On a Intel E660/EG20T system I can observe the following lockdep splats:
[ 10.154920] =================================
[ 10.156026] [ INFO: inconsistent lock state ]
[ 10.156026] 3.16.0-rc5+ #13 Not tainted
[ 10.156026] ---------------------------------
[ 10.156026] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
[ 10.156026] swapper/1/0 [HC0[0]:SC1[5]:HE1:SE0] takes:
[ 10.156026] (_xmit_ETHER){?.-...}, at: [<80948b6a>] sch_direct_xmit+0x7a/0x250
[ 10.156026] {IN-HARDIRQ-W} state was registered at:
[ 10.156026] [<804811f0>] __lock_acquire+0x800/0x17a0
[ 10.156026] [<804828ba>] lock_acquire+0x6a/0xf0
[ 10.156026] [<809ed477>] _raw_spin_lock+0x27/0x40
[ 10.156026] [<8088d508>] gether_disconnect+0x68/0x280
[ 10.156026] [<8088e777>] eem_set_alt+0x37/0xc0
[ 10.156026] [<808847ce>] composite_setup+0x30e/0x1240
[ 10.156026] [<8088b8ae>] pch_udc_isr+0xa6e/0xf50
[ 10.156026] [<8048abe8>] handle_irq_event_percpu+0x38/0x1e0
[ 10.156026] [<8048adc1>] handle_irq_event+0x31/0x50
[ 10.156026] [<8048d94b>] handle_fasteoi_irq+0x6b/0x140
[ 10.156026] [<804040a5>] handle_irq+0x65/0x80
[ 10.156026] [<80403cfc>] do_IRQ+0x3c/0xc0
[ 10.156026] [<809ee6ae>] common_interrupt+0x2e/0x34
[ 10.156026] [<804668c5>] finish_task_switch+0x65/0xd0
[ 10.156026] [<809e89df>] __schedule+0x20f/0x7d0
[ 10.156026] [<809e94aa>] schedule_preempt_disabled+0x2a/0x70
[ 10.156026] [<8047bf03>] cpu_startup_entry+0x143/0x410
[ 10.156026] [<809e2e61>] rest_init+0xa1/0xb0
[ 10.156026] [<80ce2a3b>] start_kernel+0x336/0x33b
[ 10.156026] [<80ce22ab>] i386_start_kernel+0x79/0x7d
[ 10.156026] irq event stamp: 52070
[ 10.156026] hardirqs last enabled at (52070): [<809375de>] neigh_resolve_output+0xee/0x2a0
[ 10.156026] hardirqs last disabled at (52069): [<809375a8>] neigh_resolve_output+0xb8/0x2a0
[ 10.156026] softirqs last enabled at (52020): [<8044401f>] _local_bh_enable+0x1f/0x50
[ 10.156026] softirqs last disabled at (52021): [<80404036>] do_softirq_own_stack+0x26/0x30
[ 10.156026]
[ 10.156026] other info that might help us debug this:
[ 10.156026] Possible unsafe locking scenario:
[ 10.156026]
[ 10.156026] CPU0
[ 10.156026] ----
[ 10.156026] lock(_xmit_ETHER);
[ 10.156026] <Interrupt>
[ 10.156026] lock(_xmit_ETHER);
[ 10.156026]
[ 10.156026] *** DEADLOCK ***
[ 10.156026]
[ 10.156026] 4 locks held by swapper/1/0:
[ 10.156026] #0: (((&idev->mc_ifc_timer))){+.-...}, at: [<8044b100>] call_timer_fn+0x0/0x190
[ 10.156026] #1: (rcu_read_lock){......}, at: [<a0577c40>] mld_sendpack+0x0/0x590 [ipv6]
[ 10.156026] #2: (rcu_read_lock_bh){......}, at: [<a055680c>] ip6_finish_output2+0x4c/0x7f0 [ipv6]
[ 10.156026] #3: (rcu_read_lock_bh){......}, at: [<8092e510>] __dev_queue_xmit+0x0/0x5f0
[ 10.156026]
[ 10.156026] stack backtrace:
[ 10.156026] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.16.0-rc5+ #13
[ 10.156026] 811dbb10 00000000 9e919d10 809e6785 9e8b8000 9e919d3c 809e561e 80b95511
[ 10.156026] 80b9545a 80b9543d 80b95450 80b95441 80b957e4 9e8b84e0 00000002 8047f7b0
[ 10.156026] 9e919d5c 8048043b 00000002 00000000 9e8b8000 00000001 00000004 9e8b8000
[ 10.156026] Call Trace:
[ 10.156026] [<809e6785>] dump_stack+0x48/0x69
[ 10.156026] [<809e561e>] print_usage_bug+0x18f/0x19c
[ 10.156026] [<8047f7b0>] ? print_shortest_lock_dependencies+0x170/0x170
[ 10.156026] [<8048043b>] mark_lock+0x53b/0x5f0
[ 10.156026] [<804810cf>] __lock_acquire+0x6df/0x17a0
[ 10.156026] [<804828ba>] lock_acquire+0x6a/0xf0
[ 10.156026] [<80948b6a>] ? sch_direct_xmit+0x7a/0x250
[ 10.156026] [<809ed477>] _raw_spin_lock+0x27/0x40
[ 10.156026] [<80948b6a>] ? sch_direct_xmit+0x7a/0x250
[ 10.156026] [<80948b6a>] sch_direct_xmit+0x7a/0x250
[ 10.156026] [<8092e6bf>] __dev_queue_xmit+0x1af/0x5f0
[ 10.156026] [<80947fc0>] ? ether_setup+0x80/0x80
[ 10.156026] [<8092eb0f>] dev_queue_xmit+0xf/0x20
[ 10.156026] [<8093764c>] neigh_resolve_output+0x15c/0x2a0
[ 10.156026] [<a0556927>] ip6_finish_output2+0x167/0x7f0 [ipv6]
[ 10.156026] [<a0559b05>] ip6_finish_output+0x85/0x1c0 [ipv6]
[ 10.156026] [<a0559cb7>] ip6_output+0x77/0x240 [ipv6]
[ 10.156026] [<a0578163>] mld_sendpack+0x523/0x590 [ipv6]
[ 10.156026] [<80480501>] ? mark_held_locks+0x11/0x90
[ 10.156026] [<a057947d>] mld_ifc_timer_expire+0x15d/0x280 [ipv6]
[ 10.156026] [<8044b168>] call_timer_fn+0x68/0x190
[ 10.156026] [<a0579320>] ? igmp6_group_added+0x150/0x150 [ipv6]
[ 10.156026] [<8044b3fa>] run_timer_softirq+0x16a/0x240
[ 10.156026] [<a0579320>] ? igmp6_group_added+0x150/0x150 [ipv6]
[ 10.156026] [<80444984>] __do_softirq+0xd4/0x2f0
[ 10.156026] [<804448b0>] ? tasklet_action+0x100/0x100
[ 10.156026] [<80404036>] do_softirq_own_stack+0x26/0x30
[ 10.156026] <IRQ> [<80444d05>] irq_exit+0x65/0x70
[ 10.156026] [<8042d758>] smp_apic_timer_interrupt+0x38/0x50
[ 10.156026] [<809ee91f>] apic_timer_interrupt+0x2f/0x34
[ 10.156026] [<8048007b>] ? mark_lock+0x17b/0x5f0
[ 10.156026] [<8040a912>] ? default_idle+0x22/0xf0
[ 10.156026] [<8040b13e>] arch_cpu_idle+0xe/0x10
[ 10.156026] [<8047bfc6>] cpu_startup_entry+0x206/0x410
[ 10.156026] [<8042bfbd>] start_secondary+0x19d/0x1e0
Next try results in a different one:
[ 23.899317] g_ether gadget: high-speed config #1: CDC Ethernet (EEM)
[ 23.900918] IPv6: ADDRCONF(NETDEV_CHANGE): usb0: link becomes ready
[ 23.901573]
[ 23.903097] =================================
[ 23.904613] [ INFO: inconsistent lock state ]
[ 23.904613] 3.16.0-rc5+ #13 Not tainted
[ 23.904613] ---------------------------------
[ 23.904613] inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
[ 23.904613] kworker/0:1/29 [HC1[1]:SC0[2]:HE0:SE0] takes:
[ 23.904613] (&(&dev->tx_global_lock)->rlock){?.-...}, at: [<8088d4d4>] gether_disconnect+0x34/0x280
[ 23.904613] {HARDIRQ-ON-W} state was registered at:
[ 23.904613] [<804810cf>] __lock_acquire+0x6df/0x17a0
[ 23.904613] [<804828ba>] lock_acquire+0x6a/0xf0
[ 23.904613] [<809ed477>] _raw_spin_lock+0x27/0x40
[ 23.904613] [<809486ce>] dev_watchdog+0x1e/0x210
[ 23.904613] [<8044b168>] call_timer_fn+0x68/0x190
[ 23.904613] [<8044b3fa>] run_timer_softirq+0x16a/0x240
[ 23.904613] [<80444984>] __do_softirq+0xd4/0x2f0
[ 23.904613] [<80404036>] do_softirq_own_stack+0x26/0x30
[ 23.904613] [<80444d05>] irq_exit+0x65/0x70
[ 23.904613] [<8042d758>] smp_apic_timer_interrupt+0x38/0x50
[ 23.904613] [<809ee91f>] apic_timer_interrupt+0x2f/0x34
[ 23.904613] [<8040b13e>] arch_cpu_idle+0xe/0x10
[ 23.904613] [<8047bfc6>] cpu_startup_entry+0x206/0x410
[ 23.904613] [<8042bfbd>] start_secondary+0x19d/0x1e0
[ 23.904613] irq event stamp: 5255
[ 23.904613] hardirqs last enabled at (5254): [<809ed6e5>] _raw_spin_unlock_irqrestore+0x45/0x60
[ 23.904613] hardirqs last disabled at (5255): [<809ee6a7>] common_interrupt+0x27/0x34
[ 23.904613] softirqs last enabled at (5248): [<a05636f5>] ipv6_mc_up+0x35/0x40 [ipv6]
[ 23.904613] softirqs last disabled at (5250): [<a054e48e>] ip6_route_add+0x2ce/0x820 [ipv6]
[ 23.904613]
[ 23.904613] other info that might help us debug this:
[ 23.904613] Possible unsafe locking scenario:
[ 23.904613]
[ 23.904613] CPU0
[ 23.904613] ----
[ 23.904613] lock(&(&dev->tx_global_lock)->rlock);
[ 23.904613] <Interrupt>
[ 23.904613] lock(&(&dev->tx_global_lock)->rlock);
[ 23.904613]
[ 23.904613] *** DEADLOCK ***
[ 23.904613]
[ 23.904613] 5 locks held by kworker/0:1/29:
[ 23.904613] #0: ("events"){.+.+..}, at: [<804585a0>] process_one_work+0x100/0x4e0
[ 23.904613] #1: ((linkwatch_work).work){+.+...}, at: [<804585a0>] process_one_work+0x100/0x4e0
[ 23.904613] #2: (rtnl_mutex){+.+.+.}, at: [<809395d4>] rtnl_lock+0x14/0x20
[ 23.904613] #3: (&tb->tb6_lock){++....}, at: [<a054e48e>] ip6_route_add+0x2ce/0x820 [ipv6]
[ 23.904613] #4: (rcu_read_lock){......}, at: [<8091b2b0>] sock_def_readable+0x0/0xa0
[ 23.904613]
[ 23.904613] stack backtrace:
[ 23.904613] CPU: 0 PID: 29 Comm: kworker/0:1 Not tainted 3.16.0-rc5+ #13
[ 23.904613] Workqueue: events linkwatch_event
[ 23.904613] 811f3220 00000000 9e80bde8 809e6785 9e923340 9e80be14 809e561e 80b95511
[ 23.904613] 80b9545a 80b9543d 80b95450 80b95441 80b957fe 9e923838 00000000 8047f8b0
[ 23.904613] 9e80be34 8048043b 00000000 00000002 9e923340 00000001 0000000c 9e923340
[ 23.904613] Call Trace:
[ 23.904613] [<809e6785>] dump_stack+0x48/0x69
[ 23.904613] [<809e561e>] print_usage_bug+0x18f/0x19c
[ 23.904613] [<8047f8b0>] ? check_usage_backwards+0x100/0x100
[ 23.904613] [<8048043b>] mark_lock+0x53b/0x5f0
[ 23.904613] [<804811f0>] __lock_acquire+0x800/0x17a0
[ 23.904613] [<804828ba>] lock_acquire+0x6a/0xf0
[ 23.904613] [<8088d4d4>] ? gether_disconnect+0x34/0x280
[ 23.904613] [<809ed477>] _raw_spin_lock+0x27/0x40
[ 23.904613] [<8088d4d4>] ? gether_disconnect+0x34/0x280
[ 23.904613] [<8088d4d4>] gether_disconnect+0x34/0x280
[ 23.904613] [<8088e777>] eem_set_alt+0x37/0xc0
[ 23.904613] [<8088e740>] ? eem_disable+0x20/0x20
[ 23.904613] [<808847ce>] composite_setup+0x30e/0x1240
[ 23.904613] [<8088ae5e>] ? pch_udc_isr+0x1e/0xf50
[ 23.904613] [<8088b8ae>] pch_udc_isr+0xa6e/0xf50
[ 23.904613] [<8048abe8>] handle_irq_event_percpu+0x38/0x1e0
[ 23.904613] [<8048adc1>] handle_irq_event+0x31/0x50
[ 23.904613] [<8048d2d0>] ? handle_simple_irq+0x80/0x80
[ 23.904613] [<8048d32d>] handle_edge_irq+0x5d/0x110
[ 23.904613] [<804040a5>] handle_irq+0x65/0x80
[ 23.904613] <IRQ> [<80403cfc>] do_IRQ+0x3c/0xc0
[ 23.904613] [<809ee6ae>] common_interrupt+0x2e/0x34
[ 23.904613] [<8048007b>] ? mark_lock+0x17b/0x5f0
[ 23.904613] [<809ed6e7>] ? _raw_spin_unlock_irqrestore+0x47/0x60
[ 23.904613] [<8047ba01>] __wake_up_sync_key+0x41/0x50
[ 23.904613] [<8091b307>] sock_def_readable+0x57/0xa0
[ 23.904613] [<8094ab4e>] __netlink_sendskb+0x2e/0x40
[ 23.904613] [<8094b529>] netlink_broadcast_filtered+0x149/0x2f0
[ 23.904613] [<8094d3b4>] nlmsg_notify+0xb4/0xd0
[ 23.904613] [<80939972>] rtnl_notify+0x32/0x50
[ 23.904613] [<a0550218>] inet6_rt_notify+0xa8/0x110 [ipv6]
[ 23.904613] [<a0551e1b>] fib6_add+0x34b/0x7c0 [ipv6]
[ 23.904613] [<a054e4a4>] ip6_route_add+0x2e4/0x820 [ipv6]
[ 23.904613] [<a0543ff8>] addrconf_add_mroute.isra.38+0x58/0x60 [ipv6]
[ 23.904613] [<a05465b3>] addrconf_add_dev+0x53/0x90 [ipv6]
[ 23.904613] [<a054a3ee>] addrconf_notify+0x4ce/0x6a0 [ipv6]
[ 23.904613] [<809c36e0>] ? packet_notifier+0xb0/0x1e0
[ 23.904613] [<80462a39>] notifier_call_chain+0x49/0x70
[ 23.904613] [<80462b11>] raw_notifier_call_chain+0x11/0x20
[ 23.904613] [<80927fda>] call_netdevice_notifiers_info+0x2a/0x60
[ 23.904613] [<80929cfd>] netdev_state_change+0x2d/0x50
[ 23.904613] [<8093e3d3>] linkwatch_do_dev+0x33/0x50
[ 23.904613] [<8093e6a9>] __linkwatch_run_queue+0x109/0x130
[ 23.904613] [<8093e6f0>] linkwatch_event+0x20/0x30
[ 23.904613] [<804585fb>] process_one_work+0x15b/0x4e0
[ 23.904613] [<80458db1>] worker_thread+0x41/0x4c0
[ 23.904613] [<8048073b>] ? trace_hardirqs_on+0xb/0x10
[ 23.904613] [<80458d70>] ? create_and_start_worker+0x50/0x50
[ 23.904613] [<8045e3d8>] kthread+0xa8/0xc0
[ 23.904613] [<809edf81>] ret_from_kernel_thread+0x21/0x30
[ 23.904613] [<8045e330>] ? kthread_create_on_node+0x150/0x150
Aside of that something in that driver is really flakey and timing
sensitive, but before digging into that I'd like to figure out how to
fix the splats above.
Thanks,
tglx
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