The patch titled
Subject: mm/mempolicy: fix mbind_range() arguments to vma_merge()
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-mempolicy-fix-mbind_range-arguments-to-vma_merge.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mempolicy-fix-mbind_range-arguments-to-vma_merge.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Liam Howlett <liam.howlett@xxxxxxxxxx>
Subject: mm/mempolicy: fix mbind_range() arguments to vma_merge()
Date: Sat, 15 Oct 2022 02:12:33 +0000
Fuzzing produced an invalid argument to vma_merge() which was caught
by the newly added verification of the number of VMAs being removed on
process exit. Analyzing the failure eventually resulted in finding an
issue with the search of a VMA that started at address 0, which caused
an underflow and thus the loss of many VMAs being tracked in the tree.
Fix the underflow by changing the search of the maple tree to use the
start address directly.
Link: https://lkml.kernel.org/r/20221015021135.2816178-1-Liam.Howlett@xxxxxxxxxx
Fixes: 66850be55e8e ("mm/mempolicy: use vma iterator & maple state instead of vma linked list")
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
Link: https://lore.kernel.org/r/202210052318.5ad10912-oliver.sang@xxxxxxxxx
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mempolicy.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
--- a/mm/mempolicy.c~mm-mempolicy-fix-mbind_range-arguments-to-vma_merge
+++ a/mm/mempolicy.c
@@ -787,17 +787,22 @@ static int vma_replace_policy(struct vm_
static int mbind_range(struct mm_struct *mm, unsigned long start,
unsigned long end, struct mempolicy *new_pol)
{
- MA_STATE(mas, &mm->mm_mt, start - 1, start - 1);
+ MA_STATE(mas, &mm->mm_mt, start, start);
struct vm_area_struct *prev;
struct vm_area_struct *vma;
int err = 0;
pgoff_t pgoff;
- prev = mas_find_rev(&mas, 0);
- if (prev && (start < prev->vm_end))
- vma = prev;
- else
- vma = mas_next(&mas, end - 1);
+ prev = mas_prev(&mas, 0);
+ if (unlikely(!prev))
+ mas_set(&mas, start);
+
+ vma = mas_find(&mas, end - 1);
+ if (WARN_ON(!vma))
+ return 0;
+
+ if (start > vma->vm_start)
+ prev = vma;
for (; vma; vma = mas_next(&mas, end - 1)) {
unsigned long vmstart = max(start, vma->vm_start);
_
Patches currently in -mm which might be from liam.howlett@xxxxxxxxxx are
mm-mempolicy-fix-mbind_range-arguments-to-vma_merge.patch
