2022-05-06 13:10:55

by Tiezhu Yang

Subject: [PATCH 1/2] selftests/ftrace: Save kprobe_events to test log

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

Signed-off-by: Tiezhu Yang <[email protected]>
---
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

2022-05-09 09:01:46

by Masami Hiramatsu

Subject: Re: [PATCH 1/2] selftests/ftrace: Save kprobe_events to test log

On Thu, 5 May 2022 20:19:07 +0800
Tiezhu Yang <[email protected]> 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 <[email protected]>

Thank you,

>
> Signed-off-by: Tiezhu Yang <[email protected]>
> ---
> 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 <[email protected]>