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

[Andrey Konovalov]

On Fri, Sep 22, 2017 at 9:41 AM, Arvind Yadav <arvind.yadav.cs@xxxxxxxxx> 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.

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