Re: [linus:master] [selftests/tracing] c5c413534d: kselftests-bpf.ftrace.ftracetest-ktap._instance_event_trigger_-_test_poll_wait_on_histogram.fail

On Mon, 20 Jul 2026 23:29:52 +0900
Masami Hiramatsu (Google) <[email protected]> wrote:

> On Thu, 16 Jul 2026 22:30:11 +0800
> kernel test robot <[email protected]> wrote:
> 
> > 
> > 
> > 
> > Hello,
> > 
> > in fact, we found below two test cases randomly failed upon c5c413534d, while
> > keep succeed on parent:
> > 
> > =========================================================================================
> > tbox_group/testcase/rootfs/kconfig/compiler/group:
> >   igk-rpl-d04/kselftests-bpf/debian-13-x86_64-20250902.cgz/x86_64-rhel-9.4-bpf/gcc-14/ftrace
> > 
> > 22a78be4123dce81 c5c413534d40eb4c982f1794e62
> > ---------------- ---------------------------
> >        fail:runs  %reproduction    fail:runs
> >            |             |             |
> >            :31          52%          16:32    kselftests-bpf.ftrace.ftracetest-ktap._instance_event_trigger_-_test_poll_wait_on_histogram.fail
> >            :31          29%           9:32    kselftests-bpf.ftrace.ftracetest-ktap.event_trigger_-_test_poll_wait_on_histogram.fail
> > 
> > 
> > 
> > kernel test robot noticed "kselftests-bpf.ftrace.ftracetest-ktap._instance_event_trigger_-_test_poll_wait_on_histogram.fail" on:
> > 
> > commit: c5c413534d40eb4c982f1794e62813f926aba747 ("selftests/tracing: Have trigger-hist-poll.tc use sched_process_exit")
> > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
> > 
> > [test failed on linux-next/master 49362394dad7df66c274c867a271394c10ca2bb8]
> 
> Hmm, this seems like a scheduler (event) behavior is different from what
> the test expected.
> 
> Steve, I think we should use another deterministic events.

I've sent a fix.

https://lore.kernel.org/all/178459323652.354837.10711230683477156733.stgit@devnote2/

But this drops 2 checkpoints. I think we need to use another deterministic
event, like trace_marker (but trace_marker does not support histogram trigger)

Thanks,


> 
> Thank you,
> 
> -- 
> Masami Hiramatsu (Google) <[email protected]>


-- 
Masami Hiramatsu (Google) <[email protected]>