On Wed, Jun 17, 2020 at 5:53 AM Michal Soltys <msoltyspl@xxxxxxxxx> wrote:
>
> On 6/17/20 2:48 AM, Song Liu wrote:
> > On Tue, Jun 9, 2020 at 2:51 PM Michal Soltys <msoltyspl@xxxxxxxxx> wrote:
> >>
> >> On 20/06/09 20:36, Song Liu wrote:
> >>> On Tue, Jun 9, 2020 at 2:36 AM Michal Soltys <msoltyspl@xxxxxxxxx> wrote:
> >>>>
> >>>> On 6/5/20 2:26 PM, Michal Soltys wrote:
> >>>>> On 6/4/20 12:07 AM, Song Liu wrote:
> >>>>>>
> >>>>>> The hang happens at expected place.
> >>>>>>
> >>>>>>> [Jun 3 09:02] INFO: task mdadm:2858 blocked for more than 120 seconds.
> >>>>>>> [ +0.060545] Tainted: G E
> >>>>>>> 5.4.19-msl-00001-gbf39596faf12 #2
> >>>>>>> [ +0.062932] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
> >>>>>>> disables this message.
> >>>>>>
> >>>>>> Could you please try disable the timeout message with
> >>>>>>
> >>>>>> echo 0 > /proc/sys/kernel/hung_task_timeout_secs
> >>>>>>
> >>>>>> And during this wait (after message
> >>>>>> "r5c_recovery_flush_data_only_stripes before wait_event"),
> >>>>>> checks whether the raid disks (not the journal disk) are taking IOs
> >>>>>> (using tools like iostat).
> >>>>>>
> >>>>>
> >>>>> No activity on component drives.
> >>>>
> >>>> To expand on that - while there is no i/o activity whatsoever at the component drives (as well as journal), the cpu is of course still fully loaded (5 days so far):
> >>>>
> >>>> UID PID PPID C SZ RSS PSR STIME TTY TIME CMD
> >>>> root 8129 6755 15 740 1904 10 Jun04 pts/2 17:42:34 mdadm -A /dev/md/r5_big /dev/md/r1_journal_big /dev/sdj1 /dev/sdi1 /dev/sdg1 /dev/sdh1
> >>>> root 8147 2 84 0 0 30 Jun04 ? 4-02:09:47 [md124_raid5]
> >>>
> >>> I guess the md thread stuck at some stripe. Does the kernel have
> >>> CONFIG_DYNAMIC_DEBUG enabled? If so, could you please try enable some pr_debug()
> >>> in function handle_stripe()?
> >>>
> >>> Thanks,
> >>> Song
> >>>
> >>
> >> Massive spam in dmesg with messages like these:
> >>
> >> [464836.603033] handling stripe 1551540328, state=0x41 cnt=1, pd_idx=3,
> >> qd_idx=-1
> >> , check:0, reconstruct:0
> >> <cut>
> >>
> >
> > I am really sorry for the delay. A few questions:
> >
>
> No worries.
>
> > 1. There are two pr_debug() calls in handle_stripe():
> > pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
> > pr_debug("locked=%d uptodate=%d to_read=%d"
> >
> > Did you enable all of them? Or only the first one?
>
> I enabled all of them (I think), to be precise:
>
> echo -n 'func handle_stripe +p' >/sys/kernel/debug/dynamic_debug/control
>
> Haven't seen any `locked` lines though.
That's a little weird, and probably explains why we stuck. Could you
please try the attached patch?
Thanks,
Song
Attachment:
0001-Debug-raid5-recovery-hang.patch
Description: Binary data
