On Wed, Jan 08, 2014 at 10:48:06AM -0500, Alan Stern wrote: > On Tue, 7 Jan 2014, Greg KH wrote: > > > On Tue, Jan 07, 2014 at 05:44:26PM -0800, David Cohen wrote: > > > From: jianqian <jianqiang.tang@xxxxxxxxx> > > > > > > There is a possible kernel panic faced on xhci_suspend(). > > > Due to kernel modified the hub autosupend_delay to 0s, after usb1 root > > > hub finishes initialization, it will trigger runtime_suspend and then > > > it will trigger xhci runtime suspend. But at that time, if > > > xhci->shared_hcd is still doing initialization, it is possible to face > > > null pointer kernel panic in xhci_suspend() function. > > > > > > This patch checks if xhci->shared_hcd is null to avoid panic. > > > > That sounds like this is a race that should be fixed properly, not just > > papered over, right? > > That was my reaction too. The best way to solve the problem is to > prevent the USB-2 root hub from suspending until after the USB-3 root > hub has been registered. That makes sense. Thanks for the feedback. I'll check for a new approach. Br, David Cohen > > Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
