[PATCH 0/1][SRU][M] Infiniate systemd loop when power off

[AceLan Kao]

From: "Chia-Lin Kao (AceLan)" <acelan.kao at canonical.com>

BugLink: https://bugs.launchpad.net/bugs/2036184

[Impact]
The system with multiple MD RAIDs sometimes hangs while rebooting, that's
because of the systemd can't stop and close the MD disk.

[Fix]
This commit fixes the issue, and this issue has been introduced by
12a6caf27324 ("md: only delete entries from all_mddevs when the disk is freed")
after v6.0

https://patchwork.kernel.org/project/linux-raid/patch/20230914152416.10819-1-mariusz.tkaczyk@linux.intel.com/

[Test case]
1. Reboot the system with multiple MD RAIDs at least 10 times.
2. Make sure the system can reboot successfully every time.
3. You should not see error messages like below.

[ 205.360738] systemd-shutdown[1]: Stopping MD devices.
[ 205.366384] systemd-shutdown[1]: sd-device-enumerator: Scan all dirs
[ 205.373327] systemd-shutdown[1]: sd-device-enumerator: Scanning /sys/bus
[ 205.380427] systemd-shutdown[1]: sd-device-enumerator: Scanning /sys/class
[ 205.388257] systemd-shutdown[1]: Stopping MD /dev/md127 (9:127).
[ 205.394880] systemd-shutdown[1]: Failed to sync MD block device /dev/md127, ignoring: Input/output error
[ 205.404975] md: md127 stopped.
[ 205.470491] systemd-shutdown[1]: Stopping MD /dev/md126 (9:126).
[ 205.770179] md: md126: resync interrupted.
[ 205.776258] md126: detected capacity change from 1900396544 to 0
[ 205.783349] md: md126 stopped.
[ 205.862258] systemd-shutdown[1]: Stopping MD /dev/md125 (9:125).
[ 205.862435] md: md126 stopped.
[ 205.868376] systemd-shutdown[1]: Failed to sync MD block device /dev/md125, ignoring: Input/output error
[ 205.872845] block device autoloading is deprecated and will be removed.
[ 205.880955] md: md125 stopped.
[ 205.934349] systemd-shutdown[1]: Stopping MD /dev/md124p2 (259:7).
[ 205.947707] systemd-shutdown[1]: Could not stop MD /dev/md124p2: Device or resource busy
[ 205.957004] systemd-shutdown[1]: Stopping MD /dev/md124p1 (259:6).
[ 205.964177] systemd-shutdown[1]: Could not stop MD /dev/md124p1: Device or resource busy
[ 205.973155] systemd-shutdown[1]: Stopping MD /dev/md124 (9:124).
[ 205.979789] systemd-shutdown[1]: Could not stop MD /dev/md124: Device or resource busy
[ 205.988475] systemd-shutdown[1]: Not all MD devices stopped, 4 left.

[Where problems could occur]
It fixes the data race issue, should not introduce any regression.

Mariusz Tkaczyk (1):
  UBUNTU: SAUCE: md: do not _put wrong device in md_seq_next

 drivers/md/md.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
2.34.1