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>

1 files changed, 3 insertions, 3 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 238ea95a4115..c88227b3b9db 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);