[PATCH 3/3] tracing: Check cpu file on tracing_release()

[Namhyung Kim <namhyung@kernel.org>]

From: Namhyung Kim <namhyung.kim@lge.com>

It looks like tracing_release() lacks checking iter->cpu_file so that
closing a per_cpu trace file would attempt to close all cpu buffers.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 kernel/trace/trace.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7270460cfe3c..0beddcb80509 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2883,7 +2883,13 @@ static int tracing_release(struct inode *inode, struct file *file)
 	WARN_ON(!tr->ref);
 	tr->ref--;
 
-	for_each_tracing_cpu(cpu) {
+	if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
+		for_each_tracing_cpu(cpu) {
+			if (iter->buffer_iter[cpu])
+				ring_buffer_read_finish(iter->buffer_iter[cpu]);
+		}
+	} else {
+		cpu = iter->cpu_file;
 		if (iter->buffer_iter[cpu])
 			ring_buffer_read_finish(iter->buffer_iter[cpu]);
 	}
-- 
1.7.11.7