4 if (!dev->isoc_ctl.cmd) { 205 c = (header >> 24) & 0xff; 206 Clearly, it was the trial to access *buf, at line 202 that caused the Panic. As ioctl is serialized, While S_STD is handled,QBUF/DQBUF won't be called. So, the driver will run out of the buffers, and *buf will become NULL. As, on tm6000, the same URB can contain more than one video buffer, it is likely to hit a condition where no new buffer is available whily copying the streams. The fix is to leave the URB copy loop, if there's no more buffers are available. The same bug could also be produced by an application that is not fast enough to request new video buffers. The same bug were reported by Bee Hock Goh . Thanks-to: Bee Hock Goh for reporting the bug Signed-off-by: Mauro Carvalho Chehab fQ€µ‘&x