From: Vlastimil Babka Date: Thu, 9 Mar 2023 11:12:51 +0000 (+0100) Subject: mm/mmap/vma_merge: use the proper vma pointers in cases 1 and 6 X-Git-Tag: v6.4-rc1~103^2~253 X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=5ff783f15176e85323e9d9349fefcd4de6e435bb;p=tomoyo%2Ftomoyo-test1.git mm/mmap/vma_merge: use the proper vma pointers in cases 1 and 6 Case 1 is now shown in the comment as next vma being merged with prev, so use 'next' instead of 'mid'. In case 1 they both point to the same vma. As a consequence, in case 6, the dup_anon_vma() is now tried first on 'next' and then on 'mid', before it was the opposite order. This is not a functional change, as those two vma's cannnot have a different anon_vma, as that would have prevented the merging in the first place. Link: https://lkml.kernel.org/r/20230309111258.24079-4-vbabka@suse.cz Signed-off-by: Vlastimil Babka Reviewed-by: Lorenzo Stoakes Reviewed-by: Liam R. Howlett Cc: Matthew Wilcox (Oracle) Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton --- diff --git a/mm/mmap.c b/mm/mmap.c index be8338318cfb..d1352a653df5 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -605,7 +605,7 @@ again: /* * In mprotect's case 6 (see comments on vma_merge), - * we must remove the one after next as well. + * we are removing both mid and next vmas */ if (vp->remove2) { vp->remove = vp->remove2; @@ -948,13 +948,14 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, /* Can we merge both the predecessor and the successor? */ if (merge_prev && merge_next && is_mergeable_anon_vma(prev->anon_vma, next->anon_vma, NULL)) { - remove = mid; /* case 1 */ + remove = next; /* case 1 */ vma_end = next->vm_end; - err = dup_anon_vma(prev, mid); + err = dup_anon_vma(prev, next); if (mid != next) { /* case 6 */ + remove = mid; remove2 = next; - if (!mid->anon_vma) - err = dup_anon_vma(prev, next); + if (!next->anon_vma) + err = dup_anon_vma(prev, mid); } } else if (merge_prev) { err = 0; /* case 2 */