Re: frequent lockups in 3.18rc4

[Will Deacon]

On Thu, Dec 04, 2014 at 02:56:31PM +0000, Dave Jones wrote:
> On Thu, Dec 04, 2014 at 10:51:03AM +0000, Will Deacon wrote:
> 
>  > and, as before, it has a weird child process that I can't backtrace:
>  > 
>  > trinity-c1      R  running task        0   861    811 0x00000000
>  > Call trace:
> 
> When I get these, ftrace is a godsend.
> 
> cd /sys/kernel/debug/tracing/
> echo 861 >> set_ftrace_pid
> echo function_graph >> current_tracer
> echo 1 >> tracing_on
> wait a little while
> cat trace > trace.txt
> 
> repeat last two steps if necessary
> 
> (assuming it's stuck in kernel space, which /proc/861/stack should
>  be able to confirm. Usually when I see this problem, that just shows
>  0xffffffffffffffff)

That would be great if I had a working shell :)

I tried enabling the thing before starting trinity, in the hope of dumping
the buffer using sysrq, but now I seem to have hit an unrelated panic in
the ftrace code.

Will
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