Re: [PATCH] riscv: ftrace: Properly acquire text_mutex to fix a race condition

[Palmer Dabbelt]

On Wed, 09 Jul 2025 09:45:36 PDT (-0700), rostedt@xxxxxxxxxxx wrote:
> On Wed, 09 Jul 2025 07:12:47 -0700 (PDT)
> Palmer Dabbelt <palmer@xxxxxxxxxxx> wrote:
>
> > >  #ifdef CONFIG_DYNAMIC_FTRACE
> > > +void ftrace_arch_code_modify_prepare(void)
> > > +{
> > > +	mutex_lock(&text_mutex);
> > > +}
> > > +
> > > +void ftrace_arch_code_modify_post_process(void)
> > > +{
> > > +	mutex_unlock(&text_mutex);
> > > +}
> >
> > IIRC there's a reason we don't do it this way, we had (or had tried to)
> > have it before.  It's been a while, though, and I'm just having some a
> > coffee so may I'm just wrong...
>
> Yes, because it caused issues with stop machine[1], but if you are no
> longer using stop machine, this should be what you should do now.
>
> [1] https://lore.kernel.org/all/20220310045454.672097-1-changbin.du@xxxxxxxxx/

Thanks.  The v2 staged for the tester, should show up on fixes soon.

> -- Steve