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authorParthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>2016-03-01 11:07:09 +0100
committerDavid S. Miller <davem@davemloft.net>2016-03-03 16:30:29 -0500
commitf214fc402967e1bc94ad7f39faa03db5813d6849 (patch)
tree5d2ed4587e08c100519da814d6e4af9e11052cb4 /net
parent1837b2e2bcd23137766555a63867e649c0b637f0 (diff)
tipc: Revert "tipc: use existing sk_write_queue for outgoing packet chain"
reverts commit 94153e36e709e ("tipc: use existing sk_write_queue for outgoing packet chain") In Commit 94153e36e709e, we assume that we fill & empty the socket's sk_write_queue within the same lock_sock() session. This is not true if the link is congested. During congestion, the socket lock is released while we wait for the congestion to cease. This implementation causes a nullptr exception, if the user space program has several threads accessing the same socket descriptor. Consider two threads of the same program performing the following: Thread1 Thread2 -------------------- ---------------------- Enter tipc_sendmsg() Enter tipc_sendmsg() lock_sock() lock_sock() Enter tipc_link_xmit(), ret=ELINKCONG spin on socket lock.. sk_wait_event() : release_sock() grab socket lock : Enter tipc_link_xmit(), ret=0 : release_sock() Wakeup after congestion lock_sock() skb = skb_peek(pktchain); !! TIPC_SKB_CB(skb)->wakeup_pending = tsk->link_cong; In this case, the second thread transmits the buffers belonging to both thread1 and thread2 successfully. When the first thread wakeup after the congestion it assumes that the pktchain is intact and operates on the skb's in it, which leads to the following exception: [2102.439969] BUG: unable to handle kernel NULL pointer dereference at 00000000000000d0 [2102.440074] IP: [<ffffffffa005f330>] __tipc_link_xmit+0x2b0/0x4d0 [tipc] [2102.440074] PGD 3fa3f067 PUD 3fa6b067 PMD 0 [2102.440074] Oops: 0000 [#1] SMP [2102.440074] CPU: 2 PID: 244 Comm: sender Not tainted 3.12.28 #1 [2102.440074] RIP: 0010:[<ffffffffa005f330>] [<ffffffffa005f330>] __tipc_link_xmit+0x2b0/0x4d0 [tipc] [...] [2102.440074] Call Trace: [2102.440074] [<ffffffff8163f0b9>] ? schedule+0x29/0x70 [2102.440074] [<ffffffffa006a756>] ? tipc_node_unlock+0x46/0x170 [tipc] [2102.440074] [<ffffffffa005f761>] tipc_link_xmit+0x51/0xf0 [tipc] [2102.440074] [<ffffffffa006d8ae>] tipc_send_stream+0x11e/0x4f0 [tipc] [2102.440074] [<ffffffff8106b150>] ? __wake_up_sync+0x20/0x20 [2102.440074] [<ffffffffa006dc9c>] tipc_send_packet+0x1c/0x20 [tipc] [2102.440074] [<ffffffff81502478>] sock_sendmsg+0xa8/0xd0 [2102.440074] [<ffffffff81507895>] ? release_sock+0x145/0x170 [2102.440074] [<ffffffff815030d8>] ___sys_sendmsg+0x3d8/0x3e0 [2102.440074] [<ffffffff816426ae>] ? _raw_spin_unlock+0xe/0x10 [2102.440074] [<ffffffff81115c2a>] ? handle_mm_fault+0x6ca/0x9d0 [2102.440074] [<ffffffff8107dd65>] ? set_next_entity+0x85/0xa0 [2102.440074] [<ffffffff816426de>] ? _raw_spin_unlock_irq+0xe/0x20 [2102.440074] [<ffffffff8107463c>] ? finish_task_switch+0x5c/0xc0 [2102.440074] [<ffffffff8163ea8c>] ? __schedule+0x34c/0x950 [2102.440074] [<ffffffff81504e12>] __sys_sendmsg+0x42/0x80 [2102.440074] [<ffffffff81504e62>] SyS_sendmsg+0x12/0x20 [2102.440074] [<ffffffff8164aed2>] system_call_fastpath+0x16/0x1b In this commit, we maintain the skb list always in the stack. Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Acked-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/tipc/socket.c33
1 files changed, 19 insertions, 14 deletions
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 69c29050f14a..4d420bb27396 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -673,7 +673,7 @@ static int tipc_sendmcast(struct socket *sock, struct tipc_name_seq *seq,
struct tipc_sock *tsk = tipc_sk(sk);
struct net *net = sock_net(sk);
struct tipc_msg *mhdr = &tsk->phdr;
- struct sk_buff_head *pktchain = &sk->sk_write_queue;
+ struct sk_buff_head pktchain;
struct iov_iter save = msg->msg_iter;
uint mtu;
int rc;
@@ -687,14 +687,16 @@ static int tipc_sendmcast(struct socket *sock, struct tipc_name_seq *seq,
msg_set_nameupper(mhdr, seq->upper);
msg_set_hdr_sz(mhdr, MCAST_H_SIZE);
+ skb_queue_head_init(&pktchain);
+
new_mtu:
mtu = tipc_bcast_get_mtu(net);
- rc = tipc_msg_build(mhdr, msg, 0, dsz, mtu, pktchain);
+ rc = tipc_msg_build(mhdr, msg, 0, dsz, mtu, &pktchain);
if (unlikely(rc < 0))
return rc;
do {
- rc = tipc_bcast_xmit(net, pktchain);
+ rc = tipc_bcast_xmit(net, &pktchain);
if (likely(!rc))
return dsz;
@@ -704,7 +706,7 @@ new_mtu:
if (!rc)
continue;
}
- __skb_queue_purge(pktchain);
+ __skb_queue_purge(&pktchain);
if (rc == -EMSGSIZE) {
msg->msg_iter = save;
goto new_mtu;
@@ -863,7 +865,7 @@ static int __tipc_sendmsg(struct socket *sock, struct msghdr *m, size_t dsz)
struct net *net = sock_net(sk);
struct tipc_msg *mhdr = &tsk->phdr;
u32 dnode, dport;
- struct sk_buff_head *pktchain = &sk->sk_write_queue;
+ struct sk_buff_head pktchain;
struct sk_buff *skb;
struct tipc_name_seq *seq;
struct iov_iter save;
@@ -924,17 +926,18 @@ static int __tipc_sendmsg(struct socket *sock, struct msghdr *m, size_t dsz)
msg_set_hdr_sz(mhdr, BASIC_H_SIZE);
}
+ skb_queue_head_init(&pktchain);
save = m->msg_iter;
new_mtu:
mtu = tipc_node_get_mtu(net, dnode, tsk->portid);
- rc = tipc_msg_build(mhdr, m, 0, dsz, mtu, pktchain);
+ rc = tipc_msg_build(mhdr, m, 0, dsz, mtu, &pktchain);
if (rc < 0)
return rc;
do {
- skb = skb_peek(pktchain);
+ skb = skb_peek(&pktchain);
TIPC_SKB_CB(skb)->wakeup_pending = tsk->link_cong;
- rc = tipc_node_xmit(net, pktchain, dnode, tsk->portid);
+ rc = tipc_node_xmit(net, &pktchain, dnode, tsk->portid);
if (likely(!rc)) {
if (sock->state != SS_READY)
sock->state = SS_CONNECTING;
@@ -946,7 +949,7 @@ new_mtu:
if (!rc)
continue;
}
- __skb_queue_purge(pktchain);
+ __skb_queue_purge(&pktchain);
if (rc == -EMSGSIZE) {
m->msg_iter = save;
goto new_mtu;
@@ -1016,7 +1019,7 @@ static int __tipc_send_stream(struct socket *sock, struct msghdr *m, size_t dsz)
struct net *net = sock_net(sk);
struct tipc_sock *tsk = tipc_sk(sk);
struct tipc_msg *mhdr = &tsk->phdr;
- struct sk_buff_head *pktchain = &sk->sk_write_queue;
+ struct sk_buff_head pktchain;
DECLARE_SOCKADDR(struct sockaddr_tipc *, dest, m->msg_name);
u32 portid = tsk->portid;
int rc = -EINVAL;
@@ -1044,17 +1047,19 @@ static int __tipc_send_stream(struct socket *sock, struct msghdr *m, size_t dsz)
timeo = sock_sndtimeo(sk, m->msg_flags & MSG_DONTWAIT);
dnode = tsk_peer_node(tsk);
+ skb_queue_head_init(&pktchain);
next:
save = m->msg_iter;
mtu = tsk->max_pkt;
send = min_t(uint, dsz - sent, TIPC_MAX_USER_MSG_SIZE);
- rc = tipc_msg_build(mhdr, m, sent, send, mtu, pktchain);
+ rc = tipc_msg_build(mhdr, m, sent, send, mtu, &pktchain);
if (unlikely(rc < 0))
return rc;
+
do {
if (likely(!tsk_conn_cong(tsk))) {
- rc = tipc_node_xmit(net, pktchain, dnode, portid);
+ rc = tipc_node_xmit(net, &pktchain, dnode, portid);
if (likely(!rc)) {
tsk->sent_unacked++;
sent += send;
@@ -1063,7 +1068,7 @@ next:
goto next;
}
if (rc == -EMSGSIZE) {
- __skb_queue_purge(pktchain);
+ __skb_queue_purge(&pktchain);
tsk->max_pkt = tipc_node_get_mtu(net, dnode,
portid);
m->msg_iter = save;
@@ -1077,7 +1082,7 @@ next:
rc = tipc_wait_for_sndpkt(sock, &timeo);
} while (!rc);
- __skb_queue_purge(pktchain);
+ __skb_queue_purge(&pktchain);
return sent ? sent : rc;
}