6.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> commit 51f625377561e5b167da2db5aafb7ee268f691c5 upstream. 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/ Reviewed-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- mm/mempolicy.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/mm/mempolicy.c +++ b/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;
