The patch below does not apply to the 4.4-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@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From f7c7a2f9a23e5b6e0f5251f29648d0238bb7757e Mon Sep 17 00:00:00 2001
From: Heming Zhao <heming.zhao@xxxxxxxx>
Date: Thu, 8 Apr 2021 15:44:15 +0800
Subject: [PATCH] md-cluster: fix use-after-free issue when removing rdev
md_kick_rdev_from_array will remove rdev, so we should
use rdev_for_each_safe to search list.
How to trigger:
env: Two nodes on kvm-qemu x86_64 VMs (2C2G with 2 iscsi luns).
```
node2=192.168.0.3
for i in {1..20}; do
echo ==== $i `date` ====;
mdadm -Ss && ssh ${node2} "mdadm -Ss"
wipefs -a /dev/sda /dev/sdb
mdadm -CR /dev/md0 -b clustered -e 1.2 -n 2 -l 1 /dev/sda \
/dev/sdb --assume-clean
ssh ${node2} "mdadm -A /dev/md0 /dev/sda /dev/sdb"
mdadm --wait /dev/md0
ssh ${node2} "mdadm --wait /dev/md0"
mdadm --manage /dev/md0 --fail /dev/sda --remove /dev/sda
sleep 1
done
```
Crash stack:
```
stack segment: 0000 [#1] SMP
... ...
RIP: 0010:md_check_recovery+0x1e8/0x570 [md_mod]
... ...
RSP: 0018:ffffb149807a7d68 EFLAGS: 00010207
RAX: 0000000000000000 RBX: ffff9d494c180800 RCX: ffff9d490fc01e50
RDX: fffff047c0ed8308 RSI: 0000000000000246 RDI: 0000000000000246
RBP: 6b6b6b6b6b6b6b6b R08: ffff9d490fc01e40 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
R13: ffff9d494c180818 R14: ffff9d493399ef38 R15: ffff9d4933a1d800
FS: 0000000000000000(0000) GS:ffff9d494f700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe68cab9010 CR3: 000000004c6be001 CR4: 00000000003706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
raid1d+0x5c/0xd40 [raid1]
? finish_task_switch+0x75/0x2a0
? lock_timer_base+0x67/0x80
? try_to_del_timer_sync+0x4d/0x80
? del_timer_sync+0x41/0x50
? schedule_timeout+0x254/0x2d0
? md_start_sync+0xe0/0xe0 [md_mod]
? md_thread+0x127/0x160 [md_mod]
md_thread+0x127/0x160 [md_mod]
? wait_woken+0x80/0x80
kthread+0x10d/0x130
? kthread_park+0xa0/0xa0
ret_from_fork+0x1f/0x40
```
Fixes: dbb64f8635f5d ("md-cluster: Fix adding of new disk with new reload code")
Fixes: 659b254fa7392 ("md-cluster: remove a disk asynchronously from cluster environment")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Gang He <ghe@xxxxxxxx>
Signed-off-by: Heming Zhao <heming.zhao@xxxxxxxx>
Signed-off-by: Song Liu <song@xxxxxxxxxx>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index af9bdb907b2b..49f897fbb89b 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -9289,11 +9289,11 @@ void md_check_recovery(struct mddev *mddev)
}
if (mddev_is_clustered(mddev)) {
- struct md_rdev *rdev;
+ struct md_rdev *rdev, *tmp;
/* kick the device if another node issued a
* remove disk.
*/
- rdev_for_each(rdev, mddev) {
+ rdev_for_each_safe(rdev, tmp, mddev) {
if (test_and_clear_bit(ClusterRemove, &rdev->flags) &&
rdev->raid_disk < 0)
md_kick_rdev_from_array(rdev);
@@ -9607,7 +9607,7 @@ static int __init md_init(void)
static void check_sb_changes(struct mddev *mddev, struct md_rdev *rdev)
{
struct mdp_superblock_1 *sb = page_address(rdev->sb_page);
- struct md_rdev *rdev2;
+ struct md_rdev *rdev2, *tmp;
int role, ret;
char b[BDEVNAME_SIZE];
@@ -9624,7 +9624,7 @@ static void check_sb_changes(struct mddev *mddev, struct md_rdev *rdev)
}
/* Check for change of roles in the active devices */
- rdev_for_each(rdev2, mddev) {
+ rdev_for_each_safe(rdev2, tmp, mddev) {
if (test_bit(Faulty, &rdev2->flags))
continue;
