Linux driver of vt6656 from staging area causes system to freeze.

[Greg Kroah-Hartman]

On Thu, Feb 03, 2022 at 01:41:11AM +0100, Philipp Hortmann wrote:
> I managed to get a device vt6656 (USB WiFi adapter). The device works OK
> when the computer is started and driver loaded. When the WLAN is disabled
> the system freezes often.
> 
> I am using ubuntu 20.04 with kernel 5.17.0-rc1 x86_64
> branch: staging-testing
> 
> After some tries I found out that it is a function in vnt_stop() main_usb.c
> with the following line that is causing this.
> usb_kill_urb(priv→interrupt_urb);
> But this memory is after this line still in use.

What "memory" do you mean?

> Digging deeper I found that the usb_submit_urb() function (in usbpipe.c
> vnt_start_interrupt_urb_complete) is called after the usb_kill_urb() is
> executed.
> 
> So I tied the execution of the usb_submit_urb() to a flag called
> DEVICE_FLAGS_DISCONNECTED. After that no crashes were observed.
> 
> So here my questions:
> - Is this the right place to fix?

Does it work for you?  If so, let's try it.

> - Do I need to log a bug report before a patch?

Not at all.  Please read the documention for how to submit a kernel
patch and we can take it from there.  The patch looks sane, now just
submit it correctly and we can review it and maybe apply it from there.

thanks,

greg k-h