kernel/trace: Fix do not unregister tracepoints when register sched_migrate_task...

In the function, if register_trace_sched_migrate_task() returns error,
sched_switch/sched_wakeup_new/sched_wakeup won't unregister. That is
why fail_deprobe_sched_switch was added.

Link: http://lkml.kernel.org/r/20191231133530.2794-1-pilgrimtao@gmail.com
Cc: stable@vger.kernel.org
Fixes: 478142c39c8c2 ("tracing: do not grab lock in wakeup latency function tracing")
Signed-off-by: Kaitao Cheng <pilgrimtao@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 5e43b96..617e297 100644 (file)
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -630,7 +630,7 @@ static void start_wakeup_tracer(struct trace_array *tr)
        if (ret) {
                pr_info("wakeup trace: Couldn't activate tracepoint"
                        " probe to kernel_sched_migrate_task\n");
-               return;
+               goto fail_deprobe_sched_switch;
        }
 
        wakeup_reset(tr);
@@ -648,6 +648,8 @@ static void start_wakeup_tracer(struct trace_array *tr)
                printk(KERN_ERR "failed to start wakeup tracer\n");
 
        return;
+fail_deprobe_sched_switch:
+       unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
 fail_deprobe_wake_new:
        unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
 fail_deprobe: