Messages in this thread | | | Date | Fri, 5 Sep 2008 11:22:21 -0700 | From | Andrew Morton <> | Subject | Re: 2.6.26.3 mount process looping on ext3 rw remount |
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On Fri, 5 Sep 2008 13:39:02 +0200 Marc Haber <mh+linux-kernel@zugschlus.de> wrote:
> On Mon, Aug 25, 2008 at 06:35:28PM -0700, Andrew Morton wrote: > > Please try to get a kernel profile while it's happening. oprofile > > maybe, or just the plain old timer-based profiler. There's some info > > in Documentation/basic_profiling.txt. > > I'll boot my next kernel with profile=2. > > > Actually, a simple alternative is to hit sysrq-P five or ten times. > > Most of the resulting stack traces will point back at where the CPU is > > stuck. > > Where are they written to? "P" in a sysrqd telnet session does not > result in anything being written to the kernel log or to dmesg.
alt-sysrq-p from the attached keyboard.
When operating remotely, use `echo p > /proc/sysrq-trigger'.
The output will be in /var/log/messages and is accessible via `dmesg -s 1000000'.
Please avoid email client wordwrapping when sending these logs. 99% of people do this and it makes the text very hard to read.
> > This gets a bit hit-or-miss if you have multiple CPUs, because the > > sysrq-p trace can land on the wrong CPU. We recently added a sysrq-l > > which will generate a trace on all CPUS. > > "l" results in the SysRq HELP being written to the kernel log, so I > guess that "recently" means "not yet in 2.6.26.3".
ok
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