Hi Jukka, I think there's a lock checking option in the kernel hacking configuration menu. Might be worth trying this to get more info. I had a quick look through the code and there maybe a potential locking problem in l2cap_le_credits it calls l2cap_get_chan_by_dcid which locks the channel lock (chan->lock) which is one of the locks in the deadlock below. If credits > max_credits in l2cap_le_credits it returns 0 but no unlock. Now l2cap_send_disconn_req may do this, I tried searching through but it called a state_change op so I gave up. http://lxr.free-electrons.com/source/net/bluetooth/l2cap_core.c#L5539 You could try sticking a l2cap_chan_unlock(chan); in to see if the problem goes away. Alex have you tried this patch in a virtual emulator or on real HW for 802.15.4? we would know if it's a bluetooth or general problem. - Martin On 13/10/14 12:49, Jukka Rissanen wrote: > Hi Martin, > > with this v6 I started to see similar issues locking issues as in some > earlier patch version. I will try v5 and v4 just to make sure what is > going on here. > > > [ 308.736047] ================================= > [ 308.736047] [ INFO: inconsistent lock state ] > [ 308.736047] 3.17.0-rc1-bt6lowpan #1 Not tainted > [ 308.736047] --------------------------------- > [ 308.736047] inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage. > [ 308.736047] kworker/u3:2/404 [HC0[0]:SC0[0]:HE1:SE1] takes: > [ 308.736047] (&(&list->lock)->rlock#6){+.?...}, at: [<f82a8d4c>] > hci_send_acl+0xac/0x290 [bluetooth] > [ 308.736047] {IN-SOFTIRQ-W} state was registered at: > [ 308.736047] [<c10915a3>] __lock_acquire+0x6d3/0x1d20 > [ 308.736047] [<c109325d>] lock_acquire+0x9d/0x140 > [ 308.736047] [<c1889c25>] _raw_spin_lock+0x45/0x80 > [ 308.736047] [<f82a8d4c>] hci_send_acl+0xac/0x290 [bluetooth] > [ 308.736047] [<f82c9bf0>] l2cap_do_send+0x60/0x100 [bluetooth] > [ 308.736047] [<f82cd7c0>] l2cap_chan_send+0x7f0/0x10e0 [bluetooth] > [ 308.736047] [<f850d91e>] send_pkt+0x4e/0xa0 [bluetooth_6lowpan] > [ 308.736047] [<f850dd20>] bt_xmit+0x3b0/0x770 [bluetooth_6lowpan] > [ 308.736047] [<c17742f4>] dev_hard_start_xmit+0x344/0x670 > [ 308.736047] [<c17749ad>] __dev_queue_xmit+0x38d/0x680 > [ 308.736047] [<c1774caf>] dev_queue_xmit+0xf/0x20 > [ 308.736047] [<c177b8b0>] neigh_connected_output+0x130/0x1a0 > [ 308.736047] [<c1812a63>] ip6_finish_output2+0x173/0x8c0 > [ 308.736047] [<c18182db>] ip6_finish_output+0x7b/0x1b0 > [ 308.736047] [<c18184a7>] ip6_output+0x97/0x2a0 > [ 308.736047] [<c183a46b>] mld_sendpack+0x5eb/0x650 > [ 308.736047] [<c183acc1>] mld_ifc_timer_expire+0x191/0x2f0 > [ 308.736047] [<c10ac385>] call_timer_fn+0x85/0x1c0 > [ 308.736047] [<c10acb72>] run_timer_softirq+0x192/0x280 > [ 308.736047] [<c104fd84>] __do_softirq+0xd4/0x300 > [ 308.736047] [<c10049fc>] do_softirq_own_stack+0x2c/0x40 > [ 308.736047] [<c1050136>] irq_exit+0x86/0xb0 > [ 308.736047] [<c188bd98>] smp_apic_timer_interrupt+0x38/0x50 > [ 308.736047] [<c188b6ce>] apic_timer_interrupt+0x32/0x38 > [ 308.736047] [<c115e6b2>] kmem_cache_alloc+0x1c2/0x290 > [ 308.736047] [<c116a9ae>] create_object+0x2e/0x280 > [ 308.736047] [<c187f10c>] kmemleak_alloc+0x3c/0xb0 > [ 308.736047] [<c115e693>] kmem_cache_alloc+0x1a3/0x290 > [ 308.736047] [<c1178835>] getname_flags+0x25/0x110 > [ 308.736047] [<c117d21e>] user_path_at_empty+0x1e/0x80 > [ 308.736047] [<c1173317>] SyS_readlinkat+0x57/0x100 > [ 308.736047] [<c11733ec>] SyS_readlink+0x2c/0x30 > [ 308.736047] [<c188aeb6>] syscall_after_call+0x0/0x4 > [ 308.736047] irq event stamp: 37665 > [ 308.736047] hardirqs last enabled at (37665): [<c188a065>] > _raw_spin_unlock_irqrestore+0x55/0x70 > [ 308.736047] hardirqs last disabled at (37664): [<c1889e03>] > _raw_spin_lock_irqsave+0x23/0x90 > [ 308.736047] softirqs last enabled at (37378): [<c104ff5c>] > __do_softirq+0x2ac/0x300 > [ 308.736047] softirqs last disabled at (37359): [<c10049fc>] > do_softirq_own_stack+0x2c/0x40 > [ 308.736047] > [ 308.736047] other info that might help us debug this: > [ 308.736047] Possible unsafe locking scenario: > [ 308.736047] > [ 308.736047] CPU0 > [ 308.736047] ---- > [ 308.736047] lock(&(&list->lock)->rlock#6); > [ 308.736047] <Interrupt> > [ 308.736047] lock(&(&list->lock)->rlock#6); > [ 308.736047] > [ 308.736047] *** DEADLOCK *** > [ 308.736047] > [ 308.736047] 3 locks held by kworker/u3:2/404: > [ 308.736047] #0: ("%s"hdev->name#2){.+.+.+}, at: [<c10622c3>] > process_one_work+0x113/0x4a0 > [ 308.736047] #1: ((&hdev->rx_work)){+.+.+.}, at: [<c10622c3>] > process_one_work+0x113/0x4a0 > [ 308.736047] #2: (&chan->lock){+.+.+.}, at: [<f82c9179>] > l2cap_get_chan_by_dcid+0x89/0x90 [bluetooth] > [ 308.736047] > [ 308.736047] stack backtrace: > [ 308.736047] CPU: 0 PID: 404 Comm: kworker/u3:2 Not tainted > 3.17.0-rc1-bt6lowpan #1 > [ 308.736047] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS > VirtualBox 12/01/2006 > [ 308.736047] Workqueue: hci0 hci_rx_work [bluetooth] > [ 308.736047] efe3d780 00000000 efedbb90 c18821c1 c2345c10 efedbbb0 > c1880a94 c1ad9264 > [ 308.736047] c1ad9201 c1ad95f8 efe3dd94 00000006 c108e0c0 efedbbe0 > c108ea8c 00000006 > [ 308.736047] efe3d780 efedbffc e21128f4 00000047 00000004 efe3d780 > efe3dd98 00000003 > [ 308.736047] Call Trace: > [ 308.736047] [<c18821c1>] dump_stack+0x4b/0x75 > [ 308.736047] [<c1880a94>] print_usage_bug.part.36+0x209/0x213 > [ 308.736047] [<c108e0c0>] ? check_usage_forwards+0x110/0x110 > [ 308.736047] [<c108ea8c>] mark_lock+0x11c/0x6e0 > [ 308.736047] [<c10915e4>] __lock_acquire+0x714/0x1d20 > [ 308.736047] [<c1004b6f>] ? dump_trace+0xcf/0x1f0 > [ 308.736047] [<c100a5f8>] ? sched_clock+0x8/0x10 > [ 308.736047] [<c1075da9>] ? sched_clock_local+0x49/0x180 > [ 308.736047] [<c109325d>] lock_acquire+0x9d/0x140 > [ 308.736047] [<f82a8d4c>] ? hci_send_acl+0xac/0x290 [bluetooth] > [ 308.736047] [<c1889c25>] _raw_spin_lock+0x45/0x80 > [ 308.736047] [<f82a8d4c>] ? hci_send_acl+0xac/0x290 [bluetooth] > [ 308.736047] [<f82a8d4c>] hci_send_acl+0xac/0x290 [bluetooth] > [ 308.736047] [<c108f0b4>] ? mark_held_locks+0x64/0x90 > [ 308.736047] [<c188a065>] ? _raw_spin_unlock_irqrestore+0x55/0x70 > [ 308.736047] [<f82c9bf0>] l2cap_do_send+0x60/0x100 [bluetooth] > [ 308.736047] [<c108f32b>] ? trace_hardirqs_on+0xb/0x10 > [ 308.736047] [<c188a051>] ? _raw_spin_unlock_irqrestore+0x41/0x70 > [ 308.736047] [<c1763125>] ? skb_dequeue+0x45/0x60 > [ 308.736047] [<f82d4389>] l2cap_recv_frame+0x23d9/0x2db0 [bluetooth] > [ 308.736047] [<c1075da9>] ? sched_clock_local+0x49/0x180 > [ 308.736047] [<c100a5f8>] ? sched_clock+0x8/0x10 > [ 308.736047] [<c1075da9>] ? sched_clock_local+0x49/0x180 > [ 308.736047] [<c10761ef>] ? sched_clock_cpu+0x10f/0x160 > [ 308.736047] [<c107183b>] ? get_parent_ip+0xb/0x40 > [ 308.736047] [<c10718bb>] ? preempt_count_add+0x4b/0xa0 > [ 308.736047] [<c13d09e2>] ? debug_smp_processor_id+0x12/0x20 > [ 308.736047] [<c108cc04>] ? get_lock_stats+0x24/0x40 > [ 308.736047] [<c108f0b4>] ? mark_held_locks+0x64/0x90 > [ 308.736047] [<c188716d>] ? __mutex_unlock_slowpath+0xcd/0x1b0 > [ 308.736047] [<c13d09ff>] ? __this_cpu_preempt_check+0xf/0x20 > [ 308.736047] [<c108f1d4>] ? trace_hardirqs_on_caller+0xf4/0x240 > [ 308.736047] [<c108c9a6>] ? trace_hardirqs_off_caller+0xb6/0x160 > [ 308.736047] [<f82d62a9>] l2cap_recv_acldata+0x2f9/0x340 [bluetooth] > [ 308.736047] [<f82a1a13>] ? hci_rx_work+0x113/0x4a0 [bluetooth] > [ 308.736047] [<f82a1c69>] hci_rx_work+0x369/0x4a0 [bluetooth] > [ 308.736047] [<f82a1a13>] ? hci_rx_work+0x113/0x4a0 [bluetooth] > [ 308.736047] [<c106234a>] process_one_work+0x19a/0x4a0 > [ 308.736047] [<c10622c3>] ? process_one_work+0x113/0x4a0 > [ 308.736047] [<c10629e9>] worker_thread+0x39/0x440 > [ 308.736047] [<c10629b0>] ? init_pwq+0xc0/0xc0 > [ 308.736047] [<c1066dc8>] kthread+0xa8/0xc0 > [ 308.736047] [<c108f32b>] ? trace_hardirqs_on+0xb/0x10 > [ 308.736047] [<c188ad01>] ret_from_kernel_thread+0x21/0x30 > [ 308.736047] [<c1066d20>] ? kthread_create_on_node+0x160/0x160 > > > > Cheers, > Jukka > > -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
