diff options
| author | Pavel Emelyanov | 2007-10-17 21:22:42 -0700 |
|---|---|---|
| committer | David S. Miller | 2007-10-17 21:22:42 -0700 |
| commit | 47e958eac280c263397582d5581e868c3227a1bd (patch) | |
| tree | 67fc50a26b7861b3330eae7f1874df851c0ef740 | |
| parent | d3904b739928edd83d117f1eb5bfa69f18d6f046 (diff) | |
[NET]: Fix the race between sk_filter_(de|at)tach and sk_clone()
The proposed fix is to delay the reference counter decrement
until the quiescent state pass. This will give sk_clone() a
chance to get the reference on the cloned filter.
Regular sk_filter_uncharge can happen from the sk_free() only
and there's no need in delaying the put - the socket is dead
anyway and is to be release itself.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/net/sock.h | 12 | ||||
| -rw-r--r-- | net/core/filter.c | 23 |
2 files changed, 22 insertions, 13 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index b9cfe125c9e6..43fc3fa50d62 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -905,16 +905,6 @@ static inline int sk_filter(struct sock *sk, struct sk_buff *skb) } /** - * sk_filter_rcu_free: Free a socket filter - * @rcu: rcu_head that contains the sk_filter to free - */ -static inline void sk_filter_rcu_free(struct rcu_head *rcu) -{ - struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu); - kfree(fp); -} - -/** * sk_filter_release: Release a socket filter * @sk: socket * @fp: filter to remove @@ -925,7 +915,7 @@ static inline void sk_filter_rcu_free(struct rcu_head *rcu) static inline void sk_filter_release(struct sk_filter *fp) { if (atomic_dec_and_test(&fp->refcnt)) - call_rcu_bh(&fp->rcu, sk_filter_rcu_free); + kfree(fp); } static inline void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp) diff --git a/net/core/filter.c b/net/core/filter.c index 54dddc92452d..1f0068eae501 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -387,6 +387,25 @@ int sk_chk_filter(struct sock_filter *filter, int flen) } /** + * sk_filter_rcu_release: Release a socket filter by rcu_head + * @rcu: rcu_head that contains the sk_filter to free + */ +static void sk_filter_rcu_release(struct rcu_head *rcu) +{ + struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu); + + sk_filter_release(fp); +} + +static void sk_filter_delayed_uncharge(struct sock *sk, struct sk_filter *fp) +{ + unsigned int size = sk_filter_len(fp); + + atomic_sub(size, &sk->sk_omem_alloc); + call_rcu_bh(&fp->rcu, sk_filter_rcu_release); +} + +/** * sk_attach_filter - attach a socket filter * @fprog: the filter program * @sk: the socket to use @@ -428,7 +447,7 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) rcu_assign_pointer(sk->sk_filter, fp); rcu_read_unlock_bh(); - sk_filter_uncharge(sk, old_fp); + sk_filter_delayed_uncharge(sk, old_fp); return 0; } @@ -441,7 +460,7 @@ int sk_detach_filter(struct sock *sk) filter = rcu_dereference(sk->sk_filter); if (filter) { rcu_assign_pointer(sk->sk_filter, NULL); - sk_filter_uncharge(sk, filter); + sk_filter_delayed_uncharge(sk, filter); ret = 0; } rcu_read_unlock_bh(); |