Re: [PATCH] kernel/hung_task.c: force ignore_loglevel before panic

[Petr Mladek]

On Wed 2018-12-12 01:16:11, Liu, Chuansheng wrote:
> 
> 
> > -----Original Message-----
> > From: Tetsuo Handa [mailto:penguin-kernel@xxxxxxxxxxxxxxxxxxx]
> > Sent: Tuesday, December 11, 2018 6:02 PM
> > To: Liu, Chuansheng <chuansheng.liu@xxxxxxxxx>; Sergey Senozhatsky
> > <sergey.senozhatsky.work@xxxxxxxxx>
> > Cc: akpm@xxxxxxxxxxxxxxxxxxxx; pmladek@xxxxxxxx;
> > sergey.senozhatsky@xxxxxxxxx; rostedt@xxxxxxxxxxx; dvyukov@xxxxxxxxxx;
> > linux-kernel@xxxxxxxxxxxxxxx
> > Subject: Re: [PATCH] kernel/hung_task.c: force ignore_loglevel before panic
> > 
> > On 2018/12/11 10:16, Liu, Chuansheng wrote:
> > > We may enhance it by:
> > > -       if (sysctl_hung_task_warnings) {
> > > +       if (sysctl_hung_task_panic || sysctl_hung_task_warnings) {
> > >                 if (sysctl_hung_task_warnings > 0)
> > >                         sysctl_hung_task_warnings--;
> > 
> > Why ignore sysctl_hung_task_warnings? The administrator can already
> > configure as sysctl_hung_task_warnings == -1 && sysctl_hung_task_panic == 1
> > if he/she does not want to suppress neither sched_show_task() nor
> > debug_show_all_locks()/trigger_all_cpu_backtrace(). Someone might want that
> > sysctl_hung_task_warnings == 0 (which is a request to suppress only
> > sched_show_task()) should not be ignored by sysctl_hung_task_panic == 1
> > (which is a request to trigger panic).
> 
> 
> My complete idea is in patch V1 which has been sent. Paste here:
> If sysctl_hung_task_panic == 1, I will force sched_show_task(t) and set
> hung_task_call_panic = true
> hung_task_show_lock = true

Please, do not mix two changes into one patch.

Add console_verbose() in one patch. It is simple and
everyone has agreed with it so far.

Force sched_show_task() when hung_task_call_panic == 1 in
another patch. It seems to be controversial and should be
discussed/changed separately.

Best Regards,
Petr