Re: usb/media/hdpvr: trying to register non-static key in hdpvr_probe

[Arvind Yadav <arvind.yadav.cs@gmail.com>]

Hi Andrey,


On Friday 22 September 2017 05:16 PM, Andrey Konovalov wrote:
> On Fri, Sep 22, 2017 at 9:41 AM, Arvind Yadav <arvind.yadav.cs@gmail.com> wrote:
>> Hi,
>>
>> I have a doubt. Why we are calling flush_work in hdpvr_probe for every
>> failure.
>> We are flushing work which is not defined yet.
>>
>> Here, hdpvr_register_videodev() is responsible for setup and register a
>> video device.
>> Also defining and initializing a worker. we are calling
>> hdpvr_register_videodev() at last.
>> No need to flash any work here.
>>
>> Please correct me, if I am wrong.
> Hi Arvind,
>
> I believe you're right, no need to call flush_work() before
> dev->worker is initialized.
>
> Could you send a fix?
>
> I'm able to reproduce the issue, so I can test your patches if needed.
I have send a one patch to you. which will resolve this error. But my 
question is why
hdpvr_probe() is failing. We need to find out. Could please share more 
information and logs.

~arvind
> Thanks!
>
>>
>> On Thursday 21 September 2017 09:09 PM, Andrey Konovalov wrote:
>>> Hi!
>>>
>>> I've got the following report while fuzzing the kernel with syzkaller.
>>>
>>> On commit ebb2c2437d8008d46796902ff390653822af6cc4 (Sep 18).
>>>
>>> INFO: trying to register non-static key.
>>> the code is fine but needs lockdep annotation.
>>> turning off the locking correctness validator.
>>> CPU: 0 PID: 24 Comm: kworker/0:1 Not tainted
>>> 4.14.0-rc1-42251-gebb2c2437d80 #215
>>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
>>> 01/01/2011
>>> Workqueue: usb_hub_wq hub_event
>>> Call Trace:
>>>    __dump_stack lib/dump_stack.c:16
>>>    dump_stack+0x292/0x395 lib/dump_stack.c:52
>>>    register_lock_class+0x6c4/0x1a00 kernel/locking/lockdep.c:769
>>>    __lock_acquire+0x27e/0x4550 kernel/locking/lockdep.c:3385
>>>    lock_acquire+0x259/0x620 kernel/locking/lockdep.c:4002
>>>    flush_work+0xf0/0x8c0 kernel/workqueue.c:2886
>>>    hdpvr_probe+0x233/0x20d0 drivers/media/usb/hdpvr/hdpvr-core.c:400
>>>    usb_probe_interface+0x35d/0x8e0 drivers/usb/core/driver.c:361
>>>    really_probe drivers/base/dd.c:413
>>>    driver_probe_device+0x610/0xa00 drivers/base/dd.c:557
>>>    __device_attach_driver+0x230/0x290 drivers/base/dd.c:653
>>>    bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463
>>>    __device_attach+0x26e/0x3d0 drivers/base/dd.c:710
>>>    device_initial_probe+0x1f/0x30 drivers/base/dd.c:757
>>>    bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523
>>>    device_add+0xd0b/0x1660 drivers/base/core.c:1835
>>>    usb_set_configuration+0x104e/0x1870 drivers/usb/core/message.c:1932
>>>    generic_probe+0x73/0xe0 drivers/usb/core/generic.c:174
>>>    usb_probe_device+0xaf/0xe0 drivers/usb/core/driver.c:266
>>>    really_probe drivers/base/dd.c:413
>>>    driver_probe_device+0x610/0xa00 drivers/base/dd.c:557
>>>    __device_attach_driver+0x230/0x290 drivers/base/dd.c:653
>>>    bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463
>>>    __device_attach+0x26e/0x3d0 drivers/base/dd.c:710
>>>    device_initial_probe+0x1f/0x30 drivers/base/dd.c:757
>>>    bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523
>>>    device_add+0xd0b/0x1660 drivers/base/core.c:1835
>>>    usb_new_device+0x7b8/0x1020 drivers/usb/core/hub.c:2457
>>>    hub_port_connect drivers/usb/core/hub.c:4903
>>>    hub_port_connect_change drivers/usb/core/hub.c:5009
>>>    port_event drivers/usb/core/hub.c:5115
>>>    hub_event+0x194d/0x3740 drivers/usb/core/hub.c:5195
>>>    process_one_work+0xc7f/0x1db0 kernel/workqueue.c:2119
>>>    worker_thread+0x221/0x1850 kernel/workqueue.c:2253
>>>    kthread+0x3a1/0x470 kernel/kthread.c:231
>>>    ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431
>>> hdpvr: probe of 1-1:8.217 failed with error -12
>> ~arvind