From: Mike Galbraith <bitbucket@online.de>
To: Ken Moffat <zarniwhoop@ntlworld.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: 3.13.5 : rm -rf running forever, one cpu at approx 100%
Date: Thu, 27 Feb 2014 05:52:42 +0100 [thread overview]
Message-ID: <1393476762.5519.35.camel@marge.simpson.net> (raw)
In-Reply-To: <20140227034535.GC14346@milliways>
On Thu, 2014-02-27 at 03:45 +0000, Ken Moffat wrote:
> On Thu, Feb 27, 2014 at 04:26:35AM +0100, Mike Galbraith wrote:
> >
> > I would start with strace to see if a task is looping in userspace, then
> > move on to perf top -g -p <pid> (or perf record/report) to peek at what
> > it's up to in the kernel. Once you have the where, trace_printk() is
> > the best thing since sliced bread (which ranks just below printk()).
> >
> > -Mike
> Thanks. I'll need to build perf.
You may want to build the kernel with frame-pointers too, for easy gdb
list *0x(hexnum) of *func()+0x(hexoffset) use. Crash is also pretty
handy both for rummaging live via crash vmlinux /proc/kcore, and for
leisurely postmortem analysis if you set the box up to crashdump in
advance, and force a dump (poke sysrq-c or echo c > /proc/sysrq-trigger)
when you see the bad thing happen. Crash has all kinds of goodies,
including invocation of gdb.
-Mike
next prev parent reply other threads:[~2014-02-27 4:52 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-27 0:52 Ken Moffat
2014-02-27 1:28 ` Gene Heskett
2014-02-27 1:47 ` Ken Moffat
2014-02-27 1:57 ` Gene Heskett
2014-02-27 3:26 ` Mike Galbraith
2014-02-27 3:45 ` Ken Moffat
2014-02-27 4:19 ` Gene Heskett
2014-02-27 4:52 ` Mike Galbraith [this message]
2014-02-27 11:30 ` Gene Heskett
2014-03-03 21:16 ` Ken Moffat
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