Re: "[PATCH] selftests/ftrace: Correctly enable event in instance-event.tc"

On Wed,  6 Sep 2023 19:56:52 +0530
Naresh Kamboju [off-list ref] wrote:

[my two cents]

I do see similar kernel panic while running ftrace testing on today's
Linux next-20230906 tag. This crash is from qemu-arm64.

Here I am providing steps to reproduced link and scripts by using tuxrun tool.
  - https://tuxapi.tuxsuite.com/v1/groups/linaro/projects/lkft/tests/2V0OqxEZUXIPNqWhQnnsuFOGYxR/reproducer
  

[..]

Log details,
-------------
# ok 45 ftrace - test tracing error log support
<47>[ 1373.662292] systemd-journald[90]: Sent WATCHDOG=1 notification.
# ok 46 Test creation and deletion of trace instances while setting an event

It's definitely a race with the creation and deletion of instances.

I'm going to run it on my laptop VM and see if that reproduces it. My other
VM is on a pretty powerful machine, and perhaps that's keeping it from
hitting the race.

-- Steve

<1>[ 1382.873224] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000030
<1>[ 1382.873223] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000030
<1>[ 1382.873426] Mem abort info: