[20:03] <webchat8> a RAID 5 mdadm array with a write journal has started segfaulting the kernel after upgrading 22.04 LTS to the latest 5.19.0-50 kernel.  this crash happens within a couple hours, and results in unclean shutdowns of arrays, file systems, and sometimes hangs the rebooting process as well requiring pressing the reset button on the machine.
[20:03] <webchat8> suspecting the write-through journal is at fault (because previously a write-back journal periodically hung the array and resulted in more unclean shutdowns), I tried changing the array back to use a bitmap consistency policy instead.  I have not been able to disable the write journal and moving the array back to using a bitmap, or even to resync.
[20:03] <webchat8> mdadm's manual suggests doing that is not well supported, but circumstantial evidence says removing a write journal may be done by failing then removing the journal device from the raid 5 array.  the procedure is not documented.  do you have any suggestions on how to proceed here?
[20:04] <sarnold> I think if it were me I'd try to reproduce the setup with VMs and test a bunch of the choices there, before doing anything on a filesystem that would be timeconsuming/expensive to restore from backups
[20:09] <webchat8> that's always a choice, the restore from backups route.  fortunately it's not that much data.  and of course multiple such backups exist.
[20:09] <webchat8> but what should I make of "mdadm segfaults the kernel"?
[20:17] <sarnold> webchat8: it'd be nice to get a bug report for that one :)
[21:21] <Yakov> having device /dev/ezcap -> video1, it seem to be busy, how to find processes related to the device?
[21:24] <tomreyn> lsof
[21:31] <Yakov> having device /dev/ezcap -> video1, it seem to be busy, how to find processes related to the device?
[21:32] <oerheks> lsof /dev/video1
[21:32] <oerheks> or ezcap ?
[21:37] <Yakov> it works for same namespaces, thank you, oerheks
[21:38] <Yakov> having some ghost commands, know PID
[21:38] <Yakov> how to kill?
[21:40] <oerheks> ps aux | grep Z   ##  then "kill PID" where PID is the process ID of the zombies process
[21:41] <oerheks> or if you know what application you started; pkill <application>
[21:42] <Yakov> COMMAND     PID      USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
[21:42] <Yakov> memcheck- 11082 supernova    6u   CHR   81,1      0t0  848 /dev/video1
[21:42] <Yakov> cant kill it