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udp: Fix rcv socket locking 

The previous patch in response to the recursive locking on IPsec
reception is broken as it tries to drop the BH socket lock while in
user context.

This patch fixes it by shrinking the section protected by the
socket lock to sock_queue_rcv_skb only.  The only reason we added
the lock is for the accounting which happens in that function.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Herbert Xu 2008-09-15 11:48:46 -07:00 committed by David S. Miller
parent cff502a383
commit 93821778de
1 changed files with 33 additions and 29 deletions
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62
net/ipv4/udp.c
View File

@ -951,6 +951,27 @@ int udp_disconnect(struct sock *sk, int flags)
return 0;
}
static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
int is_udplite = IS_UDPLITE(sk);
int rc;
if ((rc = sock_queue_rcv_skb(sk, skb)) < 0) {
/* Note that an ENOMEM error is charged twice */
if (rc == -ENOMEM)
UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
is_udplite);
goto drop;
}
return 0;
drop:
UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
kfree_skb(skb);
return -1;
}
/* returns:
* -1: error
* 0: success
@ -989,9 +1010,7 @@ int udp_queue_rcv_skb(struct sock * sk, struct sk_buff *skb)
up->encap_rcv != NULL) {
int ret;
bh_unlock_sock(sk);
ret = (*up->encap_rcv)(sk, skb);
bh_lock_sock(sk);
if (ret <= 0) {
UDP_INC_STATS_BH(sock_net(sk),
UDP_MIB_INDATAGRAMS,
@ -1044,17 +1063,16 @@ int udp_queue_rcv_skb(struct sock * sk, struct sk_buff *skb)
goto drop;
}
if ((rc = sock_queue_rcv_skb(sk,skb)) < 0) {
/* Note that an ENOMEM error is charged twice */
if (rc == -ENOMEM) {
UDP_INC_STATS_BH(sock_net(sk),
UDP_MIB_RCVBUFERRORS, is_udplite);
atomic_inc(&sk->sk_drops);
}
goto drop;
}
rc = 0;
return 0;
bh_lock_sock(sk);
if (!sock_owned_by_user(sk))
rc = __udp_queue_rcv_skb(sk, skb);
else
sk_add_backlog(sk, skb);
bh_unlock_sock(sk);
return rc;
drop:
UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
@ -1092,15 +1110,7 @@ static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
skb1 = skb_clone(skb, GFP_ATOMIC);
if (skb1) {
int ret = 0;
bh_lock_sock(sk);
if (!sock_owned_by_user(sk))
ret = udp_queue_rcv_skb(sk, skb1);
else
sk_add_backlog(sk, skb1);
bh_unlock_sock(sk);
int ret = udp_queue_rcv_skb(sk, skb1);
if (ret > 0)
/* we should probably re-process instead
* of dropping packets here. */
@ -1195,13 +1205,7 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct hlist_head udptable[],
uh->dest, inet_iif(skb), udptable);
if (sk != NULL) {
int ret = 0;
bh_lock_sock(sk);
if (!sock_owned_by_user(sk))
ret = udp_queue_rcv_skb(sk, skb);
else
sk_add_backlog(sk, skb);
bh_unlock_sock(sk);
int ret = udp_queue_rcv_skb(sk, skb);
sock_put(sk);
/* a return value > 0 means to resubmit the input, but
@ -1494,7 +1498,7 @@ struct proto udp_prot = {
.sendmsg = udp_sendmsg,
.recvmsg = udp_recvmsg,
.sendpage = udp_sendpage,
.backlog_rcv = udp_queue_rcv_skb,
.backlog_rcv = __udp_queue_rcv_skb,
.hash = udp_lib_hash,
.unhash = udp_lib_unhash,
.get_port = udp_v4_get_port,