Re: DVB suspend/resume regression on 3.19

[Takashi Iwai <tiwai@suse.de>]

At Mon, 09 Feb 2015 11:59:07 +0100,
Takashi Iwai wrote:
> 
> Hi,
> 
> we've got a bug report about the suspend/resume regression of DVB
> device with 3.19.  The symptom is VLC doesn't work after S3 or S4
> resume.  strace shows that /dev/dvb/adaptor0/dvr returns -ENODEV.
> 
> The reporter confirmed that 3.18 works fine, so the regression must be
> in 3.19.
> 
> There is a relevant kernel warning while suspending:
> 
>  WARNING: CPU: 1 PID: 3603 at ../kernel/module.c:1001 module_put+0xc7/0xd0()
>  Workqueue: events_unbound async_run_entry_fn
>   0000000000000000 ffffffff81a45779 ffffffff81664f12 0000000000000000
>   ffffffff81062381 0000000000000000 ffffffffa051eea0 ffff8800ca369278
>   ffffffffa051a068 ffff8800c0a18090 ffffffff810dfb47 0000000000000000
>  Call Trace:
>   [<ffffffff810055ac>] dump_trace+0x8c/0x340
>   [<ffffffff81005903>] show_stack_log_lvl+0xa3/0x190
>   [<ffffffff81007061>] show_stack+0x21/0x50
>   [<ffffffff81664f12>] dump_stack+0x47/0x67
>   [<ffffffff81062381>] warn_slowpath_common+0x81/0xb0
>   [<ffffffff810dfb47>] module_put+0xc7/0xd0
>   [<ffffffffa04d98d1>] dvb_usb_adapter_frontend_exit+0x41/0x60 [dvb_usb]
>   [<ffffffffa04d8451>] dvb_usb_exit+0x31/0xa0 [dvb_usb]
>   [<ffffffffa04d84fb>] dvb_usb_device_exit+0x3b/0x50 [dvb_usb]
>   [<ffffffff814cefad>] usb_unbind_interface+0x1ed/0x2c0
>   [<ffffffff8145ceae>] __device_release_driver+0x7e/0x100
>   [<ffffffff8145cf52>] device_release_driver+0x22/0x30
>   [<ffffffff814cf13d>] usb_forced_unbind_intf+0x2d/0x60
>   [<ffffffff814cf3c3>] usb_suspend+0x73/0x130
>   [<ffffffff814bd453>] usb_dev_freeze+0x13/0x20
>   [<ffffffff81468fca>] dpm_run_callback+0x4a/0x150
>   [<ffffffff81469c81>] __device_suspend+0x121/0x350
>   [<ffffffff81469ece>] async_suspend+0x1e/0xa0
>   [<ffffffff81081e63>] async_run_entry_fn+0x43/0x150
>   [<ffffffff81079e72>] process_one_work+0x142/0x3f0
>   [<ffffffff8107a234>] worker_thread+0x114/0x460
>   [<ffffffff8107f3b1>] kthread+0xc1/0xe0
>   [<ffffffff8166b77c>] ret_from_fork+0x7c/0xb0
> 
> So something went wrong in module refcount, which likely leads to
> disabling the device and returning -ENODEV in the end.
> 
> Does this ring a bell to you guys?
> 
> The hardware details and logs are found in the URL below:
>   https://bugzilla.novell.com/show_bug.cgi?id=916577

I wonder whether no one hits the same problem...?


Takashi