none, the page/swap cache could
283 * exist. Doing that by install a marker.
285 set_pte_at(vma->vm_mm, addr, pte,
286 make_pte_marker(PTE_MARKER_UFFD_WP));
290 } while (pte++, addr += PAGE_SIZE, addr != end);
291 arch_leave_lazy_mmu_mode();
292 pte_unmap_unlock(pte - 1, ptl);
298 * Used when setting automatic NUMA hinting protection where it is
299 * critical that a numa hinting PMD is not confused with a bad PMD.
301 static inline int pmd_none_or_clear_bad_unless_trans_huge(pmd_t *pmd)
303 pmd_t pmdval = pmd_read_atomic(pmd);
305 /* See pmd_none_or_trans_huge_or_clear_bad for info on barrier */
306 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
310 if (pmd_none(pmdval))
312 if (pmd_trans_huge(pmdval))
314 if (unlikely(pmd_bad(pmdval))) {
322 /* Return true if we're uffd wr-protecting file-backed memory, or false */
324 uffd_wp_protect_file(struct vm_area_struct *vma, unsigned long cp_flags)
326 return (cp_flags & MM_CP_UFFD_WP) && !vma_is_anonymous(vma);
330 * If wr-protecting the range for file-backed, populate pgtable for the case
331 * when pgtable is empty but page cache exists. When {pte|pmd|...}_alloc()
332 * failed it means no memory, we don't have a better option but stop.
334 #define change_pmd_prepare(vma, pmd, cp_flags) \
336 if (unlikely(uffd_wp_protect_file(vma, cp_flags))) { \
337 if (WARN_ON_ONCE(pte_alloc(vma->vm_mm, pmd))) \
342 * This is the general pud/p4d/pgd version of change_pmd_prepare(). We need to
343 * have separate change_pmd_prepare() because pte_alloc() returns 0 on success,
344 * while {pmd|pud|p4d}_alloc() returns the valid pointer on success.
346 #define change_prepare(vma, high, low, addr, cp_flags) \
348 if (unlikely(uffd_wp_protect_file(vma, cp_flags))) { \
349 low##_t *p = low##_alloc(vma->vm_mm, high, addr); \
350 if (WARN_ON_ONCE(p == NULL)) \
355 static inline unsigned long change_pmd_range(struct mmu_gather *tlb,
356 struct vm_area_struct *vma, pud_t *pud, unsigned long addr,
357 unsigned long end, pgprot_t newprot, unsigned long cp_flags)
361 unsigned long pages = 0;
362 unsigned long nr_huge_updates = 0;
363 struct mmu_notifier_range range;
367 pmd = pmd_offset(pud, addr);
369 unsigned long this_pages;
371 next = pmd_addr_end(addr, end);
373 change_pmd_prepare(vma, pmd, cp_flags);
375 * Automatic NUMA balancing walks the tables with mmap_lock
376 * held for read. It's possible a parallel update to occur
377 * between pmd_trans_huge() and a pmd_none_or_clear_bad()
378 * check leading to a false positive and clearing.
379 * Hence, it's necessary to atomically read the PMD value
380 * for all the checks.
382 if (!is_swap_pmd(*pmd) && !pmd_devmap(*pmd) &&
383 pmd_none_or_clear_bad_unless_trans_huge(pmd))
386 /* invoke the mmu notifier if the pmd is populated */
388 mmu_notifier_range_init(&range,
389 MMU_NOTIFY_PROTECTION_VMA, 0,
390 vma, vma->vm_mm, addr, end);
391 mmu_notifier_invalidate_range_start(&range);
394 if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
395 if ((next - addr != HPAGE_PMD_SIZE) ||
396 uffd_wp_protect_file(vma, cp_flags)) {
397 __split_huge_pmd(vma, pmd, addr, false, NULL);
399 * For file-backed, the pmd could have been
400 * cleared; make sure pmd populated if
401 * necessary, then fall-through to pte level.
403 change_pmd_prepare(vma, pmd, cp_flags);
406 * change_huge_pmd() does not defer TLB flushes,
407 * so no need to propagate the tlb argument.
409 int nr_ptes = change_huge_pmd(tlb, vma, pmd,
410 addr, newprot, cp_flags);
413 if (nr_ptes == HPAGE_PMD_NR) {
414 pages += HPAGE_PMD_NR;
418 /* huge pmd was handled */
422 /* fall through, the trans huge pmd just split */
424 this_pages = change_pte_range(tlb, vma, pmd, addr, next,
429 } while (pmd++, addr = next, addr != end);
432 mmu_notifier_invalidate_range_end(&range);
435 count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates);
439 static inline unsigned long change_pud_range(struct mmu_gather *tlb,
440 struct vm_area_struct *vma, p4d_t *p4d, unsigned long addr,
441 unsigned long end, pgprot_t newprot, unsigned long cp_flags)
445 unsigned long pages = 0;
447 pud = pud_offset(p4d, addr);
449 next = pud_addr_end(addr, end);
450 change_prepare(vma, pud, pmd, addr, cp_flags);
451 if (pud_none_or_clear_bad(pud))
453 pages += change_pmd_range(tlb, vma, pud, addr, next, newprot,
455 } while (pud++, addr = next, addr != end);
460 static inline unsigned long change_p4d_range(struct mmu_gather *tlb,
461 struct vm_area_struct *vma, pgd_t *pgd, unsigned long addr,
462 unsigned long end, pgprot_t newprot, unsigned long cp_flags)
466 unsigned long pages = 0;
468 p4d = p4d_offset(pgd, addr);
470 next = p4d_addr_end(addr, end);
471 change_prepare(vma, p4d, pud, addr, cp_flags);
472 if (p4d_none_or_clear_bad(p4d))
474 pages += change_pud_range(tlb, vma, p4d, addr, next, newprot,
476 } while (p4d++, addr = next, addr != end);
481 static unsigned long change_protection_range(struct mmu_gather *tlb,
482 struct vm_area_struct *vma, unsigned long addr,
483 unsigned long end, pgprot_t newprot, unsigned long cp_flags)
485 struct mm_struct *mm = vma->vm_mm;
488 unsigned long pages = 0;
491 pgd = pgd_offset(mm, addr);
492 tlb_start_vma(tlb, vma);
494 next = pgd_addr_end(addr, end);
495 change_prepare(vma, pgd, p4d, addr, cp_flags);
496 if (pgd_none_or_clear_bad(pgd))
498 pages += change_p4d_range(tlb, vma, pgd, addr, next, newprot,
500 } while (pgd++, addr = next, addr != end);
502 tlb_end_vma(tlb, vma);
507 unsigned long change_protection(struct mmu_gather *tlb,
508 struct vm_area_struct *vma, unsigned long start,
509 unsigned long end, pgprot_t newprot,
510 unsigned long cp_flags)
514 BUG_ON((cp_flags & MM_CP_UFFD_WP_ALL) == MM_CP_UFFD_WP_ALL);
516 if (is_vm_hugetlb_page(vma))
517 pages = hugetlb_change_protection(vma, start, end, newprot,
520 pages = change_protection_range(tlb, vma, start, end, newprot,
526 static int prot_none_pte_entry(pte_t *pte, unsigned long addr,
527 unsigned long next, struct mm_walk *walk)
529 return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ?
533 static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask,
534 unsigned long addr, unsigned long next,
535 struct mm_walk *walk)
537 return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ?
541 static int prot_none_test(unsigned long addr, unsigned long next,
542 struct mm_walk *walk)
547 static const struct mm_walk_ops prot_none_walk_ops = {
548 .pte_entry = prot_none_pte_entry,
549 .hugetlb_entry = prot_none_hugetlb_entry,
550 .test_walk = prot_none_test,
554 mprotect_fixup(struct mmu_gather *tlb, struct vm_area_struct *vma,
555 struct vm_area_struct **pprev, unsigned long start,
556 unsigned long end, unsigned long newflags)
558 struct mm_struct *mm = vma->vm_mm;
559 unsigned long oldflags = vma->vm_flags;
560 long nrpages = (end - start) >> PAGE_SHIFT;
561 unsigned long charged = 0;
562 bool try_change_writable;
566 if (newflags == oldflags) {
572 * Do PROT_NONE PFN permission checks here when we can still
573 * bail out without undoing a lot of state. This is a rather
574 * uncommon case, so doesn't need to be very optimized.
576 if (arch_has_pfn_modify_check() &&
577 (vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&
578 (newflags & VM_ACCESS_FLAGS) == 0) {
579 pgprot_t new_pgprot = vm_get_page_prot(newflags);
581 error = walk_page_range(current->mm, start, end,
582 &prot_none_walk_ops, &new_pgprot);
588 * If we make a private mapping writable we increase our commit;
589 * but (without finer accounting) cannot reduce our commit if we
590 * make it unwritable again. hugetlb mapping were accounted for
591 * even if read-only so there is no need to account for them here
593 if (newflags & VM_WRITE) {
594 /* Check space limits when area turns into data. */
595 if (!may_expand_vm(mm, newflags, nrpages) &&
596 may_expand_vm(mm, oldflags, nrpages))
598 if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB|
599 VM_SHARED|VM_NORESERVE))) {
601 if (security_vm_enough_memory_mm(mm, charged))
603 newflags |= VM_ACCOUNT;
608 * First try to merge with previous and/or next vma.
610 pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
611 *pprev = vma_merge(mm, *pprev, start, end, newflags,
612 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
613 vma->vm_userfaultfd_ctx, anon_vma_name(vma));
616 VM_WARN_ON((vma->vm_flags ^ newflags) & ~VM_SOFTDIRTY);
622 if (start != vma->vm_start) {
623 error = split_vma(mm, vma, start, 1);
628 if (end != vma->vm_end) {
629 error = split_vma(mm, vma, end, 0);
636 * vm_flags and vm_page_prot are protected by the mmap_lock
637 * held in write mode.
639 vma->vm_flags = newflags;
641 * We want to check manually if we can change individual PTEs writable
642 * if we can't do that automatically for all PTEs in a mapping. For
643 * private mappings, that's always the case when we have write
644 * permissions as we properly have to handle COW.
646 if (vma->vm_flags & VM_SHARED)
647 try_change_writable = vma_wants_writenotify(vma, vma->vm_page_prot);
649 try_change_writable = !!(vma->vm_flags & VM_WRITE);
650 vma_set_page_prot(vma);
652 change_protection(tlb, vma, start, end, vma->vm_page_prot,
653 try_change_writable ? MM_CP_TRY_CHANGE_WRITABLE : 0);
656 * Private VM_LOCKED VMA becoming writable: trigger COW to avoid major
659 if ((oldflags & (VM_WRITE | VM_SHARED | VM_LOCKED)) == VM_LOCKED &&
660 (newflags & VM_WRITE)) {
661 populate_vma_page_range(vma, start, end, NULL);
664 vm_stat_account(mm, oldflags, -nrpages);
665 vm_stat_account(mm, newflags, nrpages);
666 perf_event_mmap(vma);
670 vm_unacct_memory(charged);
675 * pkey==-1 when doing a legacy mprotect()
677 static int do_mprotect_pkey(unsigned long start, size_t len,
678 unsigned long prot, int pkey)
680 unsigned long nstart, end, tmp, reqprot;
681 struct vm_area_struct *vma, *prev;
683 const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
684 const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
686 struct mmu_gather tlb;
687 MA_STATE(mas, ¤t->mm->mm_mt, 0, 0);
689 start = untagged_addr(start);
691 prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
692 if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
695 if (start & ~PAGE_MASK)
699 len = PAGE_ALIGN(len);
703 if (!arch_validate_prot(prot, start))
708 if (mmap_write_lock_killable(current->mm))
712 * If userspace did not allocate the pkey, do not let
716 if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey))
719 mas_set(&mas, start);
720 vma = mas_find(&mas, ULONG_MAX);
725 if (unlikely(grows & PROT_GROWSDOWN)) {
726 if (vma->vm_start >= end)
728 start = vma->vm_start;
730 if (!(vma->vm_flags & VM_GROWSDOWN))
733 if (vma->vm_start > start)
735 if (unlikely(grows & PROT_GROWSUP)) {
738 if (!(vma->vm_flags & VM_GROWSUP))
743 if (start > vma->vm_start)
746 prev = mas_prev(&mas, 0);
748 tlb_gather_mmu(&tlb, current->mm);
749 for (nstart = start ; ; ) {
750 unsigned long mask_off_old_flags;
751 unsigned long newflags;
754 /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
756 /* Does the application expect PROT_READ to imply PROT_EXEC */
757 if (rier && (vma->vm_flags & VM_MAYEXEC))
761 * Each mprotect() call explicitly passes r/w/x permissions.
762 * If a permission is not passed to mprotect(), it must be
763 * cleared from the VMA.
765 mask_off_old_flags = VM_ACCESS_FLAGS | VM_FLAGS_CLEAR;
767 new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey);
768 newflags = calc_vm_prot_bits(prot, new_vma_pkey);
769 newflags |= (vma->vm_flags & ~mask_off_old_flags);
771 /* newflags >> 4 shift VM_MAY% in place of VM_% */
772 if ((newflags & ~(newflags >> 4)) & VM_ACCESS_FLAGS) {
777 /* Allow architectures to sanity-check the new flags */
778 if (!arch_validate_flags(newflags)) {
783 error = security_file_mprotect(vma, reqprot, prot);
791 if (vma->vm_ops && vma->vm_ops->mprotect) {
792 error = vma->vm_ops->mprotect(vma, nstart, tmp, newflags);
797 error = mprotect_fixup(&tlb, vma, &prev, nstart, tmp, newflags);
803 if (nstart < prev->vm_end)
804 nstart = prev->vm_end;
808 vma = find_vma(current->mm, prev->vm_end);
809 if (!vma || vma->vm_start != nstart) {
815 tlb_finish_mmu(&tlb);
817 mmap_write_unlock(current->mm);
821 SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
824 return do_mprotect_pkey(start, len, prot, -1);
827 #ifdef CONFIG_ARCH_HAS_PKEYS
829 SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len,
830 unsigned long, prot, int, pkey)
832 return do_mprotect_pkey(start, len, prot, pkey);
835 SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val)
840 /* No flags supported yet. */
843 /* check for unsupported init values */
844 if (init_val & ~PKEY_ACCESS_MASK)
847 mmap_write_lock(current->mm);
848 pkey = mm_pkey_alloc(current->mm);
854 ret = arch_set_user_pkey_access(current, pkey, init_val);
856 mm_pkey_free(current->mm, pkey);
861 mmap_write_unlock(current->mm);
865 SYSCALL_DEFINE1(pkey_free, int, pkey)
869 mmap_write_lock(current->mm);
870 ret = mm_pkey_free(current->mm, pkey);
871 mmap_write_unlock(current->mm);
874 * We could provide warnings or errors if any VMA still
875 * has the pkey set here.
880 #endif /* CONFIG_ARCH_HAS_PKEYS */