Re: [PATCH] ftrace: Remove possible deadlock between register_kprobe() and ftrace_run_update_code()

From: Steven Rostedt
Date: Fri Jun 28 2019 - 11:46:33 EST


On Fri, 28 Jun 2019 09:54:24 -0400
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> On Fri, 28 Jun 2019 12:52:32 +0200
> Petr Mladek <pmladek@xxxxxxxx> wrote:
>
> > On Fri 2019-06-28 09:32:03, Miroslav Benes wrote:
> > > On Thu, 27 Jun 2019, Petr Mladek wrote:
> > > > @@ -2611,12 +2610,10 @@ static void ftrace_run_update_code(int command)
> > > > {
> > > > int ret;
> > > >
> > > > - mutex_lock(&text_mutex);
> > > > -
> > > > ret = ftrace_arch_code_modify_prepare();
> > > > FTRACE_WARN_ON(ret);
> > > > if (ret)
> > > > - goto out_unlock;
> > > > + return ret;
> > >
> > > Should be just "return;", because the function is "static void".
> >
> > Grr, I usually check compiler warnings but I evidently skipped it
> > in this case :-(
> >
> > Steven, should I send a fixed/folloup patch or will you just
> > fix it when pushing?
> >
>
> I'll fix it up.

Also note, this would have been caught with my test suite, as it checks
for any new warnings.

-- Steve