Re: [patch] voluntary-preempt-2.6.9-rc1-bk4-R3

["K.R. Foley" <kr@cybsft.com>]

Ingo Molnar wrote:
> * Ingo Molnar <mingo@elte.hu> wrote:
> 
> 
>>i'll add a new feature to debug this: when crashing on an assert and
>>tracing is enabled the trace leading up to the crash will be printed
>>to the console. [...]
> 
> 
> the -R3 patch has this feature:
> 
>   http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.9-rc1-bk4-R3 
> 
> you can enable it via enabling CONFIG_LATENCY_TRACE and doing:
> 
>   echo 3 > /proc/sys/kernel/trace_enabled
> 
> it's all automatic from this point on: tracing will happen nonstop and
> any assert or crash that prints the process stack will also print the
> last 100 trace entries. Sample output:
> 
>  Call Trace:
>   [<c0160401>] sys_munmap+0x61/0x80
>   [<c010520d>] sysenter_past_esp+0x52/0x71
>  Last 100 trace entries:
>  00000001: zap_pmd_range+0xe/0x90  <= (unmap_page_range+0x55/0x80)
>  00000001: stop_trace+0x8/0x20  <= (bust_spinlocks+0x20/0x60)
>  00000001: bust_spinlocks+0xe/0x60  <= (die+0xbc/0x2a0)
>  [... 97 more trace entries ...]
> 
> Please capture and mail the first 'extended' oops that triggers
> (secondary followup traces are probably just side-effects of the crash),
> it could give us clues about where the bug is.
> 
> 	Ingo
> 

Building now.

kr