On 2023/9/7 05:37, Steven Rostedt wrote:
On Wed, 6 Sep 2023 10:37:18 -0400 Steven Rostedt rostedt@goodmis.org wrote:
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.
Putting in a while loop of:
# while :; do ./ftracetest test.d/instances/instance-event.tc ; done
In test.d/instances/instance-event.tc, concurrently create/delete/access intances just about 1 second and then killed them, it may cause missing the race.
No longer sleep and kill, following testcase can also reproduce: ``` #!/bin/bash
cd /sys/kernel/tracing/instances
instance_slam() { while :; do mkdir foo 2> /dev/null rmdir foo 2> /dev/null done }
instance_set() { while :; do echo 1 > foo/events/sched/sched_switch/enable done 2> /dev/null }
instance_slam & p1=$! echo $p1
instance_set & p2=$! echo $p2 ```
--
Thanks, Zheng Yejian
eventually triggered the bug. Looks like this is really an existing bug not related to the eventfs, but the eventfs code actually opened up the window of this race.
Hopefully I'll have a fix shortly.
-- Steve