The quilt patch titled Subject: mmap: fix error paths with dup_anon_vma() has been removed from the -mm tree. Its filename was mmap-fix-error-paths-with-dup_anon_vma.patch
This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------ From: "Liam R. Howlett" Liam.Howlett@oracle.com Subject: mmap: fix error paths with dup_anon_vma() Date: Fri, 29 Sep 2023 14:30:40 -0400
When the calling function fails after the dup_anon_vma(), the duplication of the anon_vma is not being undone. Add the necessary unlink_anon_vma() call to the error paths that are missing them.
This issue showed up during inspection of the error path in vma_merge() for an unrelated vma iterator issue.
Users may experience increased memory usage, which may be problematic as the failure would likely be caused by a low memory situation.
Link: https://lkml.kernel.org/r/20230929183041.2835469-3-Liam.Howlett@oracle.com Fixes: d4af56c5c7c6 ("mm: start tracking VMAs with maple tree") Signed-off-by: Liam R. Howlett Liam.Howlett@oracle.com Reviewed-by: Lorenzo Stoakes lstoakes@gmail.com Acked-by: Vlastimil Babka vbabka@suse.cz Cc: Jann Horn jannh@google.com Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: Suren Baghdasaryan surenb@google.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
mm/mmap.c | 30 ++++++++++++++++++++++-------- 1 file changed, 22 insertions(+), 8 deletions(-)
--- a/mm/mmap.c~mmap-fix-error-paths-with-dup_anon_vma +++ a/mm/mmap.c @@ -583,11 +583,12 @@ again: * dup_anon_vma() - Helper function to duplicate anon_vma * @dst: The destination VMA * @src: The source VMA + * @dup: Pointer to the destination VMA when successful. * * Returns: 0 on success. */ static inline int dup_anon_vma(struct vm_area_struct *dst, - struct vm_area_struct *src) + struct vm_area_struct *src, struct vm_area_struct **dup) { /* * Easily overlooked: when mprotect shifts the boundary, make sure the @@ -595,9 +596,15 @@ static inline int dup_anon_vma(struct vm * anon pages imported. */ if (src->anon_vma && !dst->anon_vma) { + int ret; + vma_assert_write_locked(dst); dst->anon_vma = src->anon_vma; - return anon_vma_clone(dst, src); + ret = anon_vma_clone(dst, src); + if (ret) + return ret; + + *dup = dst; }
return 0; @@ -624,6 +631,7 @@ int vma_expand(struct vma_iterator *vmi, unsigned long start, unsigned long end, pgoff_t pgoff, struct vm_area_struct *next) { + struct vm_area_struct *anon_dup = NULL; bool remove_next = false; struct vma_prepare vp;
@@ -633,7 +641,7 @@ int vma_expand(struct vma_iterator *vmi,
remove_next = true; vma_start_write(next); - ret = dup_anon_vma(vma, next); + ret = dup_anon_vma(vma, next, &anon_dup); if (ret) return ret; } @@ -661,6 +669,8 @@ int vma_expand(struct vma_iterator *vmi, return 0;
nomem: + if (anon_dup) + unlink_anon_vmas(anon_dup); return -ENOMEM; }
@@ -860,6 +870,7 @@ struct vm_area_struct *vma_merge(struct { struct vm_area_struct *curr, *next, *res; struct vm_area_struct *vma, *adjust, *remove, *remove2; + struct vm_area_struct *anon_dup = NULL; struct vma_prepare vp; pgoff_t vma_pgoff; int err = 0; @@ -927,18 +938,18 @@ struct vm_area_struct *vma_merge(struct vma_start_write(next); remove = next; /* case 1 */ vma_end = next->vm_end; - err = dup_anon_vma(prev, next); + err = dup_anon_vma(prev, next, &anon_dup); if (curr) { /* case 6 */ vma_start_write(curr); remove = curr; remove2 = next; if (!next->anon_vma) - err = dup_anon_vma(prev, curr); + err = dup_anon_vma(prev, curr, &anon_dup); } } else if (merge_prev) { /* case 2 */ if (curr) { vma_start_write(curr); - err = dup_anon_vma(prev, curr); + err = dup_anon_vma(prev, curr, &anon_dup); if (end == curr->vm_end) { /* case 7 */ remove = curr; } else { /* case 5 */ @@ -954,7 +965,7 @@ struct vm_area_struct *vma_merge(struct vma_end = addr; adjust = next; adj_start = -(prev->vm_end - addr); - err = dup_anon_vma(next, prev); + err = dup_anon_vma(next, prev, &anon_dup); } else { /* * Note that cases 3 and 8 are the ONLY ones where prev @@ -968,7 +979,7 @@ struct vm_area_struct *vma_merge(struct vma_pgoff = curr->vm_pgoff; vma_start_write(curr); remove = curr; - err = dup_anon_vma(next, curr); + err = dup_anon_vma(next, curr, &anon_dup); } } } @@ -1018,6 +1029,9 @@ struct vm_area_struct *vma_merge(struct return res;
prealloc_fail: + if (anon_dup) + unlink_anon_vmas(anon_dup); + anon_vma_fail: vma_iter_set(vmi, addr); vma_iter_load(vmi); _
Patches currently in -mm which might be from Liam.Howlett@oracle.com are
mmap-add-clarifying-comment-to-vma_merge-code.patch radix-tree-test-suite-fix-allocation-calculation-in-kmem_cache_alloc_bulk.patch