Messages in this thread | | | Date | Sat, 29 Sep 2007 17:54:32 +0200 (CEST) | From | Krzysztof Oledzki <> | Subject | Re: Strange system hangs |
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On Sat, 29 Sep 2007, Nick Piggin wrote:
> On Friday 28 September 2007 18:42, Krzysztof Oledzki wrote: >> Hello, >> >> I am experiencing weird system hangs. Once about 2-5 weeks system freezes >> and stops accepting remote connections, so it is no longer possible to >> connect to most important services: smtp (postfix), www (squid) or even >> ssh. Such connection is accepted but then it hangs. >> >> What is strange, that previously established ssh session is usable. It is >> possible to work on such system until you do something stupid like "less >> /var/log/all.log". Using strace I found that process blocks on: > > Is this a regression? If so, what's the most recent kernel that didn't show > the problem?
I don't know. First kernel I ran was 2.6.20.x. This is quite fresh system.
> The symptoms could be consistent with some place doing a > balance_dirty_pages while holding a lock that is required for IO, but I can't > see a smoking gun (you've got contention on i_mutex, but that should be > OK). > > Can you see if there is any memory under writeback that isn't being > completed (sysrq+M), also a list the locks held after the hang might be > helpful (compile in lockdep and sysrq+D)
OK. I'll try to do it next time if there will be a chance. It may take some time, BTW.
> Is anything currently running? (sysrq+P and even a full sysrq+T task list > could be useful).
I'll have to check - maybe I have this captured. If not I'll check it next time.
> Are any IO errors occurring at all?
Didn't notice - so no.
Thank you.
Best regards,
Krzysztof Olędzki
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