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

[Lance Yang]

On Thu, Feb 20, 2025 at 4:20 AM Waiman Long <llong@xxxxxxxxxx> wrote:
>
>
> 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.

Sounds good! Really looking forward to it ;p

Thanks,
Lance

>
> Cheers,
> Longman
>