Re: [PATCH v4 2/2] tracing: Drain deferred trigger frees if kthread creation fails

[Steven Rostedt]

On Fri, 27 Mar 2026 16:41:52 -0600
Wesley Atwell <atwellwea@xxxxxxxxx> wrote:

> Yes,
> 
> This kernel command line reliably reaches trigger_data_free() during boot:
> 
> trace_event=sched:sched_switch
> trace_trigger=sched_switch.traceon,sched_switch.traceon
> 
> On an unpatched tree, that crashes during early boot before userspace.
> The call trace goes through:
> 
> trigger_data_free()
> __kthread_create_on_node()
> try_to_wake_up()
> 
> The stack also shows the boot-time trigger registration path:
> 
> event_trigger_parse()
> trigger_process_regex()
> __trace_early_add_events()

Thanks for this. I can reproduce the crash. I'm also going to add this
to the change log as it is useful (I'll even add it to one of my
regression tests). I'll take this patch separately (this didn't need to
be a patch series, as the two patches do not depend on each other).

-- Steve