Re: [PATCH] USB: don't read past config->interface[] if usb_control_msg() fails in usb_reset_configuration()

[Roel Kluin <roel.kluin@gmail.com>]

While looping over the interfaces, if usb_hcd_alloc_bandwidth() fails it calls
hcd->driver->reset_bandwidth(), so there was no need to reinstate the interface
again.

If no break occurred, the index equals config->desc.bNumInterfaces. A
subsequent usb_control_msg() failure resulted in a read from
config->interface[config->desc.bNumInterfaces] at label reset_old_alts.

In either case the last interface should be skipped.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
---
>> Could you please confirm whether this patch is the better or the
>> other (in this same thread)?
> 
> Can someone tell me which one is the correct one to apply, but resending
> it to me?

This is the one as Sarah kindly explained to me.

Thanks, Roel

diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 9bc95fe..1a48aac 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1471,7 +1471,7 @@ int usb_reset_configuration(struct usb_device *dev)
 	/* If not, reinstate the old alternate settings */
 	if (retval < 0) {
 reset_old_alts:
-		for (; i >= 0; i--) {
+		for (i--; i >= 0; i--) {
 			struct usb_interface *intf = config->interface[i];
 			struct usb_host_interface *alt;