On Sun, 21 Aug 2016, Jiri Slaby wrote: > Cc: proper lists. > > ep->desc.bInterval seems to be 0 here. > > On 08/21/2016, 12:42 PM, Vittorio Zecca wrote: > > I am not sure this is the right place so please bear with me... > > From Vittorio Zecca > > > > After compiling kernel 4.7.2 with ubsan I got the following messages > > at boot time: > > > > (devio.c:1713 is "as->urb->interval = 1 << min(15, ep->desc.bInterval - 1);") > > > > [ +0.354486] ================================================================================ > > [ +0.000008] UBSAN: Undefined behaviour in > > /home/vitti/1tb/vitti/rpmbuild/SOURCES/linux-4.7.2/drivers/usb/core/devio.c:1713:25 > > [ +0.000004] shift exponent -1 is negative As far as I can see, this isn't possible. The usb_parse_endpoint() routine in drivers/usb/core/config.c is supposed to guarantee that ep->desc.bInterval is never 0. More information from Vittorio would be helpful. For example, what shows up in /sys/kernel/debug/usb/devices (after mounting a debugfs filesystem on /sys/kernel/debug)? 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
