From 93821778def10ec1e69aa3ac10adee975dad4ff3 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Mon, 15 Sep 2008 11:48:46 -0700 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- net/ipv4/udp.c | 62 +++++++++++++++++++++++++++----------------------- 1 file changed, 33 insertions(+), 29 deletions(-) diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 8e42fbbd576..57e26fa6618 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -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, -- 2.41.0