tracing: Wait for preempt irq delay thread to finish

Running on a slower machine, it is possible that the preempt delay kernel
thread may still be executing if the module was immediately removed after
added, and this can cause the kernel to crash as the kernel thread might be
executing after its code has been removed.

There's no reason that the caller of the code shouldn't just wait for the
delay thread to finish, as the thread can also be created by a trigger in
the sysfs code, which also has the same issues.

Link: http://lore.kernel.org/r/[email protected]

Cc: [email protected]
Fixes: 793937236d1ee ("lib: Add module for testing preemptoff/irqsoff latency tracers")
Reported-by: Xiao Yang <[email protected]>
Reviewed-by: Xiao Yang <[email protected]>
Reviewed-by: Joel Fernandes <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>

0 files changed, 0 insertions, 0 deletions