This is a note to let you know that I've just added the patch titled
mm/mmap: Fix extra maple tree write
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-mmap-fix-extra-maple-tree-write.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From Liam.Howlett@xxxxxxxxxx Sun Jul 16 17:02:51 2023
From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Date: Thu, 6 Jul 2023 14:51:35 -0400
Subject: mm/mmap: Fix extra maple tree write
To: linux-kernel@xxxxxxxxxxxxxxx
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>, "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>, John Hsu <John.Hsu@xxxxxxxxxxxx>, stable@xxxxxxxxxxxxxxx, linux-mm@xxxxxxxxx
Message-ID: <20230706185135.2235532-1-Liam.Howlett@xxxxxxxxxx>
From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
based on commit 0503ea8f5ba73eb3ab13a81c1eefbaf51405385a upstream.
This was inadvertently fixed during the removal of __vma_adjust().
When __vma_adjust() is adjusting next with a negative value (pushing
vma->vm_end lower), there would be two writes to the maple tree. The
first write is unnecessary and uses all allocated nodes in the maple
state. The second write is necessary but will need to allocate nodes
since the first write has used the allocated nodes. This may be a
problem as it may not be safe to allocate at this time, such as a low
memory situation. Fix the issue by avoiding the first write and only
write the adjusted "next" VMA.
Reported-by: John Hsu <John.Hsu@xxxxxxxxxxxx>
Link: https://lore.kernel.org/lkml/9cb8c599b1d7f9c1c300d1a334d5eb70ec4d7357.camel@xxxxxxxxxxxx/
Cc: stable@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index b8af52db3bbe..bb2e0ff0ef61 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -767,7 +767,8 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
}
if (end != vma->vm_end) {
if (vma->vm_end > end) {
- if (!insert || (insert->vm_start != end)) {
+ if ((vma->vm_end + adjust_next != end) &&
+ (!insert || (insert->vm_start != end))) {
vma_mas_szero(&mas, end, vma->vm_end);
mas_reset(&mas);
VM_WARN_ON(insert &&
--
2.39.2
Patches currently in stable-queue which might be from Liam.Howlett@xxxxxxxxxx are
queue-5.4/mm-mmap-fix-extra-maple-tree-write.patch
