Re: [PATCH 2/2] scftorture: Use a lock-less list to free memory.

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

On 2024-11-04 17:00:19 [-0800], Boqun Feng wrote:
> Hi Sebastian,
Hi Boqun,

…
> I think this needs to be:
> 
> 		scf_cleanup_free_list(cpu);
> 
> or
> 
> 		scf_cleanup_free_list(curcpu);
> 
> because scfp->cpu is actually the thread number, and I got a NULL
> dereference:
> 
> [   14.219225] BUG: unable to handle page fault for address: ffffffffb2ff7210

Right. Replaced with cpu.
…
> 
> Another thing is, how do we guarantee that we don't exit the loop
> eariler (i.e. while there are still callbacks on the list)? After the
> following scftorture_invoke_one(), there could an IPI pending somewhere,
> and we may exit this loop if torture_must_stop() is true. And that IPI
> might add its scf_check to the list but no scf_cleanup_free_list() is
> going to handle that, right?

Okay. Assuming that IPIs are done by the time scf_torture_cleanup is
invoked, I added scf_cleanup_free_list() for all CPUs there.

Reposted at
	https://lore.kernel.org/20241107111821.3417762-1-bigeasy@linutronix.de

> Regards,
> Boqun

Sebastian