Re: sync-Regression in 2.6.28.2?

[Federico Cuello <fedux@lugmen.org.ar>]

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.