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authorEric Dumazet <edumazet@google.com>2013-10-10 06:30:09 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-11-04 04:31:02 -0800
commita41536775e712e7b438400f73e927ffe4b21149c (patch)
tree811139e04973baf732a05d176e3b13033a26ed46 /net
parenta77db44038f976c2734fb3d2b1ed0cb9c3afde75 (diff)
downloadvexpress-lsk-a41536775e712e7b438400f73e927ffe4b21149c.tar.gz
l2tp: must disable bh before calling l2tp_xmit_skb()
[ Upstream commit 455cc32bf128e114455d11ad919321ab89a2c312 ] François Cachereul made a very nice bug report and suspected the bh_lock_sock() / bh_unlok_sock() pair used in l2tp_xmit_skb() from process context was not good. This problem was added by commit 6af88da14ee284aaad6e4326da09a89191ab6165 ("l2tp: Fix locking in l2tp_core.c"). l2tp_eth_dev_xmit() runs from BH context, so we must disable BH from other l2tp_xmit_skb() users. [ 452.060011] BUG: soft lockup - CPU#1 stuck for 23s! [accel-pppd:6662] [ 452.061757] Modules linked in: l2tp_ppp l2tp_netlink l2tp_core pppoe pppox ppp_generic slhc ipv6 ext3 mbcache jbd virtio_balloon xfs exportfs dm_mod virtio_blk ata_generic virtio_net floppy ata_piix libata virtio_pci virtio_ring virtio [last unloaded: scsi_wait_scan] [ 452.064012] CPU 1 [ 452.080015] BUG: soft lockup - CPU#2 stuck for 23s! [accel-pppd:6643] [ 452.080015] CPU 2 [ 452.080015] [ 452.080015] Pid: 6643, comm: accel-pppd Not tainted 3.2.46.mini #1 Bochs Bochs [ 452.080015] RIP: 0010:[<ffffffff81059f6c>] [<ffffffff81059f6c>] do_raw_spin_lock+0x17/0x1f [ 452.080015] RSP: 0018:ffff88007125fc18 EFLAGS: 00000293 [ 452.080015] RAX: 000000000000aba9 RBX: ffffffff811d0703 RCX: 0000000000000000 [ 452.080015] RDX: 00000000000000ab RSI: ffff8800711f6896 RDI: ffff8800745c8110 [ 452.080015] RBP: ffff88007125fc18 R08: 0000000000000020 R09: 0000000000000000 [ 452.080015] R10: 0000000000000000 R11: 0000000000000280 R12: 0000000000000286 [ 452.080015] R13: 0000000000000020 R14: 0000000000000240 R15: 0000000000000000 [ 452.080015] FS: 00007fdc0cc24700(0000) GS:ffff8800b6f00000(0000) knlGS:0000000000000000 [ 452.080015] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 452.080015] CR2: 00007fdb054899b8 CR3: 0000000074404000 CR4: 00000000000006a0 [ 452.080015] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 452.080015] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 452.080015] Process accel-pppd (pid: 6643, threadinfo ffff88007125e000, task ffff8800b27e6dd0) [ 452.080015] Stack: [ 452.080015] ffff88007125fc28 ffffffff81256559 ffff88007125fc98 ffffffffa01b2bd1 [ 452.080015] ffff88007125fc58 000000000000000c 00000000029490d0 0000009c71dbe25e [ 452.080015] 000000000000005c 000000080000000e 0000000000000000 ffff880071170600 [ 452.080015] Call Trace: [ 452.080015] [<ffffffff81256559>] _raw_spin_lock+0xe/0x10 [ 452.080015] [<ffffffffa01b2bd1>] l2tp_xmit_skb+0x189/0x4ac [l2tp_core] [ 452.080015] [<ffffffffa01c2d36>] pppol2tp_sendmsg+0x15e/0x19c [l2tp_ppp] [ 452.080015] [<ffffffff811c7872>] __sock_sendmsg_nosec+0x22/0x24 [ 452.080015] [<ffffffff811c83bd>] sock_sendmsg+0xa1/0xb6 [ 452.080015] [<ffffffff81254e88>] ? __schedule+0x5c1/0x616 [ 452.080015] [<ffffffff8103c7c6>] ? __dequeue_signal+0xb7/0x10c [ 452.080015] [<ffffffff810bbd21>] ? fget_light+0x75/0x89 [ 452.080015] [<ffffffff811c8444>] ? sockfd_lookup_light+0x20/0x56 [ 452.080015] [<ffffffff811c9b34>] sys_sendto+0x10c/0x13b [ 452.080015] [<ffffffff8125cac2>] system_call_fastpath+0x16/0x1b [ 452.080015] Code: 81 48 89 e5 72 0c 31 c0 48 81 ff 45 66 25 81 0f 92 c0 5d c3 55 b8 00 01 00 00 48 89 e5 f0 66 0f c1 07 0f b6 d4 38 d0 74 06 f3 90 <8a> 07 eb f6 5d c3 90 90 55 48 89 e5 9c 58 0f 1f 44 00 00 5d c3 [ 452.080015] Call Trace: [ 452.080015] [<ffffffff81256559>] _raw_spin_lock+0xe/0x10 [ 452.080015] [<ffffffffa01b2bd1>] l2tp_xmit_skb+0x189/0x4ac [l2tp_core] [ 452.080015] [<ffffffffa01c2d36>] pppol2tp_sendmsg+0x15e/0x19c [l2tp_ppp] [ 452.080015] [<ffffffff811c7872>] __sock_sendmsg_nosec+0x22/0x24 [ 452.080015] [<ffffffff811c83bd>] sock_sendmsg+0xa1/0xb6 [ 452.080015] [<ffffffff81254e88>] ? __schedule+0x5c1/0x616 [ 452.080015] [<ffffffff8103c7c6>] ? __dequeue_signal+0xb7/0x10c [ 452.080015] [<ffffffff810bbd21>] ? fget_light+0x75/0x89 [ 452.080015] [<ffffffff811c8444>] ? sockfd_lookup_light+0x20/0x56 [ 452.080015] [<ffffffff811c9b34>] sys_sendto+0x10c/0x13b [ 452.080015] [<ffffffff8125cac2>] system_call_fastpath+0x16/0x1b [ 452.064012] [ 452.064012] Pid: 6662, comm: accel-pppd Not tainted 3.2.46.mini #1 Bochs Bochs [ 452.064012] RIP: 0010:[<ffffffff81059f6e>] [<ffffffff81059f6e>] do_raw_spin_lock+0x19/0x1f [ 452.064012] RSP: 0018:ffff8800b6e83ba0 EFLAGS: 00000297 [ 452.064012] RAX: 000000000000aaa9 RBX: ffff8800b6e83b40 RCX: 0000000000000002 [ 452.064012] RDX: 00000000000000aa RSI: 000000000000000a RDI: ffff8800745c8110 [ 452.064012] RBP: ffff8800b6e83ba0 R08: 000000000000c802 R09: 000000000000001c [ 452.064012] R10: ffff880071096c4e R11: 0000000000000006 R12: ffff8800b6e83b18 [ 452.064012] R13: ffffffff8125d51e R14: ffff8800b6e83ba0 R15: ffff880072a589c0 [ 452.064012] FS: 00007fdc0b81e700(0000) GS:ffff8800b6e80000(0000) knlGS:0000000000000000 [ 452.064012] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 452.064012] CR2: 0000000000625208 CR3: 0000000074404000 CR4: 00000000000006a0 [ 452.064012] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 452.064012] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 452.064012] Process accel-pppd (pid: 6662, threadinfo ffff88007129a000, task ffff8800744f7410) [ 452.064012] Stack: [ 452.064012] ffff8800b6e83bb0 ffffffff81256559 ffff8800b6e83bc0 ffffffff8121c64a [ 452.064012] ffff8800b6e83bf0 ffffffff8121ec7a ffff880072a589c0 ffff880071096c62 [ 452.064012] 0000000000000011 ffffffff81430024 ffff8800b6e83c80 ffffffff8121f276 [ 452.064012] Call Trace: [ 452.064012] <IRQ> [ 452.064012] [<ffffffff81256559>] _raw_spin_lock+0xe/0x10 [ 452.064012] [<ffffffff8121c64a>] spin_lock+0x9/0xb [ 452.064012] [<ffffffff8121ec7a>] udp_queue_rcv_skb+0x186/0x269 [ 452.064012] [<ffffffff8121f276>] __udp4_lib_rcv+0x297/0x4ae [ 452.064012] [<ffffffff8121c178>] ? raw_rcv+0xe9/0xf0 [ 452.064012] [<ffffffff8121f4a7>] udp_rcv+0x1a/0x1c [ 452.064012] [<ffffffff811fe385>] ip_local_deliver_finish+0x12b/0x1a5 [ 452.064012] [<ffffffff811fe54e>] ip_local_deliver+0x53/0x84 [ 452.064012] [<ffffffff811fe1d0>] ip_rcv_finish+0x2bc/0x2f3 [ 452.064012] [<ffffffff811fe78f>] ip_rcv+0x210/0x269 [ 452.064012] [<ffffffff8101911e>] ? kvm_clock_get_cycles+0x9/0xb [ 452.064012] [<ffffffff811d88cd>] __netif_receive_skb+0x3a5/0x3f7 [ 452.064012] [<ffffffff811d8eba>] netif_receive_skb+0x57/0x5e [ 452.064012] [<ffffffff811cf30f>] ? __netdev_alloc_skb+0x1f/0x3b [ 452.064012] [<ffffffffa0049126>] virtnet_poll+0x4ba/0x5a4 [virtio_net] [ 452.064012] [<ffffffff811d9417>] net_rx_action+0x73/0x184 [ 452.064012] [<ffffffffa01b2cc2>] ? l2tp_xmit_skb+0x27a/0x4ac [l2tp_core] [ 452.064012] [<ffffffff810343b9>] __do_softirq+0xc3/0x1a8 [ 452.064012] [<ffffffff81013b56>] ? ack_APIC_irq+0x10/0x12 [ 452.064012] [<ffffffff81256559>] ? _raw_spin_lock+0xe/0x10 [ 452.064012] [<ffffffff8125e0ac>] call_softirq+0x1c/0x26 [ 452.064012] [<ffffffff81003587>] do_softirq+0x45/0x82 [ 452.064012] [<ffffffff81034667>] irq_exit+0x42/0x9c [ 452.064012] [<ffffffff8125e146>] do_IRQ+0x8e/0xa5 [ 452.064012] [<ffffffff8125676e>] common_interrupt+0x6e/0x6e [ 452.064012] <EOI> [ 452.064012] [<ffffffff810b82a1>] ? kfree+0x8a/0xa3 [ 452.064012] [<ffffffffa01b2cc2>] ? l2tp_xmit_skb+0x27a/0x4ac [l2tp_core] [ 452.064012] [<ffffffffa01b2c25>] ? l2tp_xmit_skb+0x1dd/0x4ac [l2tp_core] [ 452.064012] [<ffffffffa01c2d36>] pppol2tp_sendmsg+0x15e/0x19c [l2tp_ppp] [ 452.064012] [<ffffffff811c7872>] __sock_sendmsg_nosec+0x22/0x24 [ 452.064012] [<ffffffff811c83bd>] sock_sendmsg+0xa1/0xb6 [ 452.064012] [<ffffffff81254e88>] ? __schedule+0x5c1/0x616 [ 452.064012] [<ffffffff8103c7c6>] ? __dequeue_signal+0xb7/0x10c [ 452.064012] [<ffffffff810bbd21>] ? fget_light+0x75/0x89 [ 452.064012] [<ffffffff811c8444>] ? sockfd_lookup_light+0x20/0x56 [ 452.064012] [<ffffffff811c9b34>] sys_sendto+0x10c/0x13b [ 452.064012] [<ffffffff8125cac2>] system_call_fastpath+0x16/0x1b [ 452.064012] Code: 89 e5 72 0c 31 c0 48 81 ff 45 66 25 81 0f 92 c0 5d c3 55 b8 00 01 00 00 48 89 e5 f0 66 0f c1 07 0f b6 d4 38 d0 74 06 f3 90 8a 07 <eb> f6 5d c3 90 90 55 48 89 e5 9c 58 0f 1f 44 00 00 5d c3 55 48 [ 452.064012] Call Trace: [ 452.064012] <IRQ> [<ffffffff81256559>] _raw_spin_lock+0xe/0x10 [ 452.064012] [<ffffffff8121c64a>] spin_lock+0x9/0xb [ 452.064012] [<ffffffff8121ec7a>] udp_queue_rcv_skb+0x186/0x269 [ 452.064012] [<ffffffff8121f276>] __udp4_lib_rcv+0x297/0x4ae [ 452.064012] [<ffffffff8121c178>] ? raw_rcv+0xe9/0xf0 [ 452.064012] [<ffffffff8121f4a7>] udp_rcv+0x1a/0x1c [ 452.064012] [<ffffffff811fe385>] ip_local_deliver_finish+0x12b/0x1a5 [ 452.064012] [<ffffffff811fe54e>] ip_local_deliver+0x53/0x84 [ 452.064012] [<ffffffff811fe1d0>] ip_rcv_finish+0x2bc/0x2f3 [ 452.064012] [<ffffffff811fe78f>] ip_rcv+0x210/0x269 [ 452.064012] [<ffffffff8101911e>] ? kvm_clock_get_cycles+0x9/0xb [ 452.064012] [<ffffffff811d88cd>] __netif_receive_skb+0x3a5/0x3f7 [ 452.064012] [<ffffffff811d8eba>] netif_receive_skb+0x57/0x5e [ 452.064012] [<ffffffff811cf30f>] ? __netdev_alloc_skb+0x1f/0x3b [ 452.064012] [<ffffffffa0049126>] virtnet_poll+0x4ba/0x5a4 [virtio_net] [ 452.064012] [<ffffffff811d9417>] net_rx_action+0x73/0x184 [ 452.064012] [<ffffffffa01b2cc2>] ? l2tp_xmit_skb+0x27a/0x4ac [l2tp_core] [ 452.064012] [<ffffffff810343b9>] __do_softirq+0xc3/0x1a8 [ 452.064012] [<ffffffff81013b56>] ? ack_APIC_irq+0x10/0x12 [ 452.064012] [<ffffffff81256559>] ? _raw_spin_lock+0xe/0x10 [ 452.064012] [<ffffffff8125e0ac>] call_softirq+0x1c/0x26 [ 452.064012] [<ffffffff81003587>] do_softirq+0x45/0x82 [ 452.064012] [<ffffffff81034667>] irq_exit+0x42/0x9c [ 452.064012] [<ffffffff8125e146>] do_IRQ+0x8e/0xa5 [ 452.064012] [<ffffffff8125676e>] common_interrupt+0x6e/0x6e [ 452.064012] <EOI> [<ffffffff810b82a1>] ? kfree+0x8a/0xa3 [ 452.064012] [<ffffffffa01b2cc2>] ? l2tp_xmit_skb+0x27a/0x4ac [l2tp_core] [ 452.064012] [<ffffffffa01b2c25>] ? l2tp_xmit_skb+0x1dd/0x4ac [l2tp_core] [ 452.064012] [<ffffffffa01c2d36>] pppol2tp_sendmsg+0x15e/0x19c [l2tp_ppp] [ 452.064012] [<ffffffff811c7872>] __sock_sendmsg_nosec+0x22/0x24 [ 452.064012] [<ffffffff811c83bd>] sock_sendmsg+0xa1/0xb6 [ 452.064012] [<ffffffff81254e88>] ? __schedule+0x5c1/0x616 [ 452.064012] [<ffffffff8103c7c6>] ? __dequeue_signal+0xb7/0x10c [ 452.064012] [<ffffffff810bbd21>] ? fget_light+0x75/0x89 [ 452.064012] [<ffffffff811c8444>] ? sockfd_lookup_light+0x20/0x56 [ 452.064012] [<ffffffff811c9b34>] sys_sendto+0x10c/0x13b [ 452.064012] [<ffffffff8125cac2>] system_call_fastpath+0x16/0x1b Reported-by: François Cachereul <f.cachereul@alphalink.fr> Tested-by: François Cachereul <f.cachereul@alphalink.fr> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: James Chapman <jchapman@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r--net/l2tp/l2tp_ppp.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 5ebee2ded9e..8c46b271064 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -353,7 +353,9 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh
goto error_put_sess_tun;
}
+ local_bh_disable();
l2tp_xmit_skb(session, skb, session->hdr_len);
+ local_bh_enable();
sock_put(ps->tunnel_sock);
sock_put(sk);
@@ -422,7 +424,9 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
skb->data[0] = ppph[0];
skb->data[1] = ppph[1];
+ local_bh_disable();
l2tp_xmit_skb(session, skb, session->hdr_len);
+ local_bh_enable();
sock_put(sk_tun);
sock_put(sk);