Re: WARNING in usbhid_raw_request/usb_submit_urb (3)

[Alan Stern]

On Fri, 24 Apr 2020, syzbot wrote:

> Hello,
> 
> syzbot has tested the proposed patch and the reproducer did not trigger crash:

Let's try a slightly different fix.  This feels a little better; it 
reflects the fact that ep0 always exists, even when a device is 
unconfigured.  Also, it's a smaller change.

Alan Stern

#syz test: https://github.com/google/kasan.git 0fa84af8

Index: usb-devel/drivers/usb/core/message.c
===================================================================
--- usb-devel.orig/drivers/usb/core/message.c
+++ usb-devel/drivers/usb/core/message.c
@@ -1143,11 +1143,11 @@ void usb_disable_endpoint(struct usb_dev
 
 	if (usb_endpoint_out(epaddr)) {
 		ep = dev->ep_out[epnum];
-		if (reset_hardware)
+		if (reset_hardware && epnum != 0)
 			dev->ep_out[epnum] = NULL;
 	} else {
 		ep = dev->ep_in[epnum];
-		if (reset_hardware)
+		if (reset_hardware && epnum != 0)
 			dev->ep_in[epnum] = NULL;
 	}
 	if (ep) {