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Date:   Thu, 23 Mar 2023 23:01:05 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Yafang Shao <laoar.shao@gmail.com>
Cc:     mhiramat@kernel.org, alexei.starovoitov@gmail.com,
        linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org,
        Andrii Nakryiko <andrii.nakryiko@gmail.com>,
        Jiri Olsa <olsajiri@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>
Subject: Re: [PATCH] tracing: Refuse fprobe if RCU is not watching
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On Fri, 24 Mar 2023 10:51:49 +0800
Yafang Shao <laoar.shao@gmail.com> wrote:

> On Thu, Mar 23, 2023 at 8:39 PM Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > On Thu, 23 Mar 2023 13:59:34 +0800
> > Yafang Shao <laoar.shao@gmail.com> wrote:
> >  
> > > I have verified the latest linux-trace tree,
> > >     git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
> > > trace/core
> > >
> > > The result of "uname -r" is ''6.3.0-rc3+".
> > > This issue still exists, and after applying this patch it disappears.
> > > It can be reproduced with a simple bpf program as follows,
> > >     SEC("kprobe.multi/preempt_count_sub")
> > >     int fprobe_test()
> > >     {
> > >         return 0;
> > >     }  
> >
> > Still your patch is hiding a bug, not fixing one.
> >
> > Can you apply this patch and see if the bug goes away?
> >  
> 
> I have verified that the bug goes away after applying this patch.
> Thanks for the fix.
> 

It's in tip:

  https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?h=x86/urgent&id=f87d28673b71b35b248231a2086f9404afbb7f28

Hopefully it will make it to mainline soon.

-- Steve