This is a note to let you know that I've just added the patch titled
md: fix an incorrect NULL check in md_reload_sb
to the 5.17-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
md-fix-an-incorrect-null-check-in-md_reload_sb.patch
and it can be found in the queue-5.17 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 64c54d9244a4efe9bc6e9c98e13c4bbb8bb39083 Mon Sep 17 00:00:00 2001
From: Xiaomeng Tong <xiam0nd.tong@xxxxxxxxx>
Date: Fri, 8 Apr 2022 16:47:15 +0800
Subject: md: fix an incorrect NULL check in md_reload_sb
From: Xiaomeng Tong <xiam0nd.tong@xxxxxxxxx>
commit 64c54d9244a4efe9bc6e9c98e13c4bbb8bb39083 upstream.
The bug is here:
if (!rdev || rdev->desc_nr != nr) {
The list iterator value 'rdev' will *always* be set and non-NULL
by rdev_for_each_rcu(), so it is incorrect to assume that the
iterator value will be NULL if the list is empty or no element
found (In fact, it will be a bogus pointer to an invalid struct
object containing the HEAD). Otherwise it will bypass the check
and lead to invalid memory access passing the check.
To fix the bug, use a new variable 'iter' as the list iterator,
while using the original variable 'pdev' as a dedicated pointer to
point to the found element.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 70bcecdb1534 ("md-cluster: Improve md_reload_sb to be less error prone")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@xxxxxxxxx>
Signed-off-by: Song Liu <song@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/md.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -9794,16 +9794,18 @@ static int read_rdev(struct mddev *mddev
void md_reload_sb(struct mddev *mddev, int nr)
{
- struct md_rdev *rdev;
+ struct md_rdev *rdev = NULL, *iter;
int err;
/* Find the rdev */
- rdev_for_each_rcu(rdev, mddev) {
- if (rdev->desc_nr == nr)
+ rdev_for_each_rcu(iter, mddev) {
+ if (iter->desc_nr == nr) {
+ rdev = iter;
break;
+ }
}
- if (!rdev || rdev->desc_nr != nr) {
+ if (!rdev) {
pr_warn("%s: %d Could not find rdev with nr %d\n", __func__, __LINE__, nr);
return;
}
Patches currently in stable-queue which might be from xiam0nd.tong@xxxxxxxxx are
queue-5.17/md-fix-an-incorrect-null-check-in-does_sb_need_changing.patch
queue-5.17/scsi-dc395x-fix-a-missing-check-on-list-iterator.patch
queue-5.17/drm-nouveau-clk-fix-an-incorrect-null-check-on-list-iterator.patch
queue-5.17/media-uvcvideo-fix-missing-check-to-determine-if-ele.patch
queue-5.17/md-fix-an-incorrect-null-check-in-md_reload_sb.patch
queue-5.17/drm-nouveau-kms-nv50-atom-fix-an-incorrect-null-check-on-list-iterator.patch
