From 4c6759967826b87f56c73e0f1deb7b76379ccd23 Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Mon, 27 Feb 2023 17:00:14 -0800 Subject: [PATCH] mm/mremap: fix dup_anon_vma() in vma_merge() case 4 In case 4, we are shrinking 'prev' (PPPP in the comment) and expanding 'mid' (NNNN). So we need to make sure 'mid' clones the anon_vma from 'prev', if it doesn't have any. After commit 0503ea8f5ba7 ("mm/mmap: remove __vma_adjust()") we can fail to do that due to wrong parameters for dup_anon_vma(). The call is a no-op because res == next, adjust == mid and mid == next. Fix it. Link: https://lkml.kernel.org/r/ad91d62b-37eb-4b73-707a-3c45c9e16256@suse.cz Fixes: 0503ea8f5ba7 ("mm/mmap: remove __vma_adjust()") Signed-off-by: Vlastimil Babka Reviewed-by: Liam R. Howlett Signed-off-by: Andrew Morton --- mm/mmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/mmap.c b/mm/mmap.c index 20f21f0949dd..740b54be3ed4 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -973,7 +973,7 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, vma_end = addr; adjust = mid; adj_next = -(vma->vm_end - addr); - err = dup_anon_vma(res, adjust); + err = dup_anon_vma(adjust, prev); } else { vma = next; /* case 3 */ vma_start = addr; -- 2.39.5