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Date:   Fri, 6 May 2022 10:46:21 +0900
From:   Masami Hiramatsu <mhiramat@kernel.org>
To:     Tiezhu Yang <yangtiezhu@loongson.cn>
Cc:     Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Steven Rostedt <rostedt@goodmis.org>,
        Shuah Khan <shuah@kernel.org>,
        Xuefeng Li <lixuefeng@loongson.cn>, linux-mips@vger.kernel.org,
        linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] selftests/ftrace: Save kprobe_events to test log
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        <1651753148-1464-2-git-send-email-yangtiezhu@loongson.cn>
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On Thu,  5 May 2022 20:19:07 +0800
Tiezhu Yang <yangtiezhu@loongson.cn> wrote:

> It may lead to kernel panic when execute the following testcase on mips:
> 
>   # ./ftracetest test.d/kprobe/multiple_kprobes.tc
> 
> A preliminary analysis shows that the issue is related with
> 
>   echo 1 > events/kprobes/enable
> 
> after add the 256 probe points.
> 
> In order to find the root cause, I want to verify which probe point has
> problem, so it is necessary to save kprobe_events to test log.
> 
> With this patch, we can get the 256 probe points in the test log through
> the following command:
> 
>   # ./ftracetest test.d/kprobe/multiple_kprobes.tc -vvv -k

This looks good to me. :)

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

Thank you,

> 
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
>  tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc b/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc
> index 312d237..be754f5 100644
> --- a/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc
> +++ b/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc
> @@ -25,6 +25,8 @@ if [ $L -ne 256 ]; then
>    exit_fail
>  fi
>  
> +cat kprobe_events >> $testlog
> +
>  echo 1 > events/kprobes/enable
>  echo 0 > events/kprobes/enable
>  echo > kprobe_events
> -- 
> 2.1.0
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>