Messages in this thread | | | Date | Thu, 7 Sep 2023 09:01:30 +0800 | Subject | Re: "[PATCH] selftests/ftrace: Correctly enable event in instance-event.tc" | From | Zheng Yejian <> |
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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 >
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