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From: Lai Jiangshan <laijs@cn.fujitsu.com>
To: Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@elte.hu>,
	LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH] tracing: kill wrong message when cat tracing/trace
Date: Mon, 05 Apr 2010 17:11:05 +0800	[thread overview]
Message-ID: <4BB9A929.2000303@cn.fujitsu.com> (raw)

Because of a local variable is not initialized, I got these
when I did 'cat tracing/trace'. (not trace_pipe):

CPU:0 [LOST 18446744071579453134 EVENTS]
              ps-3099  [000]   560.770221: lock_acquire: ffff880030865010 &(&dentry->d_lock)->rlock
CPU:0 [LOST 18446744071579453134 EVENTS]
              ps-3099  [000]   560.770221: lock_release: ffff880030865010 &(&dentry->d_lock)->rlock
CPU:0 [LOST 18446612133255294080 EVENTS]
              ps-3099  [000]   560.770221: lock_acquire: ffff880030865010 &(&dentry->d_lock)->rlock
CPU:0 [LOST 18446744071579453134 EVENTS]
              ps-3099  [000]   560.770222: lock_release: ffff880030865010 &(&dentry->d_lock)->rlock
CPU:0 [LOST 18446744071579453134 EVENTS]
              ps-3099  [000]   560.770222: lock_release: ffffffff816cfb98 dcache_lock

See peek_next_entry(), it does not set *lost_events when we 'cat tracing/trace'

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 0498beb..b9be232 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1571,7 +1571,7 @@ __find_next_entry(struct trace_iterator *iter, int *ent_cpu,
 {
 	struct ring_buffer *buffer = iter->tr->buffer;
 	struct trace_entry *ent, *next = NULL;
-	unsigned long lost_events, next_lost = 0;
+	unsigned long lost_events = 0, next_lost = 0;
 	int cpu_file = iter->cpu_file;
 	u64 next_ts = 0, ts;
 	int next_cpu = -1;


             reply	other threads:[~2010-04-05  9:11 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-05  9:11 Lai Jiangshan [this message]
2010-04-05 14:52 ` [PATCH] tracing: kill wrong message when cat tracing/trace Steven Rostedt
2010-04-14 15:00 ` [tip:tracing/core] tracing: Fix uninitialized variable of tracing/trace output tip-bot for Lai Jiangshan

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