Re: [PATCH v2 5/5] workqueue: Add stall detector sample module

[Song Liu]

On Thu, Mar 5, 2026 at 8:16 AM Breno Leitao <leitao@xxxxxxxxxx> wrote:
>
> Add a sample module under samples/workqueue/stall_detector/ that
> reproduces a workqueue stall caused by PF_WQ_WORKER misuse.  The
> module queues two work items on the same per-CPU pool, then clears
> PF_WQ_WORKER and sleeps in wait_event_idle(), hiding from the
> concurrency manager and stalling the second work item indefinitely.

Clearing PF_WQ_WORKER is an interesting way to trigger the stall.

>
> This is useful for testing the workqueue watchdog stall diagnostics.
>
> Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>

Acked-by: Song Liu <song@xxxxxxxxxx>

> ---
>  samples/workqueue/stall_detector/Makefile   |  1 +
>  samples/workqueue/stall_detector/wq_stall.c | 98 +++++++++++++++++++++++++++++
>  2 files changed, 99 insertions(+)