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

[Steven Rostedt]

On Wed, 09 Jul 2025 07:12:47 -0700 (PDT)
Palmer Dabbelt <palmer at dabbelt.com> 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@gmail.com/

-- Steve