On Mon, 2016-04-11 at 08:07 +0300, Felipe Balbi wrote: > Hi, > > chunfeng yun <chunfeng.yun@xxxxxxxxxxxx> writes: > > On Fri, 2016-04-08 at 07:07 -0700, Greg Kroah-Hartman wrote: > >> On Fri, Apr 08, 2016 at 05:08:03PM +0800, Chunfeng Yun wrote: > >> > NULL pointer dereferrence will happen when class driver > >> > wants to allocate zero length buffer and pool_max[0] > >> > can't be used, so skip reserved pool in this case. > >> > >> Why would a driver want to allocate a 0 length buffer? What driver does > >> this? > > It's misc/usbtest.c > > that'll do what you ask it to do with the userspace tool testusb. Are > you trying to pass a size of 0 ? > No, I just ran "testusb -t10" which called test_ctrl_queue(). In this function, sub-case 8 passed a parameter @len as 0 to simple_alloc_urb(), and then it tried to allocate a 0-length buffer. > >> Shouldn't we fix that issue instead? > > I don't know which way is better, but it seems simple to fix it up in > > buffer.c > > I think we should, really, avoid a 0-length allocation, but passing a > size of 0 to testusb isn't very good either ;-) How are you calling > testusb ? > As explained above. -- 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
