Re: [PATCH] kernel/trace: Stop and wait for kthread on preempt irq module unload

[Xiao Yang]

On 2020/4/28 22:45, Steven Rostedt wrote:
> diff --git a/kernel/trace/preemptirq_delay_test.c b/kernel/trace/preemptirq_delay_test.c
> >  index 1c28ca20e30b..6d9131ae7e8c 100644
> >  --- a/kernel/trace/preemptirq_delay_test.c
> >  +++ b/kernel/trace/preemptirq_delay_test.c
> >  @@ -113,15 +113,27 @@ static int preemptirq_delay_run(void *data)
> >
> >    	for (i = 0; i<  s; i++)
> >    		(testfuncs[i])(i);
> >  +
> >  +	while (!kthread_should_stop()) {
> >  +		schedule();
> >  +		set_current_state(TASK_INTERRUPTIBLE);
> >  +	}
> >  +
> >  +	__set_current_state(TASK_RUNNING);
> >  +
> >    	return 0;
> >    }
Hi Steven,

Thanks for your patch.

I also used the following steps to do test and didn't get any 
warning/panic after applying your patch.
---------------------------------
for i in $(seq 1 100); do modprobe preemptirq_delay_test test_mode=irq 
delay=500000; rmmod preemptirq_delay_test; done
for i in $(seq 1 100); do modprobe preemptirq_delay_test 
test_mode=preempt delay=500000; rmmod preemptirq_delay_test; done
---------------------------------

But I am not sure which fix(from you and Joel) is better.

Thanks,
Xiao Yang