Re: sync-Regression in 2.6.28.2?

[Nick Piggin <nickpiggin@yahoo.com.au>]

On Wednesday 28 January 2009 08:09:10 Federico Cuello wrote:
> Ralf Hildebrandt escribió:
> > 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