Re: [PATCH V3] firmware: google: Test spinlock on panic path to avoid lockups

From: Andrew Morton
Date: Thu Sep 01 2022 - 18:14:45 EST


On Thu, 1 Sep 2022 16:02:08 -0300 "Guilherme G. Piccoli" <gpiccoli@xxxxxxxxxx> wrote:

> On 01/09/2022 15:59, Greg KH wrote:
> > [...]
> > Ick, I don't know, this all feels odd. I want someone else to review
> > this and give their ack on the patch before I'll take it so someone else
> > can share in the blame :)
> >
> > thanks,
> >
> > greg k-h
>
> LOL, that's OK for me! Evan seems to be fine with it BTW.
>
> Let's see if Petr can jump in, also adding Andrew here since he's
> usually merging stuff for panic.

Are the usual gsmi developers not operational?

Patch seems sensible to me, although the deadlock sounds pretty
theoretical. A better code comment might be simply

/*
* Panic callbacks are executed with all other CPUs stopped, so we must
* not attempt to spin waiting for gsmi_dev.lock to be released.
*/

?