Hi Masami, You're right, this is a bug, thanks for sending the patch to fix it. Tom Reviewed-by: Tom Zanussi <zanussi@xxxxxxxxxx> On Wed, 2020-02-12 at 14:54 +0900, Masami Hiramatsu wrote: > When the synthetic event is software disabled, > __synth_event_trace_start() does not allocate an event buffer. > In this case __synth_event_trace_end() also should not commit > the buffer. > > Check the trace_state->disabled at __synth_event_trace_end() > and if it is disabled, skip it. > > Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> > --- > kernel/trace/trace_events_hist.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/kernel/trace/trace_events_hist.c > b/kernel/trace/trace_events_hist.c > index 483b3fd1094f..781e4b55e117 100644 > --- a/kernel/trace/trace_events_hist.c > +++ b/kernel/trace/trace_events_hist.c > @@ -1847,6 +1847,9 @@ __synth_event_trace_start(struct > trace_event_file *file, > static inline void > __synth_event_trace_end(struct synth_event_trace_state *trace_state) > { > + if (trace_state->disabled) > + return; > + > trace_event_buffer_commit(&trace_state->fbuffer); > > ring_buffer_nest_end(trace_state->buffer); >