[PATCH 1/3] trace_stat: Fix missing entry in stat file

[Li Zefan <lizf@cn.fujitsu.com>]

One entry is missing in the output of a stat file.

The cause is, when stat_seq_start() is called the 2nd time, we should
start from the (pos-1)th elem in the rbtree but not pos, because
pos == 0 is the header.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
 kernel/trace/trace_stat.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index 07c60b0..a4bb239 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -203,17 +203,21 @@ static void *stat_seq_start(struct seq_file *s, loff_t *pos)
 {
 	struct stat_session *session = s->private;
 	struct rb_node *node;
+	int n = *pos;
 	int i;
 
 	/* Prevent from tracer switch or rbtree modification */
 	mutex_lock(&session->stat_mutex);
 
 	/* If we are in the beginning of the file, print the headers */
-	if (!*pos && session->ts->stat_headers)
-		return SEQ_START_TOKEN;
+	if (session->ts->stat_headers) {
+		if (n == 0)
+			return SEQ_START_TOKEN;
+		n--;
+	}
 
 	node = rb_first(&session->stat_root);
-	for (i = 0; node && i < *pos; i++)
+	for (i = 0; node && i < n; i++)
 		node = rb_next(node);
 
 	return node;
-- 
1.6.3