[3.8.y.z extended stable] Patch "l2tp: must disable bh before calling l2tp_xmit_skb()" has been added to staging queue
Kamal Mostafa
kamal at canonical.com
Fri Nov 1 21:43:40 UTC 2013
This is a note to let you know that I have just added a patch titled
l2tp: must disable bh before calling l2tp_xmit_skb()
to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree
which can be found at:
http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue
This patch is scheduled to be released in version 3.8.13.13.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
------
>From a7a8e3f795261b42cda190e13cfffcc872248747 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet at google.com>
Date: Thu, 10 Oct 2013 06:30:09 -0700
Subject: l2tp: must disable bh before calling l2tp_xmit_skb()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
[ 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 at alphalink.fr>
Tested-by: François Cachereul <f.cachereul at alphalink.fr>
Signed-off-by: Eric Dumazet <edumazet at google.com>
Cc: James Chapman <jchapman at katalix.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
net/l2tp/l2tp_ppp.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index c3c1152..6920a6f 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -352,7 +352,9 @@ 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);
@@ -421,7 +423,9 @@ 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);
--
1.8.1.2
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