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

From: Lai Jiangshan
Date: Wed Sep 09 2015 - 21:04:36 EST


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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