On Tue, Oct 6, 2020 at 3:23 AM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > On Mon, Oct 05, 2020 at 05:38:22PM -0600, Shuah Khan wrote: > > On 10/5/20 9:25 AM, Alan Stern wrote: > > > On Mon, Oct 05, 2020 at 05:21:30PM +0200, Andrey Konovalov wrote: > > > No, no -- it won't work right if it's called in process context. Not > > > only do the spinlock calls leave the interrupt flag unchanged, also the > > > driver callback routines may expect to be invoked with interrupts > > > disabled. (We have tried to fix this, but I'm not at all certain that > > > all the cases have been updated.) > > > > > > > In the case of vhci case, usb_hcd_giveback_urb() is called from vhci's > > urb_enqueue, when it determines it doesn't need to xmit the urb and can give > > it back. This path runs in task context. > > > > Do you have any recommendation on how this case can be handled? > > Just call local_irq_disable() before usb_hcd_giveback_urb(), and > local_irq_enable() afterward. OK, so overall it's possible to call usb_hcd_giveback_urb() in task context, but only with irqs disabled. This means we do need a fix for kcov as well, thank you!
