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Subject: Re: [RESEND PATCH v2] trace: prevent preemption in
 perf_ftrace_function_call()
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        Ingo Molnar <mingo@redhat.com>,
        open list <linux-kernel@vger.kernel.org>,
        Jiri Olsa <jolsa@redhat.com>
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Date:   Tue, 12 Oct 2021 13:51:13 +0800
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On 2021/10/11 下午10:45, Peter Zijlstra wrote:
[snip]
>>>
>>> Oh, I might've gotten that wrong, I assumed regular trylock semantics,
>>> but it doesn't look like that's right.
>>
>> I will use bit instead ret and give some testing :-)
>>
>> BTW, would you prefer to merge these changes into this patch or maybe send
>> another patch with your suggested-by?
> 
> Yeah, please send another patch; once you've confirmed it actually works
> etc.. I did this before waking (as evidence per the above), who knows
> what else I did wrong :-)

I've send the:
  [PATCH 0/2] ftrace: make sure preemption disabled on recursion testing

should have taking care all the places, but only testing with x86 since I
got no machine for other arch... just by logically it should be fine.

Regards,
Michael Wang

>