Date: Mon, 11 May 2009 09:49:30 -0400 From: John Baldwin <jhb@freebsd.org> To: pluknet <pluknet@gmail.com> Cc: freebsd-stable@freebsd.org Subject: Re: lock up in 6.2 (procs massively stuck in Giant) Message-ID: <200905110949.31142.jhb@freebsd.org> In-Reply-To: <a31046fc0905042041kdfcfa85u38e84db5197c929c@mail.gmail.com> References: <a31046fc0904292336w17aca317hefd32dad5bc28007@mail.gmail.com> <200905010949.45927.jhb@freebsd.org> <a31046fc0905042041kdfcfa85u38e84db5197c929c@mail.gmail.com>
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On Monday 04 May 2009 11:41:35 pm pluknet wrote:
> 2009/5/1 John Baldwin <jhb@freebsd.org>:
> > On Thursday 30 April 2009 2:36:34 am pluknet wrote:
> >> Hi folks.
> >>
> >> Today I got a new locking issue.
> >> This is the first time I got it, and it's merely reproduced.
> >>
> >> The box has lost both remote connection and local access.
> >> No SIGINFO output on the local console even.
> >> Jumping in ddb> shows the next:
> >>
> >> 1) first, this is a 8-way web server. No processes on runqueue except one
> > httpd
> >> (i.e. ps shows R in its state):
> >
> > You need to find who owns Giant and what that thread is doing. You can
try
> > using 'show lock Giant' as well as 'show lockchain 11568'.
> >
>
> Hi, John!
>
> Just reproduced now on another box.
> Hmm.. stack of the process owing Giant looks garbled.
>
> db> show lock Giant
> class: sleep mutex
> name: Giant
> flags: {DEF, RECURSE}
> state: {OWNED, CONTESTED}
> owner: 0xd0d79320 (tid 102754, pid 34594, "httpd")
>
> db> show lockchain 34594
> thread 102754 (pid 34594, httpd) running on CPU 7
> db> show lockchain 102754
> thread 102754 (pid 34594, httpd) running on CPU 7
The thread is running, so we don't know what it's top of stack is and you
can't a good stack trace in that case.
None of your CPUs are idle, so I don't think you have any sort of deadlock.
You might have a livelock.
--
John Baldwin
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