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| author | Marek Lindner <lindner_marek@yahoo.de> | 2011-02-10 14:33:51 +0000 |
|---|---|---|
| committer | Marek Lindner <lindner_marek@yahoo.de> | 2011-03-05 12:50:07 +0100 |
| commit | ed75ccbe26f4a672a41556120390e67c80a2c441 (patch) | |
| tree | 3f4f844d2311e662b4c42e7a275188d1346ac77d /net/batman-adv/hard-interface.h | |
| parent | 7d2b554826195372764910da2f0dcb0d9b869108 (diff) | |
| download | linux-rt-ed75ccbe26f4a672a41556120390e67c80a2c441.tar.gz | |
batman-adv: Correct rcu refcounting for batman_if
It might be possible that 2 threads access the same data in the same
rcu grace period. The first thread calls call_rcu() to decrement the
refcount and free the data while the second thread increases the
refcount to use the data. To avoid this race condition all refcount
operations have to be atomic.
Reported-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Diffstat (limited to 'net/batman-adv/hard-interface.h')
| -rw-r--r-- | net/batman-adv/hard-interface.h | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/net/batman-adv/hard-interface.h b/net/batman-adv/hard-interface.h index ad195438428a..e488b90b8fea 100644 --- a/net/batman-adv/hard-interface.h +++ b/net/batman-adv/hard-interface.h @@ -37,13 +37,12 @@ void hardif_disable_interface(struct batman_if *batman_if); void hardif_remove_interfaces(void); int hardif_min_mtu(struct net_device *soft_iface); void update_min_mtu(struct net_device *soft_iface); +void hardif_free_rcu(struct rcu_head *rcu); -static inline void hardif_free_ref(struct kref *refcount) +static inline void hardif_free_ref(struct batman_if *batman_if) { - struct batman_if *batman_if; - - batman_if = container_of(refcount, struct batman_if, refcount); - kfree(batman_if); + if (atomic_dec_and_test(&batman_if->refcount)) + call_rcu(&batman_if->rcu, hardif_free_rcu); } #endif /* _NET_BATMAN_ADV_HARD_INTERFACE_H_ */ |