Re: (ltc-kernel 7837) Re: [BUG] 3.13-rc1 kernel crash when enable all tracepoints

[Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>]

(2013/11/26 15:33), Masami Hiramatsu wrote:
> (2013/11/26 13:38), Jovi Zhangwei wrote:
>> Hi,
>>
>> I'm not sure this issue already be fixed or not, it can be reproduced
>> permanently.
>>
>> (I didn't use git-bisect yet, you guys might can understand it quickly)
>>
>> #echo 1 > /sys/kernel/debug/tracing/events/enable
> 
> Thanks for reporting. I could reproduce it.
> 
> To narrow this down, I tried to run the below command
> 
> [tracing]# for i in events/*/*/enable ; do echo $i; echo 1 > $i; done
> 
> And it ran through the end without any problem.
> Hm, next I checked the difference of available_events and set_event.
> 
> [tracing]# diff available_events set_event
> 283d282
> < ftrace:function
> 
> So, I guess it was caused by enabling ftrace:function, and
> it is unable to do that via set_event, nor events/ftrace/enable
> I'm not sure how, but it seems that ftrace:function can be
> enabled by the events/enable.

Oops, No, forget it. When I added a printk in
ftrace_set_clr_event_nolock(), it didn't happen and ftrace/function
is not enabled.

I'm trying to reproduce it on the latest tip kernel again on KVM,
but not yet reproduced.

Thank you,

-- 
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com