How to debug hard lockup issue

Thu Aug 2 03:15:30 EDT 2012

Hello,

On Thu, Aug 02, 2012 at 11:03:31AM +0800, Lin Ming wrote:
> I encountered a hard lockup on a armv5 board with 2.6.32 kernel.
> There is no any message output since it is hard lockup.
> 
> I tried watchdog, but watchdog can only reset the board. I still can't
> get any info.
> 
> The hard lockup is possibly because kernel blocked/looped with
> interrupts disabled.
> 
> Is there any non-maskable interrupt I can use to dump the kernel stack?
> Or any other hint?
Try enabling various debug options. The following come to (my) mind:

CONFIG_DETECT_HUNG_TASK
CONFIG_PROVE_LOCKING
CONFIG_DEBUG_ATOMIC_SLEEP
CONFIG_MAGIC_SYSRQ

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |