# modprobe trace-events-sample
# echo 1 > /sys/kernel/debug/tracing/events/sample-trace/enable
# rmmod trace-events-sample
This would cause an oops. The issue is that I added another trace
event sample that reused a reg function of another trace event to
create a thread to call the tracepoints. The problem was that the
reg function couldn't handle nested calls (reg; reg; unreg; unreg;)
and created two threads (instead of one) and only removed one
on exit.
This isn't a critical bug as the bug is only in sample code. But sample
code should be free of known bugs to prevent others from copying
it. This is why this is also marked for stable.
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Merge tag 'trace-v4.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fix from Steven Rostedt:
"Testing a new trace event format, I triggered a bug by doing:
# modprobe trace-events-sample
# echo 1 > /sys/kernel/debug/tracing/events/sample-trace/enable
# rmmod trace-events-sample
This would cause an oops. The issue is that I added another trace
event sample that reused a reg function of another trace event to
create a thread to call the tracepoints. The problem was that the reg
function couldn't handle nested calls (reg; reg; unreg; unreg;) and
created two threads (instead of one) and only removed one on exit.
This isn't a critical bug as the bug is only in sample code. But
sample code should be free of known bugs to prevent others from
copying it. This is why this is also marked for stable"
* tag 'trace-v4.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing/samples: Fix creation and deletion of simple_thread_fn creation
503f7e297d