[tip:tracing/ftrace] tracing: fix leak in event_format_read()

[Tom Zanussi <tzanussi@gmail.com>]

Commit-ID:  c269fc8c537d761f36cb98e637ae934d9331a9d5
Gitweb:     http://git.kernel.org/tip/c269fc8c537d761f36cb98e637ae934d9331a9d5
Author:     Tom Zanussi <tzanussi@gmail.com>
AuthorDate: Tue, 17 Mar 2009 01:20:59 -0500
Commit:     Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 17 Mar 2009 08:38:23 +0100

tracing: fix leak in event_format_read()

Impact: fix memory leak

If event_format_read() exits early due to nonzero ppos, the
previous kmalloc doesn't get freed - might as well do the
check before the kmalloc and avoid the problem.

Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237270859.8033.141.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>


---
 kernel/trace/trace_events.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 238ea95..c88227b 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -378,15 +378,15 @@ event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
 	char *buf;
 	int r;
 
+	if (*ppos)
+		return 0;
+
 	s = kmalloc(sizeof(*s), GFP_KERNEL);
 	if (!s)
 		return -ENOMEM;
 
 	trace_seq_init(s);
 
-	if (*ppos)
-		return 0;
-
 	/* If any of the first writes fail, so will the show_format. */
 
 	trace_seq_printf(s, "name: %s\n", call->name);