From c61f1fd27e19d6614dcb381b4d8e7bac0429e412 Mon Sep 17 00:00:00 2001
From: Joern Engel <joern@logfs.org>
Date: Thu, 2 Apr 2015 15:19:57 -0700
Subject: [PATCH] net: Check for neighbor refcount bugs
Debugging why we crash in the timer softirq without this is pretty
painful. Should be low-overhead and give a more meaningful backtrace.
Signed-off-by: Joern Engel <joern@logfs.org>
---
include/net/neighbour.h | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
@@ -297,8 +297,10 @@ static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
static inline void neigh_release(struct neighbour *neigh)
{
- if (atomic_dec_and_test(&neigh->refcnt))
+ if (atomic_dec_and_test(&neigh->refcnt)) {
+ WARN_ON_ONCE(timer_pending(&neigh->timer));
neigh_destroy(neigh);
+ }
}
static inline struct neighbour * neigh_clone(struct neighbour *neigh)
@@ -308,7 +310,10 @@ static inline struct neighbour * neigh_clone(struct neighbour *neigh)
return neigh;
}
-#define neigh_hold(n) atomic_inc(&(n)->refcnt)
+static inline void neigh_hold(struct neighbour *neigh)
+{
+ WARN_ON_ONCE(atomic_inc_return(&neigh->refcnt) == 1);
+}
static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
{
--
2.1.4