Re: sync-Regression in 2.6.28.2?

From: Nick Piggin
Date: Mon Feb 02 2009 - 20:09:59 EST


On Wednesday 28 January 2009 08:09:10 Federico Cuello wrote:
> Ralf Hildebrandt escribiÃ:
> > I recently installed 2.6.28.2 on our postfix/dovecot-based
> > mailboxserver. Previously, 2.6.28 and 2.6.28.1 have been running there
> > without a hitch.
> >
> > Now with 2.6.28.2 I had two major lockups: All writes to the users'
> > Maildirs (on ext4) would stall, the load would rise, "sync" would never
> > return.
> >
> > I had to "reboot -f -n" to get the machine back. All hanging processes
> > were unkillable, even with kill -9.
> > [...]
>
> The same is happening to me, but I have some logs taken with sysrq.
>
> Here is my vmstat output:
>
> procs -----------memory---------- ---swap-- -----io---- -system--
> ----cpu----
> r b swpd free buff cache si so bi bo in cs us sy
> id wa
> 0 2 99028 46536 26356 1569400 0 0 0 0 1400 437 0
> 3 0 96
> 0 2 99028 46536 26356 1569400 0 0 0 0 1344 355 0
> 6 0 94
> 0 2 99028 46536 26356 1569400 0 0 0 0 1373 387 0
> 0 0 100
> 0 2 99028 46536 26364 1569400 0 0 0 12 1403 384 1
> 0 0 99
> 0 2 99028 46536 26364 1569400 0 0 0 0 1370 378 0
> 0 0 100
> 0 2 99028 46536 26364 1569400 0 0 0 0 1351 346 0
> 0 0 100
> 0 2 99028 46536 26364 1569400 0 0 0 0 1395 412 0
> 0 0 100
> 0 2 99028 46536 26364 1569400 0 0 0 0 1349 332 0
> 0 0 100
> 0 2 99028 46536 26368 1569400 0 0 4 0 1407 387 0
> 0 0 100
>
> Notice the 100% iowait.
>
> I also managed to reproduce it doing a rsync from one partition to a USB
> drive. After the lockup I can't read any file from the source partition,
> but the other partitions can be accessed normally.

Hm, thanks for reporting, can you guys get a sysrq+W trace when the system
reaches this state?

Thanks,
Nick
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