The patch titled
Subject: mm/mempolicy: fix set_mempolicy_home_node() previous VMA pointer
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-mempolicy-fix-set_mempolicy_home_node-previous-vma-pointer.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-set_mempolicy_home_node-previous-vma-pointer.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 R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Subject: mm/mempolicy: fix set_mempolicy_home_node() previous VMA pointer
Date: Thu, 28 Sep 2023 13:24:32 -0400
The two users of mbind_range() are expecting that mbind_range() will
update the pointer to the previous VMA, or return an error. However,
set_mempolicy_home_node() does not call mbind_range() if there is no VMA
policy. The fix is to update the pointer to the previous VMA prior to
continuing iterating the VMAs when there is no policy.
Users may experience a WARN_ON() during VMA policy updates when updating
a range of VMAs on the home node.
Link: https://lkml.kernel.org/r/20230928172432.2246534-1-Liam.Howlett@xxxxxxxxxx
Link: https://lore.kernel.org/linux-mm/CALcu4rbT+fMVNaO_F2izaCT+e7jzcAciFkOvk21HGJsmLcUuwQ@xxxxxxxxxxxxxx/
Fixes: f4e9e0e69468 ("mm/mempolicy: fix use-after-free of VMA iterator")
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reported-by: Yikebaer Aizezi <yikebaer61@xxxxxxxxx>
Closes: https://lore.kernel.org/linux-mm/CALcu4rbT+fMVNaO_F2izaCT+e7jzcAciFkOvk21HGJsmLcUuwQ@xxxxxxxxxxxxxx/
Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mempolicy.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/mm/mempolicy.c~mm-mempolicy-fix-set_mempolicy_home_node-previous-vma-pointer
+++ a/mm/mempolicy.c
@@ -1543,8 +1543,10 @@ SYSCALL_DEFINE4(set_mempolicy_home_node,
* the home node for vmas we already updated before.
*/
old = vma_policy(vma);
- if (!old)
+ if (!old) {
+ prev = vma;
continue;
+ }
if (old->mode != MPOL_BIND && old->mode != MPOL_PREFERRED_MANY) {
err = -EOPNOTSUPP;
break;
_
Patches currently in -mm which might be from Liam.Howlett@xxxxxxxxxx are
maple_tree-add-mas_active-to-detect-in-tree-walks.patch
maple_tree-add-mas_underflow-and-mas_overflow-states.patch
mmap-fix-vma_iterator-in-error-path-of-vma_merge.patch
mmap-fix-error-paths-with-dup_anon_vma.patch
mm-mempolicy-fix-set_mempolicy_home_node-previous-vma-pointer.patch
mmap-add-clarifying-comment-to-vma_merge-code.patch
