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mm/mempolicy: fix set_mempolicy_home_node() previous VMA pointer

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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@oracle.com
Link: https://lore.kernel.org/linux-mm/CALcu4rbT+fMVNaO_F2izaCT+e7jzcAciFkOvk21HGJsmLcUuwQ@mail.gmail.com/
Fixes: f4e9e0e694 ("mm/mempolicy: fix use-after-free of VMA iterator")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Yikebaer Aizezi <yikebaer61@gmail.com>
Closes: https://lore.kernel.org/linux-mm/CALcu4rbT+fMVNaO_F2izaCT+e7jzcAciFkOvk21HGJsmLcUuwQ@mail.gmail.com/
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Liam R. Howlett 2023-09-28 13:24:32 -04:00 committed by Andrew Morton
parent 61e21cf2d2
commit 51f6253775
1 changed files with 3 additions and 1 deletions
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4
mm/mempolicy.c
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@ -1543,8 +1543,10 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
* 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;