On Mon, 5 Feb 2018 10:00:50 -0500 Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > On Mon, 5 Feb 2018 09:24:23 +0100 > Jiri Olsa <jolsa@xxxxxxxxxx> wrote: > > > > should this be done under 'func_event_mutex' ? > > Probably. I think we only need to add the list. > > > > > I tried and crashed the system by running 2 scripts with: > > > > echo 'ip_rcv(u64 skb, u64 dev)' > /sys/kernel/debug/tracing/function_events > > echo 'SyS_openat(int dfd, string buf, x32 flags, x32 mode)' >> /sys/kernel/debug/tracing/function_events > > echo 'SyS_open(x8[32] buf, x32 flags, x32 mode)' >> /sys/kernel/debug/tracing/function_events > > > There's no reason that we can't have more than one function event attached to the same function. I'm adding this: diff --git a/kernel/trace/trace_event_ftrace.c b/kernel/trace/trace_event_ftrace.c index b145639eac45..928168fc2025 100644 --- a/kernel/trace/trace_event_ftrace.c +++ b/kernel/trace/trace_event_ftrace.c @@ -1275,12 +1275,6 @@ static int create_function_event(int argc, char **argv) if (state != FUNC_STATE_END) goto fail; - ret = -EALREADY; - list_for_each_entry(fe, &func_events, list) { - if (strcmp(fe->func, func_event->func) == 0) - goto fail; - } - ret = ftrace_set_filter(&func_event->ops, func_event->func, strlen(func_event->func), 0); if (ret < 0) @@ -1290,7 +1284,9 @@ static int create_function_event(int argc, char **argv) if (ret < 0) goto fail; + mutex_lock(&func_event_mutex); list_add_tail(&func_event->list, &func_events); + mutex_unlock(&func_event_mutex); return 0; fail: free_func_event(func_event); -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-trace-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html