Re: [PATCH 0/2] hung_task: Dump the blocking task stacktrace

[Waiman Long]

On 2/19/25 10:02 AM, Lance Yang wrote:
> On Wed, Feb 19, 2025 at 9:33 PM Lance Yang <ioworker0@xxxxxxxxx> wrote:
> > CC linux-mm
> >
> > On Wed, Feb 19, 2025 at 9:00 PM Masami Hiramatsu (Google)
> > <mhiramat@xxxxxxxxxx> wrote:
> > > Hi,
> > >
> > > The hung_task detector is very useful for detecting the lockup.
> > > However, since it only dumps the blocked (uninterruptible sleep)
> > > processes, it is not enough to identify the root cause of that
> > > lockup.
> > >
> > > For example, if a process holds a mutex and sleep an event in
> > > interruptible state long time, the other processes will wait on
> > > the mutex in uninterruptible state. In this case, the waiter
> > > processes are dumped, but the blocker process is not shown
> > > because it is sleep in interruptible state.
> Cool! I just ran into something similar today, but with rwsem. In that
> case, the blocked process was locked up, and we could not identify
> the root cause either ;(

Once this patch series is settled down, we can extend rwsem to provide 
similar feature.

Cheers,
Longman