FAILED: patch "[PATCH] mm/mempolicy: fix set_mempolicy_home_node() previous VMA" failed to apply to 6.1-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 51f625377561e5b167da2db5aafb7ee268f691c5
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023102704-surrogate-dole-2888@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 51f625377561e5b167da2db5aafb7ee268f691c5 Mon Sep 17 00:00:00 2001
From: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Date: Thu, 28 Sep 2023 13:24:32 -0400
Subject: [PATCH] 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 <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>

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;