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author | Liam R. Howlett <Liam.Howlett@oracle.com> | 2023-06-17 20:47:08 -0400 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-07-01 13:16:22 +0200 |
commit | a149174ff8bbdd8d5a0a591feaa3668ea4f43387 (patch) | |
tree | a647f9f1ad80e99661a95c13f15255e5105e7425 | |
parent | a1c449d00ff8ce2c5fcea5f755df682d1f6bc2ef (diff) | |
download | linux-stable-a149174ff8bbdd8d5a0a591feaa3668ea4f43387.tar.gz linux-stable-a149174ff8bbdd8d5a0a591feaa3668ea4f43387.tar.bz2 linux-stable-a149174ff8bbdd8d5a0a591feaa3668ea4f43387.zip |
mm/mmap: Fix error path in do_vmi_align_munmap()
commit 606c812eb1d5b5fb0dd9e330ca94b52d7c227830 upstream
The error unrolling was leaving the VMAs detached in many cases and
leaving the locked_vm statistic altered, and skipping the unrolling
entirely in the case of the vma tree write failing.
Fix the error path by re-attaching the detached VMAs and adding the
necessary goto for the failed vma tree write, and fix the locked_vm
statistic by only updating after the vma tree write succeeds.
Fixes: 763ecb035029 ("mm: remove the vma linked list")
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ dwmw2: Strictly, the original patch wasn't *re-attaching* the
detached VMAs. They *were* still attached but just had
the 'detached' flag set, which is an optimisation. Which
doesn't exist in 6.3, so drop that. Also drop the call
to vma_start_write() which came in with the per-VMA
locking in 6.4. ]
[ dwmw2 (6.1): It's do_mas_align_munmap() here. And has two call
sites for the now-removed munmap_sidetree() function.
Inline them both rather then trying to backport various
dependencies with potentially subtle interactions. ]
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | mm/mmap.c | 33 |
1 files changed, 14 insertions, 19 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 14ca259189b7..d82a95956def 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2311,19 +2311,6 @@ int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, return __split_vma(mm, vma, addr, new_below); } -static inline int munmap_sidetree(struct vm_area_struct *vma, - struct ma_state *mas_detach) -{ - mas_set_range(mas_detach, vma->vm_start, vma->vm_end - 1); - if (mas_store_gfp(mas_detach, vma, GFP_KERNEL)) - return -ENOMEM; - - if (vma->vm_flags & VM_LOCKED) - vma->vm_mm->locked_vm -= vma_pages(vma); - - return 0; -} - /* * do_mas_align_munmap() - munmap the aligned region from @start to @end. * @mas: The maple_state, ideally set up to alter the correct tree location. @@ -2345,6 +2332,7 @@ do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma, struct maple_tree mt_detach; int count = 0; int error = -ENOMEM; + unsigned long locked_vm = 0; MA_STATE(mas_detach, &mt_detach, 0, 0); mt_init_flags(&mt_detach, mas->tree->ma_flags & MT_FLAGS_LOCK_MASK); mt_set_external_lock(&mt_detach, &mm->mmap_lock); @@ -2403,18 +2391,23 @@ do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma, mas_set(mas, end); split = mas_prev(mas, 0); - error = munmap_sidetree(split, &mas_detach); + mas_set_range(&mas_detach, split->vm_start, split->vm_end - 1); + error = mas_store_gfp(&mas_detach, split, GFP_KERNEL); if (error) - goto munmap_sidetree_failed; + goto munmap_gather_failed; + if (next->vm_flags & VM_LOCKED) + locked_vm += vma_pages(split); count++; if (vma == next) vma = split; break; } - error = munmap_sidetree(next, &mas_detach); - if (error) - goto munmap_sidetree_failed; + mas_set_range(&mas_detach, next->vm_start, next->vm_end - 1); + if (mas_store_gfp(&mas_detach, next, GFP_KERNEL)) + goto munmap_gather_failed; + if (next->vm_flags & VM_LOCKED) + locked_vm += vma_pages(next); count++; #ifdef CONFIG_DEBUG_VM_MAPLE_TREE @@ -2464,6 +2457,8 @@ do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma, } #endif mas_store_prealloc(mas, NULL); + + mm->locked_vm -= locked_vm; mm->map_count -= count; /* * Do not downgrade mmap_lock if we are next to VM_GROWSDOWN or @@ -2490,7 +2485,7 @@ do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma, return downgrade ? 1 : 0; userfaultfd_error: -munmap_sidetree_failed: +munmap_gather_failed: end_split_failed: __mt_destroy(&mt_detach); start_split_failed: |