The quilt patch titled Subject: mm: correctly reference merged VMA has been removed from the -mm tree. Its filename was mm-correctly-reference-merged-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: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx> Subject: mm: correctly reference merged VMA Date: Fri, 6 Dec 2024 21:52:29 +0000 On second merge attempt on mmap() we incorrectly discard the possibly merged VMA, resulting in a possible use-after-free (and most certainly a reference to the wrong VMA) in this instance in the subsequent __mmap_complete() invocation. Correct this mistake by reassigning vma correctly if a merge succeeds in this case. Link: https://lkml.kernel.org/r/20241206215229.244413-1-lorenzo.stoakes@xxxxxxxxxx Fixes: 5ac87a885aec ("mm: defer second attempt at merge on mmap()") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx> Suggested-by: Jann Horn <jannh@xxxxxxxxxx> Reported-by: syzbot+91cf8da9401355f946c3@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://lore.kernel.org/all/67536a25.050a0220.a30f1.0149.GAE@xxxxxxxxxx/ Reviewed-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vma.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/mm/vma.c~mm-correctly-reference-merged-vma +++ a/mm/vma.c @@ -2460,10 +2460,13 @@ unsigned long __mmap_region(struct file /* If flags changed, we might be able to merge, so try again. */ if (map.retry_merge) { + struct vm_area_struct *merged; VMG_MMAP_STATE(vmg, &map, vma); vma_iter_config(map.vmi, map.addr, map.end); - vma_merge_existing_range(&vmg); + merged = vma_merge_existing_range(&vmg); + if (merged) + vma = merged; } __mmap_complete(&map, vma); _ Patches currently in -mm which might be from lorenzo.stoakes@xxxxxxxxxx are mm-reinstate-ability-to-map-write-sealed-memfd-mappings-read-only.patch selftests-memfd-add-test-for-mapping-write-sealed-memfd-read-only.patch mm-vma-move-brk-internals-to-mm-vmac.patch mm-vma-move-brk-internals-to-mm-vmac-fix.patch mm-vma-move-unmapped_area-internals-to-mm-vmac.patch mm-abstract-get_arg_page-stack-expansion-and-mmap-read-lock.patch mm-vma-move-stack-expansion-logic-to-mm-vmac.patch mm-vma-move-__vm_munmap-to-mm-vmac.patch selftests-mm-add-fork-cow-guard-page-test.patch mm-enforce-__must_check-on-vma-merge-and-split.patch mm-perform-all-memfd-seal-checks-in-a-single-place.patch mm-perform-all-memfd-seal-checks-in-a-single-place-fix.patch maintainers-update-memory-mapping-section.patch mm-assert-mmap-write-lock-held-on-do_mmap-mmap_region.patch mm-add-comments-to-do_mmap-mmap_region-and-vm_mmap.patch tools-testing-add-simple-__mmap_region-userland-test.patch