Re: Infiniate systemd loop when power off the machine with multiple MD RAIDs

[Guoqing Jiang <guoqing.jiang@linux.dev>]

On 8/18/23 16:16, Mariusz Tkaczyk wrote:
> On Wed, 16 Aug 2023 16:37:26 +0700
> Bagas Sanjaya<bagasdotme@gmail.com>  wrote:
>
>> Hi,
>>
>> I notice a regression report on Bugzilla [1]. Quoting from it:
>>
>>> It needs to build at least 2 different RAIDs(eg. RAID0 and RAID10, RAID5
>>> and RAID10) and then you will see below error repeatly(need to use serial
>>> console to see it)
>>>
>>> [ 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.
>> See Bugzilla for the full thread and attached full journalctl log.
>>
>> Anyway, I'm adding this regression to be tracked by regzbot:
>>
>> #regzbot introduced: 12a6caf273240a
>> https://bugzilla.kernel.org/show_bug.cgi?id=217798  #regzbot title: systemd
>> shutdown hang on machine with different RAID levels
>>
>> Thanks.
>>
>> [1]:https://bugzilla.kernel.org/show_bug.cgi?id=217798
>>
> Hello,
> The issue is reproducible with IMSM metadata too, around 20% of reboot hangs. I
> will try to raise the priority in the bug because it is valid high- the
> base functionality of the system is affected.

Since it it reproducible from your side, is it possible to turn the 
reproduce steps into a test case
given the importance?

I guess If all arrays are set with MD_DELETED flag, then reboot might 
hang, not sure whether
below (maybe need to flush wq as well  before list_del) helps or not, 
just FYI.

@@ -9566,8 +9566,10 @@ static int md_notify_reboot(struct notifier_block 
*this,

         spin_lock(&all_mddevs_lock);
         list_for_each_entry_safe(mddev, n, &all_mddevs, all_mddevs) {
-               if (!mddev_get(mddev))
+               if (!mddev_get(mddev)) {
+                       list_del(&mddev->all_mddevs);
                         continue;
+               }

Thanks,
Guoqing