Re: WARNING in usb_submit_urb (3)

[Andrey Konovalov]

On Mon, Oct 15, 2018 at 7:12 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> Ah, I see the problem.  In fact it is the same issue, but the commit
> mentioned above contains an error (is_in gets tested too soon).  The
> fix is below; can you check it?

You can ask syzbot to do this:

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
master
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 244417d0dfd1..ffccd40ea67d 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -1474,8 +1474,6 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb
 	u = 0;
 	switch (uurb->type) {
 	case USBDEVFS_URB_TYPE_CONTROL:
-		if (is_in)
-			allow_short = true;
 		if (!usb_endpoint_xfer_control(&ep->desc))
 			return -EINVAL;
 		/* min 8 byte setup packet */
@@ -1505,6 +1503,8 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb
 			is_in = 0;
 			uurb->endpoint &= ~USB_DIR_IN;
 		}
+		if (is_in)
+			allow_short = true;
 		snoop(&ps->dev->dev, "control urb: bRequestType=%02x "
 			"bRequest=%02x wValue=%04x "
 			"wIndex=%04x wLength=%04x\n",