Commit a82274151a "tracing: Protect ftrace_trace_arrays list in trace_events.c"
added taking the trace_types_lock mutex in trace_events.c as there were
several locations that needed it for protection. Unfortunately, it also
encapsulated a call to tracing_reset_all_online_cpus() which also takes
the trace_types_lock, causing a deadlock.
This happens when a module has tracepoints and has been traced. When the
module is removed, the trace events module notifier will grab the
trace_types_lock, do a bunch of clean ups, and also clears the buffer
by calling tracing_reset_all_online_cpus. This doesn't happen often
which explains why it wasn't caught right away.
Commit a82274151a was marked for stable, which means this must be
sent to stable too.
Link: http://lkml.kernel.org/r/[email protected]
Reported-by: Arend van Spril <[email protected]>
Tested-by: Arend van Spriel <[email protected]>
Cc: Alexander Z Lam <[email protected]>
Cc: Vaibhav Nagarnaik <[email protected]>
Cc: David Sharp <[email protected]>
Cc: [email protected] # 3.10
Signed-off-by: Steven Rostedt <[email protected]>
09d8091c02