khubd deadlock

[john]

reset on Bus 001 Device 003: ID 0557:2221 ATEN International Co., Ltd Winbond Hermon

create a deadlock, we have tested the 4.4 lts kernel backport and the issue doesn't happen

[ 539.927315] usb 1-1.3: reset full-speed USB device number 3 using ehci-pci
[ 544.999473] usb 1-1.3: device descriptor read/64, error -32
[ 545.175468] usb 1-1.3: device descriptor read/64, error -32
[ 545.351491] usb 1-1.3: reset full-speed USB device number 3 using ehci-pci
[ 545.423491] usb 1-1.3: device descriptor read/64, error -32
[ 545.599483] usb 1-1.3: device descriptor read/64, error -32
[ 545.775490] usb 1-1.3: reset full-speed USB device number 3 using ehci-pci
[ 546.183514] usb 1-1.3: device not accepting address 3, error -32
[ 546.255522] usb 1-1.3: reset full-speed USB device number 3 using ehci-pci
[ 546.663529] usb 1-1.3: device not accepting address 3, error -32
[ 546.664092] usb 1-1.3: USB disconnect, device number 3[ 740.878782] INFO: task khubd:34 blocked for more than 120 seconds.
[ 740.878858] Not tainted 3.16.0-77-generic #99~14.04.1-Ubuntu
[ 740.878918] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 740.878984] khubd D 0000000000000000 0 34 2 0x00000000
[ 740.878993] ffff880175f77c50 0000000000000246 ffff8801769ba8c0 00000000000130c0
[ 740.878998] ffff880175f77fd8 00000000000130c0 ffff8801768bc750 ffff8800032d48f0
[ 740.879002] ffff8800032d48f4 ffff8801769ba8c0 00000000ffffffff ffff8800032d48f8
[ 740.879006] Call Trace:
[ 740.879021] [<ffffffff81771e09>] schedule_preempt_disabled+0x29/0x70
[ 740.879027] [<ffffffff81773c15>] __mutex_lock_slowpath+0xd5/0x1d0
[ 740.879032] [<ffffffff81773d2f>] mutex_lock+0x1f/0x2f
[ 740.879039] [<ffffffff81567aa4>] usb_disconnect+0x54/0x2c0
[ 740.879044] [<ffffffff81571364>] ? usb_control_msg+0xd4/0x110
[ 740.879048] [<ffffffff81569762>] hub_port_connect+0x82/0x9e0
[ 740.879052] [<ffffffff8156a88b>] hub_events+0x7cb/0xcb0
[ 740.879059] [<ffffffff81775080>] ? _raw_spin_unlock_irqrestore+0x20/0x40
[ 740.879063] [<ffffffff8156ada5>] hub_thread+0x35/0x150
[ 740.879071] [<ffffffff810b6a40>] ? prepare_to_wait_event+0x100/0x100
[ 740.879075] [<ffffffff8156ad70>] ? hub_events+0xcb0/0xcb0
[ 740.879083] [<ffffffff81092a99>] kthread+0xc9/0xe0
[ 740.879089] [<ffffffff810929d0>] ? kthread_create_on_node+0x1c0/0x1c0
[ 740.879093] [<ffffffff81775858>] ret_from_fork+0x58/0x90
[ 740.879098] [<ffffffff810929d0>] ? kthread_create_on_node+0x1c0/0x1c0
[ 740.879102] INFO: task kworker/0:1:39 blocked for more than 120 seconds.
[ 740.879165] Not tainted 3.16.0-77-generic #99~14.04.1-Ubuntu
[ 740.879225] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 740.879289] kworker/0:1 D 0000000000000000 0 39 2 0x00000000
[ 740.879315] Workqueue: events hid_reset [usbhid]
[ 740.879317] ffff880175793850 0000000000000246 ffff8801769bc750 00000000000130c0
[ 740.879321] ffff880175793fd8 00000000000130c0 ffffffff81c1a480 ffff880175793998
[ 740.879325] ffff8801757939a0 7fffffffffffffff ffff8801769bc750 ffff8801769bc750
[ 740.879329] Call Trace:
[ 740.879334] [<ffffffff81771909>] schedule+0x29/0x70
[ 740.879339] [<ffffffff81770cd9>] schedule_timeout+0x269/0x2e0
[ 740.879345] [<ffffffff8109f657>] ? finish_task_switch+0x57/0x180
[ 740.879350] [<ffffffff81771472>] ? __schedule+0x362/0x7d0
[ 740.879355] [<ffffffff81772406>] wait_for_completion+0xa6/0x150
[ 740.879360] [<ffffffff810a2e80>] ? wake_up_state+0x20/0x20
[ 740.879365] [<ffffffff8108c2ed>] flush_work+0xed/0x1b0
[ 740.879369] [<ffffffff81088720>] ? destroy_worker+0x90/0x90
[ 740.879374] [<ffffffff8108c4b3>] __cancel_work_timer+0x93/0x1a0
[ 740.879382] [<ffffffff8107bb5b>] ? lock_timer_base.isra.34+0x2b/0x50
[ 740.879387] [<ffffffff81775080>] ? _raw_spin_unlock_irqrestore+0x20/0x40
[ 740.879392] [<ffffffff8108c5d0>] cancel_work_sync+0x10/0x20
[ 740.879400] [<ffffffffc03a04fa>] usbhid_close+0x6a/0x120 [usbhid]
[ 740.879410] [<ffffffffc0499f5a>] hidinput_close+0x1a/0x20 [hid]
[ 740.879417] [<ffffffff815b8e5a>] input_close_device+0x4a/0x70
[ 740.879423] [<ffffffff81482752>] kbd_disconnect+0x12/0x30
[ 740.879427] [<ffffffff815bb3f5>] __input_unregister_device+0xc5/0x1b0
[ 740.879431] [<ffffffff815bb58d>] input_unregister_device+0x4d/0x80
[ 740.879440] [<ffffffffc049a5d0>] hidinput_disconnect+0x90/0xc0 [hid]
[ 740.879447] [<ffffffffc0496ea0>] hid_disconnect+0x60/0x70 [hid]
[ 740.879455] [<ffffffffc0496f6d>] hid_device_remove+0xbd/0xd0 [hid]
[ 740.879463] [<ffffffff814bf6af>] __device_release_driver+0x7f/0xf0
[ 740.879466] [<ffffffff814bf743>] device_release_driver+0x23/0x30
[ 740.879470] [<ffffffff814bf048>] bus_remove_device+0x108/0x180

[john (jcbsth)]

This regression appears to have been introduced in 3.16.0-52.71~14.04.1

No problem with 3.16.0-51.69~14.04.1