Re: A panic a day

From: Steve Kargl <sgk_at_troutmask.apl.washington.edu>
Date: Fri, 23 Sep 2022 16:46:08 UTC
On Thu, Sep 22, 2022 at 03:00:53PM -0400, Mark Johnston wrote:
> 
> I think this untested patch will address the panics.  The bug was there
> for a long time but some recent restructuring added an assertion which
> caught it.
> 
> diff --git a/sys/kern/sched_4bsd.c b/sys/kern/sched_4bsd.c
> index 9d48aa746f6d..484864b66c1c 100644
> --- a/sys/kern/sched_4bsd.c
> +++ b/sys/kern/sched_4bsd.c
> @@ -1282,9 +1282,10 @@ kick_other_cpu(int pri, int cpuid)
>  	}
>  #endif /* defined(IPI_PREEMPTION) && defined(PREEMPTION) */
>  
> -	ast_sched_locked(pcpu->pc_curthread, TDA_SCHED);
> -	ipi_cpu(cpuid, IPI_AST);
> -	return;
> +	if (pcpu->pc_curthread->td_lock == &sched_lock) {
> +		ast_sched_locked(pcpu->pc_curthread, TDA_SCHED);
> +		ipi_cpu(cpuid, IPI_AST);
> +	}
>  }
>  #endif /* SMP */
>  
> @@ -1397,7 +1398,7 @@ sched_add(struct thread *td, int flags)
>  
>  	cpuid = PCPU_GET(cpuid);
>  	if (single_cpu && cpu != cpuid) {
> -	        kick_other_cpu(td->td_priority, cpu);
> +		kick_other_cpu(td->td_priority, cpu);
>  	} else {
>  		if (!single_cpu) {
>  			tidlemsk = idle_cpus_mask;

Mark,

My system has been running a fairly heavy load with this
patch for the last 20 or so hours without any incidences.
In fact, the system feels snappier.  Thanks for the quick
response with a patch.

-- 
Steve