Re: [Linux v4.2] workqueue: llvmlinux: acpid: BUG: sleeping function called from invalid context at kernel/workqueue.c:2680

[Lai Jiangshan]

Hi, TJ

I think we need to add might_sleep() on the top of __cancel_work_timer().
The might_sleep() on the start_flush_work() doesn't cover all the
paths of __cancel_work_timer().
And it can help to narrow the area of this bug.

Hi Sedat Dilek

[   24.705704] irq event stamp: 19968
[   24.705706] hardirqs last  enabled at (19967): [<ffffffff81917ff2>]
_raw_spin_unlock_irq+0x32/0x60
[   24.705713] hardirqs last disabled at (19968): [<ffffffff81120477>]
del_timer_sync+0x37/0x110

Is it means the irq-disabled-event is leak by del_timer_sync()? It is
impossible.

usbhid_close()
  mutex_lock(); // it has might_sleep() check. So the problem seems to be
                // hidden at one of the following statements
  del_timer_sync();
  cancel_work_sync();


On Wed, Sep 9, 2015 at 6:24 PM, Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote:
> [ TO WORKQUEUE maintainers ]
>
> Hi,
>
> I encountered a BUG with a llvmlinux compiled kernel here on
> Ubuntu/precise AMD64 touching the workqueue area.
>
> [   24.705463] BUG: sleeping function called from invalid context at
> kernel/workqueue.c:2680
> [   24.705576] in_atomic(): 0, irqs_disabled(): 1, pid: 1447, name: acpid
> [   24.705662] 3 locks held by acpid/1447:
> [   24.705664]  #0:  (&evdev->mutex){+.+...}, at: [<ffffffff8173b9ac>]
> evdev_release+0xbc/0xf0
> [   24.705678]  #1:  (&dev->mutex#2){+.+...}, at: [<ffffffff81733117>]
> input_close_device+0x27/0x70
> [   24.705691]  #2:  (hid_open_mut){+.+...}, at: [<ffffffffa0056378>]
> usbhid_close+0x28/0xb0 [usbhid]
> [   24.705704] irq event stamp: 19968
> [   24.705706] hardirqs last  enabled at (19967): [<ffffffff81917ff2>]
> _raw_spin_unlock_irq+0x32/0x60
> [   24.705713] hardirqs last disabled at (19968): [<ffffffff81120477>]
> del_timer_sync+0x37/0x110
> [   24.705720] softirqs last  enabled at (18890): [<ffffffff8189e7c9>]
> local_bh_enable+0x9/0x20
> [   24.705726] softirqs last disabled at (18888): [<ffffffff8189e7a9>]
> local_bh_disable+0x9/0x20
> [   24.705734] CPU: 2 PID: 1447 Comm: acpid Not tainted
> 4.2.0-2-llvmlinux-small #2
> [   24.705737] Hardware name: SAMSUNG ELECTRONICS CO., LTD.
> 530U3BI/530U4BI/530U4BH/530U3BI/530U4BI/530U4BH, BIOS 13XK 03/28/2013
> [   24.705741]  ffff8800d57ea948 0000000000000092 0000000000000000
> ffff8800bb3e3aa8
> [   24.705748]  ffffffff8149287d ffff8800bb3e3ad8 ffffffff810cbf7a
> ffffffff81c51a34
> [   24.705754]  ffff8800d3095000 0000000000000000 0000000000000a78
> ffff8800bb3e3b18
> [   24.705761] Call Trace:
> [   24.705767]  [<ffffffff8149287d>] dump_stack+0x7d/0xa0
> [   24.705774]  [<ffffffff810cbf7a>] ___might_sleep+0x28a/0x2a0
> [   24.705779]  [<ffffffff810cbc7f>] __might_sleep+0x4f/0xc0
> [   24.705784]  [<ffffffff810ae8ff>] start_flush_work+0x2f/0x290
> [   24.705789]  [<ffffffff810ae8ac>] flush_work+0x5c/0x80
> [   24.705792]  [<ffffffff810ae86a>] ? flush_work+0x1a/0x80
> [   24.705799]  [<ffffffff810eddcd>] ? trace_hardirqs_off+0xd/0x10
> [   24.705804]  [<ffffffff810ad938>] ? try_to_grab_pending+0x48/0x360
> [   24.705810]  [<ffffffff81917e13>] ? _raw_spin_lock_irqsave+0x73/0x80
> [   24.705814]  [<ffffffff810aecf9>] __cancel_work_timer+0x179/0x260
> [   24.705820]  [<ffffffff81917f92>] ? _raw_spin_unlock_irqrestore+0x52/0x80
> [   24.705825]  [<ffffffff8112042d>] ? try_to_del_timer_sync+0xad/0xc0
> [   24.705829]  [<ffffffff810aeb78>] cancel_work_sync+0x18/0x20
> [   24.705835]  [<ffffffffa00563c5>] usbhid_close+0x75/0xb0 [usbhid]
> [   24.705844]  [<ffffffffa0039431>] hidinput_close+0x31/0x40 [hid]
> [   24.705851]  [<ffffffffa0039400>] ? hidinput_open+0x40/0x40 [hid]
> [   24.705856]  [<ffffffff81733138>] input_close_device+0x48/0x70
> [   24.705861]  [<ffffffff8173b9c6>] evdev_release+0xd6/0xf0
> [   24.705867]  [<ffffffff8126ed37>] __fput+0x107/0x240
> [   24.705872]  [<ffffffff8126ebc6>] ____fput+0x16/0x20
> [   24.705877]  [<ffffffff810b8107>] task_work_run+0x87/0x130
> [   24.705883]  [<ffffffff810173ef>] do_notify_resume+0x9cf/0xa00
> [   24.705888]  [<ffffffff810edddd>] ? trace_hardirqs_on+0xd/0x10
> [   24.705895]  [<ffffffff811d1cc3>] ? context_tracking_user_enter+0x13/0x20
> [   24.705900]  [<ffffffff81029c31>] ? syscall_trace_leave+0x111/0x340
> [   24.705905]  [<ffffffff8126eb56>] ? fput+0x76/0xd0
> [   24.705909]  [<ffffffff8126b415>] ? filp_close+0x65/0x90
> [   24.705915]  [<ffffffff81003017>] ? trace_hardirqs_on_thunk+0x17/0x19
> [   24.705920]  [<ffffffff81918dae>] int_signal+0x12/0x17
>
> Attached are the full dmesg-log and my kernel-config.
>
> Which area in the kernel is the root cause? CC more people?
>
> Do you need more informations?
> How can I help?
>
> Regards,
> - Sedat -
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