From: Liam R. Howlett Date: Thu, 28 Sep 2023 17:24:32 +0000 (-0400) Subject: mm/mempolicy: fix set_mempolicy_home_node() previous VMA pointer X-Git-Tag: microblaze-v6.8~234^2~18 X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=51f625377561e5b167da2db5aafb7ee268f691c5;p=linux-2.6-microblaze.git mm/mempolicy: fix set_mempolicy_home_node() previous VMA pointer 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: f4e9e0e69468 ("mm/mempolicy: fix use-after-free of VMA iterator") Signed-off-by: Liam R. Howlett Reported-by: Yikebaer Aizezi Closes: https://lore.kernel.org/linux-mm/CALcu4rbT+fMVNaO_F2izaCT+e7jzcAciFkOvk21HGJsmLcUuwQ@mail.gmail.com/ Reviewed-by: Lorenzo Stoakes Cc: Signed-off-by: Andrew Morton --- diff --git a/mm/mempolicy.c b/mm/mempolicy.c index f1b00d6ac7ee..29ebf1e7898c 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -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;