From: Steven Rostedt Date: Thu, 10 Jun 2010 18:53:16 +0000 (-0400) Subject: perf/tracing: Fix regression of perf losing kprobe events X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=a8fb2608053547bc3152ea61a5ec7cdfce5d942c;p=openwrt%2Fstaging%2Fblogic.git perf/tracing: Fix regression of perf losing kprobe events With the addition of the code to shrink the kernel tracepoint infrastructure, we lost kprobes being traced by perf. The reason is that I tested if the "tp_event->class->perf_probe" existed before enabling it. This prevents "ftrace only" events (like the function trace events) from being enabled by perf. Unfortunately, kprobe events do not use perf_probe. This causes kprobes to be missed by perf. To fix this, we add the test to see if "tp_event->class->reg" exists as well as perf_probe. Normal trace events have only "perf_probe" but no "reg" function, and kprobes and syscalls have the "reg" but no "perf_probe". The ftrace unique events do not have either, so this is a valid test. If a kprobe or syscall is not to be probed by perf, the "reg" function is called anyway, and will return a failure and prevent perf from probing it. Reported-by: Srikar Dronamraju Tested-by: Srikar Dronamraju Acked-by: Peter Zijlstra Signed-off-by: Steven Rostedt --- diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index e6f65887842c..8a2b73f7c068 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -96,7 +96,9 @@ int perf_trace_init(struct perf_event *p_event) mutex_lock(&event_mutex); list_for_each_entry(tp_event, &ftrace_events, list) { if (tp_event->event.type == event_id && - tp_event->class && tp_event->class->perf_probe && + tp_event->class && + (tp_event->class->perf_probe || + tp_event->class->reg) && try_module_get(tp_event->mod)) { ret = perf_trace_event_init(tp_event, p_event); break;