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

[Alan Stern]

On Tue, 9 Feb 2010, Roel Kluin wrote:

> After the loop `for (i = 0; i < config->desc.bNumInterfaces; i++)' if no
> break occurred, i equals config->desc.bNumInterfaces. so if
> usb_control_msg() failed then after goto reset_old_alts we read from
> config->interface[config->desc.bNumInterfaces].

You correctly identified a problem, but your fix is wrong -- or at 
least, it is much too complicated.  The proper fix goes like this:

 	/* 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;
 

Alan Stern

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