From: Vlastimil Babka <vbabka@suse.cz>
To: linux-mm@kvack.org, "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: linux-kernel@vger.kernel.org, patches@lists.linux.dev,
maple-tree@lists.infradead.org, Vlastimil Babka <vbabka@suse.cz>
Subject: [RFC 01/11] mm/mremap: fix dup_anon_vma() in vma_merge() case 4
Date: Fri, 24 Feb 2023 11:00:12 +0100 [thread overview]
Message-ID: <20230224100022.11268-2-vbabka@suse.cz> (raw)
In-Reply-To: <20230224100022.11268-1-vbabka@suse.cz>
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.
Fixes: 0503ea8f5ba7 ("mm/mmap: remove __vma_adjust()")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
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;
--
2.39.2
next prev parent reply other threads:[~2023-02-24 10:00 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-24 10:00 [RFC 00/11] cleanup vma_merge and improve mergeability tests Vlastimil Babka
2023-02-24 10:00 ` Vlastimil Babka [this message]
2023-02-24 10:00 ` [RFC 02/11] mm/mmap/vma_merge: use only primary pointers for preparing merge Vlastimil Babka
2023-02-24 10:00 ` [RFC 03/11] mm/mmap/vma_merge: use the proper vma pointer in case 3 Vlastimil Babka
2023-02-24 10:00 ` [RFC 04/11] mm/mmap/vma_merge: use the proper vma pointers in cases 1 and 6 Vlastimil Babka
2023-02-24 10:00 ` [RFC 05/11] mm/mmap/vma_merge: use the proper vma pointer in case 4 Vlastimil Babka
2023-02-24 10:00 ` [RFC 06/11] mm/mmap/vma_merge: initialize mid and next in natural order Vlastimil Babka
2023-02-24 10:00 ` [RFC 07/11] mm/mmap/vma_merge: set mid to NULL if not applicable Vlastimil Babka
2023-02-24 10:00 ` [RFC 08/11] mm/mmap/vma_merge: rename adj_next to adj_start Vlastimil Babka
2023-02-24 10:00 ` [RFC 09/11] mm/mmap/vma_merge: convert mergeability checks to return bool Vlastimil Babka
2023-02-24 10:00 ` [RFC 10/11] mm/mmap: start distinguishing if vma can be removed in mergeability test Vlastimil Babka
2023-02-24 10:00 ` [RFC 11/11] mm/mremap: simplify vma expansion again Vlastimil Babka
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