Hello,
I've had the following lockdep report for the last couple of years of
kernels. I don't think I've had a lockup during that time related to
pppoe.
The pppoe entry in the MAINTAINERS file lists Michal Ostrowski <mostrows@xxxxxxxxxxxxx>
which unfortunately bounces.
Regards
Yanko
[ 123.603836] ======================================================
[ 123.603838] [ INFO: possible circular locking dependency detected ]
[ 123.603842] 3.8.0-0.rc7.git3.1.fc19.x86_64 #1 Not tainted
[ 123.603844] -------------------------------------------------------
[ 123.603846] liferea/2399 is trying to acquire lock:
[ 123.603848] (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-...}, at: [<ffffffff815c9478>] dev_queue_xmit+0x8b8/0x900
[ 123.603860]
but task is already holding lock:
[ 123.603862] (&(&pch->downl)->rlock){+.-...}, at: [<ffffffffa0637d6d>] ppp_push+0x12d/0x630 [ppp_generic]
[ 123.603872]
which lock already depends on the new lock.
[ 123.603875]
the existing dependency chain (in reverse order) is:
[ 123.603877]
-> #3 (&(&pch->downl)->rlock){+.-...}:
[ 123.603881] [<ffffffff810db302>] lock_acquire+0xa2/0x1f0
[ 123.603887] [<ffffffff81704d2b>] _raw_spin_lock_bh+0x4b/0x80
[ 123.603892] [<ffffffffa0637d6d>] ppp_push+0x12d/0x630 [ppp_generic]
[ 123.603896] [<ffffffffa063a9df>] ppp_xmit_process+0x43f/0x670 [ppp_generic]
[ 123.603900] [<ffffffffa063afb0>] ppp_write+0xf0/0x110 [ppp_generic]
[ 123.603904] [<ffffffff811d8f32>] vfs_write+0xa2/0x170
[ 123.603908] [<ffffffff811d90ec>] sys_write+0x4c/0xa0
[ 123.603910] [<ffffffff8170eb59>] system_call_fastpath+0x16/0x1b
[ 123.603916]
-> #2 (&(&ppp->wlock)->rlock){+.-...}:
[ 123.603920] [<ffffffff810db302>] lock_acquire+0xa2/0x1f0
[ 123.603923] [<ffffffff81704d2b>] _raw_spin_lock_bh+0x4b/0x80
[ 123.603926] [<ffffffffa063a5cc>] ppp_xmit_process+0x2c/0x670 [ppp_generic]
[ 123.603930] [<ffffffffa063ae3d>] ppp_start_xmit+0x13d/0x1c0 [ppp_generic]
[ 123.603933] [<ffffffff815c8209>] dev_hard_start_xmit+0x259/0x6c0
[ 123.603936] [<ffffffff815e9dfe>] sch_direct_xmit+0xee/0x290
[ 123.603940] [<ffffffff815c8db6>] dev_queue_xmit+0x1f6/0x900
[ 123.603943] [<ffffffff815cfda1>] neigh_direct_output+0x11/0x20
[ 123.603946] [<ffffffff8160a0c9>] ip_finish_output+0x2b9/0x7f0
[ 123.603950] [<ffffffff8160c2bc>] ip_output+0x5c/0x100
[ 123.603952] [<ffffffff8160b649>] ip_local_out+0x29/0x90
[ 123.603955] [<ffffffff8160cdf5>] ip_send_skb+0x15/0x50
[ 123.603958] [<ffffffff8160ce63>] ip_push_pending_frames+0x33/0x40
[ 123.603960] [<ffffffff8163f6b5>] icmp_push_reply+0xf5/0x130
[ 123.603964] [<ffffffff8164096d>] icmp_send+0x49d/0xc80
[ 123.603966] [<ffffffff8163c709>] __udp4_lib_rcv+0x469/0xa80
[ 123.603969] [<ffffffff8163cd3a>] udp_rcv+0x1a/0x20
[ 123.603971] [<ffffffff8160497e>] ip_local_deliver_finish+0x19e/0x4c0
[ 123.603974] [<ffffffff81605697>] ip_local_deliver+0x47/0x80
[ 123.603977] [<ffffffff81604e00>] ip_rcv_finish+0x160/0x760
[ 123.603979] [<ffffffff816058e9>] ip_rcv+0x219/0x340
[ 123.603982] [<ffffffff815c6712>] __netif_receive_skb+0xad2/0xdc0
[ 123.603985] [<ffffffff815c7b1e>] process_backlog+0xbe/0x1a0
[ 123.603988] [<ffffffff815c7112>] net_rx_action+0x172/0x380
[ 123.603990] [<ffffffff81072b6f>] __do_softirq+0xef/0x3d0
[ 123.603994] [<ffffffff8170fefc>] call_softirq+0x1c/0x30
[ 123.603998] [<ffffffff8101c495>] do_softirq+0x85/0xc0
[ 123.604002] [<ffffffff81073035>] irq_exit+0xd5/0xe0
[ 123.604005] [<ffffffff817107a6>] do_IRQ+0x56/0xc0
[ 123.604008] [<ffffffff81705c32>] ret_from_intr+0x0/0x1a
[ 123.604011] [<ffffffff81022add>] default_idle+0x5d/0x550
[ 123.604015] [<ffffffff810243fc>] cpu_idle+0x10c/0x170
[ 123.604018] [<ffffffff816f11dd>] start_secondary+0x263/0x265
[ 123.604022]
-> #1 (_xmit_PPP#2){+.-...}:
[ 123.604026] [<ffffffff810db302>] lock_acquire+0xa2/0x1f0
[ 123.604029] [<ffffffff81704ca6>] _raw_spin_lock+0x46/0x80
[ 123.604032] [<ffffffff815e9dc0>] sch_direct_xmit+0xb0/0x290
[ 123.604035] [<ffffffff815c8db6>] dev_queue_xmit+0x1f6/0x900
[ 123.604038] [<ffffffff815cfda1>] neigh_direct_output+0x11/0x20
[ 123.604040] [<ffffffff8160a0c9>] ip_finish_output+0x2b9/0x7f0
[ 123.604043] [<ffffffff8160c2bc>] ip_output+0x5c/0x100
[ 123.604046] [<ffffffff8160b649>] ip_local_out+0x29/0x90
[ 123.604048] [<ffffffff8160bad3>] ip_queue_xmit+0x1b3/0x670
[ 123.604051] [<ffffffff81625e62>] tcp_transmit_skb+0x3e2/0xa60
[ 123.604054] [<ffffffff81626676>] tcp_write_xmit+0x196/0xad0
[ 123.604057] [<ffffffff8162721e>] __tcp_push_pending_frames+0x2e/0xc0
[ 123.604060] [<ffffffff81616ebd>] tcp_sendmsg+0x11d/0xe00
[ 123.604063] [<ffffffff81646b17>] inet_sendmsg+0x117/0x230
[ 123.604066] [<ffffffff815a971a>] sock_sendmsg+0xaa/0xe0
[ 123.604071] [<ffffffff815ac079>] sys_sendto+0x129/0x1d0
[ 123.604073] [<ffffffff8170eb59>] system_call_fastpath+0x16/0x1b
[ 123.604077]
-> #0 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-...}:
[ 123.604080] [<ffffffff810da8b1>] __lock_acquire+0x17e1/0x1a80
[ 123.604083] [<ffffffff810db302>] lock_acquire+0xa2/0x1f0
[ 123.604086] [<ffffffff81704ca6>] _raw_spin_lock+0x46/0x80
[ 123.604089] [<ffffffff815c9478>] dev_queue_xmit+0x8b8/0x900
[ 123.604091] [<ffffffffa06562b2>] __pppoe_xmit+0x142/0x190 [pppoe]
[ 123.604095] [<ffffffffa0656311>] pppoe_xmit+0x11/0x20 [pppoe]
[ 123.604098] [<ffffffffa0637d88>] ppp_push+0x148/0x630 [ppp_generic]
[ 123.604101] [<ffffffffa063a9df>] ppp_xmit_process+0x43f/0x670 [ppp_generic]
[ 123.604105] [<ffffffffa063ae3d>] ppp_start_xmit+0x13d/0x1c0 [ppp_generic]
[ 123.604108] [<ffffffff815c8209>] dev_hard_start_xmit+0x259/0x6c0
[ 123.604111] [<ffffffff815e9dfe>] sch_direct_xmit+0xee/0x290
[ 123.604114] [<ffffffff815c8db6>] dev_queue_xmit+0x1f6/0x900
[ 123.604117] [<ffffffff815cfda1>] neigh_direct_output+0x11/0x20
[ 123.604120] [<ffffffff8160a0c9>] ip_finish_output+0x2b9/0x7f0
[ 123.604123] [<ffffffff8160c2bc>] ip_output+0x5c/0x100
[ 123.604125] [<ffffffff8160b649>] ip_local_out+0x29/0x90
[ 123.604128] [<ffffffff8160bad3>] ip_queue_xmit+0x1b3/0x670
[ 123.604131] [<ffffffff81625e62>] tcp_transmit_skb+0x3e2/0xa60
[ 123.604134] [<ffffffff81628b74>] tcp_send_ack+0xa4/0xf0
[ 123.604137] [<ffffffff81617c46>] tcp_cleanup_rbuf+0x76/0x120
[ 123.604140] [<ffffffff816189ca>] tcp_recvmsg+0x72a/0xd50
[ 123.604143] [<ffffffff81646fc9>] inet_recvmsg+0x129/0x220
[ 123.604146] [<ffffffff815a9859>] sock_recvmsg+0xb9/0xf0
[ 123.604149] [<ffffffff815ac227>] sys_recvfrom+0xe7/0x160
[ 123.604152] [<ffffffff8170eb59>] system_call_fastpath+0x16/0x1b
[ 123.604155]
other info that might help us debug this:
[ 123.604158] Chain exists of:
dev->qdisc_tx_busylock ?: &qdisc_tx_busylock --> &(&ppp->wlock)->rlock --> &(&pch->downl)->rlock
[ 123.604163] Possible unsafe locking scenario:
[ 123.604165] CPU0 CPU1
[ 123.604167] ---- ----
[ 123.604168] lock(&(&pch->downl)->rlock);
[ 123.604171] lock(&(&ppp->wlock)->rlock);
[ 123.604173] lock(&(&pch->downl)->rlock);
[ 123.604175] lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
[ 123.604178]
*** DEADLOCK ***
[ 123.604181] 8 locks held by liferea/2399:
[ 123.604182] #0: (sk_lock-AF_INET){+.+.+.}, at: [<ffffffff816182d2>] tcp_recvmsg+0x32/0xd50
[ 123.604188] #1: (rcu_read_lock){.+.+..}, at: [<ffffffff8160b925>] ip_queue_xmit+0x5/0x670
[ 123.604194] #2: (rcu_read_lock_bh){.+....}, at: [<ffffffff81609f48>] ip_finish_output+0x138/0x7f0
[ 123.604199] #3: (rcu_read_lock_bh){.+....}, at: [<ffffffff815c8bc5>] dev_queue_xmit+0x5/0x900
[ 123.604204] #4: (_xmit_PPP#2){+.-...}, at: [<ffffffff815e9dc0>] sch_direct_xmit+0xb0/0x290
[ 123.604210] #5: (&(&ppp->wlock)->rlock){+.-...}, at: [<ffffffffa063a5cc>] ppp_xmit_process+0x2c/0x670 [ppp_generic]
[ 123.604216] #6: (&(&pch->downl)->rlock){+.-...}, at: [<ffffffffa0637d6d>] ppp_push+0x12d/0x630 [ppp_generic]
[ 123.604222] #7: (rcu_read_lock_bh){.+....}, at: [<ffffffff815c8bc5>] dev_queue_xmit+0x5/0x900
[ 123.604227]
stack backtrace:
[ 123.604231] Pid: 2399, comm: liferea Not tainted 3.8.0-0.rc7.git3.1.fc19.x86_64 #1
[ 123.604233] Call Trace:
[ 123.604239] [<ffffffff816f9c6e>] print_circular_bug+0x201/0x210
[ 123.604243] [<ffffffff810da8b1>] __lock_acquire+0x17e1/0x1a80
[ 123.604246] [<ffffffff810d93b5>] ? __lock_acquire+0x2e5/0x1a80
[ 123.604250] [<ffffffff810db302>] lock_acquire+0xa2/0x1f0
[ 123.604253] [<ffffffff815c9478>] ? dev_queue_xmit+0x8b8/0x900
[ 123.604257] [<ffffffff81704ca6>] _raw_spin_lock+0x46/0x80
[ 123.604260] [<ffffffff815c9478>] ? dev_queue_xmit+0x8b8/0x900
[ 123.604263] [<ffffffff815c9478>] dev_queue_xmit+0x8b8/0x900
[ 123.604267] [<ffffffff815c8bc5>] ? dev_queue_xmit+0x5/0x900
[ 123.604270] [<ffffffffa06562b2>] __pppoe_xmit+0x142/0x190 [pppoe]
[ 123.604274] [<ffffffffa0656311>] pppoe_xmit+0x11/0x20 [pppoe]
[ 123.604278] [<ffffffffa0637d88>] ppp_push+0x148/0x630 [ppp_generic]
[ 123.604282] [<ffffffff810d8c9c>] ? trace_hardirqs_on_caller+0xac/0x190
[ 123.604285] [<ffffffff810d8d8d>] ? trace_hardirqs_on+0xd/0x10
[ 123.604289] [<ffffffffa063a9df>] ppp_xmit_process+0x43f/0x670 [ppp_generic]
[ 123.604292] [<ffffffff810d8d8d>] ? trace_hardirqs_on+0xd/0x10
[ 123.604296] [<ffffffffa063ae3d>] ppp_start_xmit+0x13d/0x1c0 [ppp_generic]
[ 123.604300] [<ffffffff815c8209>] dev_hard_start_xmit+0x259/0x6c0
[ 123.604303] [<ffffffff815e9dfe>] sch_direct_xmit+0xee/0x290
[ 123.604307] [<ffffffff815c8db6>] dev_queue_xmit+0x1f6/0x900
[ 123.604310] [<ffffffff815c8bc5>] ? dev_queue_xmit+0x5/0x900
[ 123.604313] [<ffffffff815cfda1>] neigh_direct_output+0x11/0x20
[ 123.604316] [<ffffffff8160a0c9>] ip_finish_output+0x2b9/0x7f0
[ 123.604319] [<ffffffff81609f48>] ? ip_finish_output+0x138/0x7f0
[ 123.604323] [<ffffffff8160c2bc>] ip_output+0x5c/0x100
[ 123.604326] [<ffffffff8160b649>] ip_local_out+0x29/0x90
[ 123.604329] [<ffffffff8160bad3>] ip_queue_xmit+0x1b3/0x670
[ 123.604332] [<ffffffff8160b925>] ? ip_queue_xmit+0x5/0x670
[ 123.604335] [<ffffffff81625e62>] tcp_transmit_skb+0x3e2/0xa60
[ 123.604339] [<ffffffff811b8a19>] ? ksize+0x19/0xc0
[ 123.604342] [<ffffffff81628b74>] tcp_send_ack+0xa4/0xf0
[ 123.604346] [<ffffffff81617c46>] tcp_cleanup_rbuf+0x76/0x120
[ 123.604350] [<ffffffff816189ca>] tcp_recvmsg+0x72a/0xd50
[ 123.604354] [<ffffffff810ad465>] ? sched_clock_cpu+0xb5/0x100
[ 123.604358] [<ffffffff81646fc9>] inet_recvmsg+0x129/0x220
[ 123.604361] [<ffffffff815a9859>] sock_recvmsg+0xb9/0xf0
[ 123.604365] [<ffffffff810d93b5>] ? __lock_acquire+0x2e5/0x1a80
[ 123.604368] [<ffffffff815ac227>] sys_recvfrom+0xe7/0x160
[ 123.604372] [<ffffffff8170eb85>] ? sysret_check+0x22/0x5d
[ 123.604376] [<ffffffff810d8ced>] ? trace_hardirqs_on_caller+0xfd/0x190
[ 123.604381] [<ffffffff8136094e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[ 123.604385] [<ffffffff8170eb59>] system_call_fastpath+0x16/0x1b
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