On Fri, Nov 13, 2020 at 04:45:52PM +0000, John Boero wrote: > Sorry I wanted to include a pastebin or link but was trying to follow maillist > guidelines and not include links or exceed wrap guidelines. Full contents: > https://paste.centos.org/view/3746bc40 > > Yes I understand the return dodges the config dereference. > > Original line usb.c:281 is the original error: > > 280| for (i = 0; i < config->desc.bNumInterfaces; i++) > 281| if (config->interface[i]->altsetting[0] > 282| .desc.bInterfaceNumber == ifnum) > 283| return config->interface[i]; Okay. Without having looked at the code, I would guess that uvcvideo's uvc_ioctl_streamon() handler -- or some routine beneath it -- either doesn't lock the USB interface while starting I/O, or doesn't check (while holding the lock) to see whether the driver has been unbound. This sort of error (config->interface[i] == NULL) is what you expect to see if a driver tries to carry out I/O to a device that has been unplugged and that it has been unbound from. Alan Stern
