Re: Is usb_hcd_giveback_urb() allowed in task context?

[Greg Kroah-Hartman]

On Mon, Oct 05, 2020 at 05:08:11PM +0200, Andrey Konovalov wrote:
> Dear USB and USB/IP maintainers,
> 
> While fuzzing the USB/IP stack with syzkaller we've stumbled upon an issue.
> 
> Currently kcov (the subsystem that is used for coverage collection)
> USB-related callbacks assume that usb_hcd_giveback_urb() can only be
> called from interrupt context, as indicated by the comment before the
> function definition. In the USB/IP code, however, it's called from the
> task context (see the stack trace below).
> 
> Is this something that is allowed and we need to fix kcov? Or is this
> a bug in USB/IP?

It's a bug in kcov, and is not true as you have found out :)

thanks,

greg k-h