RE: [????] Re: [PATCH][RFC] hung_task: Support to panic when the maximum number of hung task warnings is reached

["Li,Rongqing" <lirongqing@baidu.com>]

> -----Original Message-----
> From: Andrew Morton <akpm@linux-foundation.org>
> Sent: 2025年9月23日 11:46
> To: Li,Rongqing <lirongqing@baidu.com>
> Cc: corbet@lwn.net; lance.yang@linux.dev; mhiramat@kernel.org;
> paulmck@kernel.org; pawan.kumar.gupta@linux.intel.com; mingo@kernel.org;
> dave.hansen@linux.intel.com; rostedt@goodmis.org; kees@kernel.org;
> arnd@arndb.de; feng.tang@linux.alibaba.com; pauld@redhat.com;
> joel.granados@kernel.org; linux-doc@vger.kernel.org;
> linux-kernel@vger.kernel.org
> Subject: [????] Re: [PATCH][RFC] hung_task: Support to panic when the
> maximum number of hung task warnings is reached
> 
> On Tue, 23 Sep 2025 11:37:40 +0800 lirongqing <lirongqing@baidu.com> wrote:
> 
> > Currently the hung task detector can either panic immediately or
> > continue operation when hung tasks are detected. However, there are
> > scenarios where we want a more balanced approach:
> >
> > - We don't want the system to panic immediately when a few hung tasks
> >   are detected, as the system may be able to recover
> > - And we also don't want the system to stall indefinitely with multiple
> >   hung tasks
> >
> > This commit introduces a new mode (value 2) for the hung task panic behavior.
> > When set to 2, the system will panic only after the maximum number of
> > hung task warnings (hung_task_warnings) has been reached.
> >
> > This provides a middle ground between immediate panic and potentially
> > infinite stall, allowing for automated vmcore generation after a
> > reasonable
> 
> I assume the same argument applies to the NMI watchdog, to the softlockup
> detector and to the RCU stall detector?

True, especial RCU stall detector

> 
> A general framework to handle all of these might be better.  But why do it in
> kernel at all?  What about a userspace detector which parses kernel logs (or
> new procfs counters) and makes such decisions?


By leveraging existing kernel mechanisms, implementation in kernel is very simple and reliable, I think

Thanks

-Li