From 0fbcae222b8aa3a47034a484e02e7fc14050c783 Mon Sep 17 00:00:00 2001
From: Julia Lawall <julia@diku.dk>
Date: Wed, 10 Mar 2010 15:23:52 -0800
Subject: [PATCH] drivers/char/mmtimer.c: eliminate useless code
The variable x is initialized twice to the same (side effect-free)
expression. Drop one initialization.
A simplified version of the semantic match that finds this problem is:
(http://coccinelle.lip6.fr/)
// <smpl>
@forall@
idexpression *x;
identifier f!=ERR_PTR;
@@
x = f(...)
... when != x
(
x = f(...,<+...x...+>,...)
|
* x = f(...)
)
// </smpl>
Stefan observed:
The next x = rb_entry(mn->next, struct mmtimer, list); is preceded by a
test whether mn->next is NULL.
Unless that test is redundant too, your patch fixes a potential NULL
pointer dereference, introduced by commit cbacdd95 "SGI Altix mmtimer:
allow larger number of timers per node" in 2.6.26.
Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
drivers/char/mmtimer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/char/mmtimer.c b/drivers/char/mmtimer.c
index 918711aa56f3c..04fd0d843b3b2 100644
--- a/drivers/char/mmtimer.c
+++ b/drivers/char/mmtimer.c
@@ -546,7 +546,7 @@ static void mmtimer_tasklet(unsigned long data)
{
int nodeid = data;
struct mmtimer_node *mn = &timers[nodeid];
- struct mmtimer *x = rb_entry(mn->next, struct mmtimer, list);
+ struct mmtimer *x;
struct k_itimer *t;
unsigned long flags;
--
GitLab