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Date: Tue, 16 Sep 2008 09:42:03 -0700
From: Alfred Perlstein <alfred@freebsd.org>
To: Ivan Voras <ivoras@freebsd.org>
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Subject: Re: Apache-worker stuck at 100% CPU
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* Ivan Voras <ivoras@freebsd.org> [080916 02:12] wrote:
> 2008/9/16 Alfred Perlstein <alfred@freebsd.org>:
> > * Ivan Voras <ivoras@freebsd.org> [080915 16:05] wrote:
> 
> >> >> How do I pick what thread to backtrace in gdb?
> >> >
> >> > i think the command is 'info threads' or 'show
> >> > threads' then i think you just type
> >> > 'thread FOO' to select the thread.
> >>
> >> Both commands don't work / don't exist. Any others?
> >>
> >> (background: apache22-worker port, no mod_php, on 7.0 and 7-STABLE
> >> suddenly gets stuck at 100% CPU; the same setup worked on 6-STABLE.
> >> I'm looking for ideas)
> >
> > I'm sorry, I really can't help at this point other than to look
> > through the documents myself to figure out how to do a backtrace/select
> > threads.
> >
> > Give it a shot, and let us know and we can go further.
> 
> Sorry, I should have been more verbose - "info threads" should work
> but it doesn't - I can attach and get threads from a "regular"
> multithreaded process, but when yesterday when I attached to the stuck
> process, I couldn't get the list of threads. I'll try again the next
> time it gets stuck and try to provide more information.

If it happens again, you could try sending it a SIGABRT or SEGV
and then trying to diagnose the core dump.

Or try using gcore to generate a coredump and debug that.

-- 
- Alfred Perlstein