Multi processor locking problem under 7.0

Kris Kennaway kris at FreeBSD.org
Wed Jan 30 01:40:41 PST 2008


Dennis Glatting wrote:

>>> There are no errors on the screen but it no longer proceeds with the 
>>> port build. When I suspend the process and restart the make in the 
>>> same session it has no problem getting past this impasse and with a 
>>> few suspends the make finishes without error. It does not happen 
>>> every time which is very odd.
>>>
>>> Based on your description above it seems like it may be the same problem.
>>>
>>> What do you think?
>> If you have threads blocked on "vmo_de" then upgrade to the latest RELENG_7 or 
>> RELENG_7_0 (specifically the sys/kern/subr_sleepqueue.c file) and try again.
>>
> 
> I got the right file and updated my systems. I ran dump on the IBM
> system five times. Dump hung four times, three times when 99.99%
> complete. Below is a ps output.
> 
> How do I tell what the threads are blocked on?
> 
> 
> Daffy> ps -axwHl | grep dump
>     0   801     1   0  96  0 20952  4060 select Is    ??
> 0:00.00 /usr/sbin/sshd -f /etc/ssh/dumper/sshd_config
>     0 14682   870   0   8  0 34388 26628 wait   I+    p0    0:00.20 dump
> 0uaLCf 24 /dev/null /usr (dump)
>     0 14774 14682   0   4  0 34388 30680 sbwait I+    p0    0:01.01
> dump: /dev/aacd0s1e: pass 4: 14.97% done, finished in 0:03 at T
>     0 14775 14774   0  20  0 34388 26644 pause  I+    p0    0:00.69 dump
> 0uaLCf 24 /dev/null /usr (dump)
>     0 14776 14774   0  20  0 34388 26644 pause  I+    p0    0:00.69 dump
> 0uaLCf 24 /dev/null /usr (dump)
>     0 14777 14774   0  20  0 34388 26644 pause  I+    p0    0:00.69 dump
> 0uaLCf 24 /dev/null /usr (dump)
>   600 14896 12552   0  96  0  5900  1184 -      R+    p2    0:00.00 grep
> dump

The wait channel is the "select/wait/..." column, but your problem is 
known and is believed to be unrelated to what John said.  He was 
addressing the other respondent ("Paul") who described an apparently 
unrelated problem where dump is not in play at all (and which has 
different symptoms).

Kris


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