tracing: Check return value of tracing_dentry_percpu()
If tracing_dentry_percpu() failed, tracing_init_debugfs_percpu()
will try to create each cpu directories on debugfs' root directory
as d_percpu is NULL.
Link: http://lkml.kernel.org/r/1335143517-2285-1-git-send-email-namhyung.kim@lge.com
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Namhyung Kim <namhyung.kim@lge.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index dfbd86c..0ed4df0 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4474,6 +4474,9 @@
struct dentry *d_cpu;
char cpu_dir[30]; /* 30 characters should be more than enough */
+ if (!d_percpu)
+ return;
+
snprintf(cpu_dir, 30, "cpu%ld", cpu);
d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
if (!d_cpu) {