arm64/juno-r2: Kernel panic in cgroup_fj_stress.sh on next-20250904

[John Stultz]

On Fri, Sep 5, 2025 at 6:21 AM Naresh Kamboju <naresh.kamboju at linaro.org> wrote:
>
> Kernel warnings and a panic were observed on Juno-r2 while running
> LTP controllers (cgroup_fj_stress.sh) on the Linux next-20250904 with
> SCHED_PROXY_EXEC=y enabled build.
>
> Regression Analysis:
> - New regression? yes
> - Reproducibility? yes
>
> First seen on next-20250904
> Bad: next-20250904
> Good: next-20250822
>
> Test regression: next-20250904 juno-r2 cgroup_fj_stress.sh kernel panic
>
> Reported-by: Linux Kernel Functional Testing <lkft at linaro.org>

Thank you for the testing and the report here!

> Juno-r2:
>  * LTP controllers
>    * cgroup_fj_stress.sh
>
> Test crash:
> cgroup_fj_stress_net_cls_1_200_one:
> [  365.917504] /usr/local/bin/kirk[402]: cgroup_fj_stress_net_cls_1_200_one:
> start (command: cgroup_fj_stress.sh net_cls 1 200 one)
> [  374.230110] ------------[ cut here ]------------
> [  374.230132] WARNING: lib/timerqueue.c:55 at
> timerqueue_del+0x68/0x70, CPU#5: swapper/5/0

This looks like we are removing a timer that was already removed from the queue.

I don't see anything obvious right away in the delta that would clue
me into what's going on, but I'll try to reproduce this.

thanks
-john