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tipc: Revert "tipc: use existing sk_write_queue for outgoing packet chain"

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[ Upstream commit f214fc4029 ]

reverts commit 94153e36e7 ("tipc: use existing sk_write_queue for
outgoing packet chain")

In Commit 94153e36e7, 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Parthasarathy Bhuvaragan
2016-03-01 11:07:09 +01:00
committed by Greg Kroah-Hartman
parent d9bbdcd83d
commit 7da899cee1
1 changed files with 19 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
net/tipc/socket.c
View File

@@ -673,7 +673,7 @@ static int tipc_sendmcast(struct socket *sock, struct tipc_name_seq *seq,
struct tipc_sock *tsk = tipc_sk(sk); struct tipc_sock *tsk = tipc_sk(sk);
struct net *net = sock_net(sk); struct net *net = sock_net(sk);
struct tipc_msg *mhdr = &tsk->phdr; 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; struct iov_iter save = msg->msg_iter;
uint mtu; uint mtu;
int rc; 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_nameupper(mhdr, seq->upper);
msg_set_hdr_sz(mhdr, MCAST_H_SIZE); msg_set_hdr_sz(mhdr, MCAST_H_SIZE);
skb_queue_head_init(&pktchain);
new_mtu: new_mtu:
mtu = tipc_bcast_get_mtu(net); 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)) if (unlikely(rc < 0))
return rc; return rc;
do { do {
rc = tipc_bcast_xmit(net, pktchain); rc = tipc_bcast_xmit(net, &pktchain);
if (likely(!rc)) if (likely(!rc))
return dsz; return dsz;
@@ -704,7 +706,7 @@ new_mtu:
if (!rc) if (!rc)
continue; continue;
} }
__skb_queue_purge(pktchain); __skb_queue_purge(&pktchain);
if (rc == -EMSGSIZE) { if (rc == -EMSGSIZE) {
msg->msg_iter = save; msg->msg_iter = save;
goto new_mtu; 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 net *net = sock_net(sk);
struct tipc_msg *mhdr = &tsk->phdr; struct tipc_msg *mhdr = &tsk->phdr;
u32 dnode, dport; u32 dnode, dport;
struct sk_buff_head *pktchain = &sk->sk_write_queue; struct sk_buff_head pktchain;
struct sk_buff *skb; struct sk_buff *skb;
struct tipc_name_seq *seq; struct tipc_name_seq *seq;
struct iov_iter save; 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); msg_set_hdr_sz(mhdr, BASIC_H_SIZE);
} }
skb_queue_head_init(&pktchain);
save = m->msg_iter; save = m->msg_iter;
new_mtu: new_mtu:
mtu = tipc_node_get_mtu(net, dnode, tsk->portid); 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) if (rc < 0)
return rc; return rc;
do { do {
skb = skb_peek(pktchain); skb = skb_peek(&pktchain);
TIPC_SKB_CB(skb)->wakeup_pending = tsk->link_cong; 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 (likely(!rc)) {
if (sock->state != SS_READY) if (sock->state != SS_READY)
sock->state = SS_CONNECTING; sock->state = SS_CONNECTING;
@@ -946,7 +949,7 @@ new_mtu:
if (!rc) if (!rc)
continue; continue;
} }
__skb_queue_purge(pktchain); __skb_queue_purge(&pktchain);
if (rc == -EMSGSIZE) { if (rc == -EMSGSIZE) {
m->msg_iter = save; m->msg_iter = save;
goto new_mtu; 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 net *net = sock_net(sk);
struct tipc_sock *tsk = tipc_sk(sk); struct tipc_sock *tsk = tipc_sk(sk);
struct tipc_msg *mhdr = &tsk->phdr; 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); DECLARE_SOCKADDR(struct sockaddr_tipc *, dest, m->msg_name);
u32 portid = tsk->portid; u32 portid = tsk->portid;
int rc = -EINVAL; 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); timeo = sock_sndtimeo(sk, m->msg_flags & MSG_DONTWAIT);
dnode = tsk_peer_node(tsk); dnode = tsk_peer_node(tsk);
skb_queue_head_init(&pktchain);
next: next:
save = m->msg_iter; save = m->msg_iter;
mtu = tsk->max_pkt; mtu = tsk->max_pkt;
send = min_t(uint, dsz - sent, TIPC_MAX_USER_MSG_SIZE); 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)) if (unlikely(rc < 0))
return rc; return rc;
do { do {
if (likely(!tsk_conn_cong(tsk))) { 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)) { if (likely(!rc)) {
tsk->sent_unacked++; tsk->sent_unacked++;
sent += send; sent += send;
@@ -1063,7 +1068,7 @@ next:
goto next; goto next;
} }
if (rc == -EMSGSIZE) { if (rc == -EMSGSIZE) {
__skb_queue_purge(pktchain); __skb_queue_purge(&pktchain);
tsk->max_pkt = tipc_node_get_mtu(net, dnode, tsk->max_pkt = tipc_node_get_mtu(net, dnode,
portid); portid);
m->msg_iter = save; m->msg_iter = save;
@@ -1077,7 +1082,7 @@ next:
rc = tipc_wait_for_sndpkt(sock, &timeo); rc = tipc_wait_for_sndpkt(sock, &timeo);
} while (!rc); } while (!rc);
__skb_queue_purge(pktchain); __skb_queue_purge(&pktchain);
return sent ? sent : rc; return sent ? sent : rc;
} }