From stern@rowland.harvard.edu Tue May 15 14:40:46 2007
Date: Tue, 15 May 2007 17:40:37 -0400 (EDT)
From: Alan Stern <stern@rowland.harvard.edu>
To: Greg KH <greg@kroah.com>, Andrew Morton <akpm@linux-foundation.org>
Subject: USB: don't try to kzalloc 0 bytes
Message-ID: <Pine.LNX.4.44L0.0705151732060.5034-100000@iolanthe.rowland.org>

This patch (as907) prevents us from trying to allocate 0 bytes
when an interface has no endpoint descriptors.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/usb/core/config.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -185,10 +185,12 @@ static int usb_parse_interface(struct de
 		num_ep = USB_MAXENDPOINTS;
 	}
 
-	len = sizeof(struct usb_host_endpoint) * num_ep;
-	alt->endpoint = kzalloc(len, GFP_KERNEL);
-	if (!alt->endpoint)
-		return -ENOMEM;
+	if (num_ep > 0) {	/* Can't allocate 0 bytes */
+		len = sizeof(struct usb_host_endpoint) * num_ep;
+		alt->endpoint = kzalloc(len, GFP_KERNEL);
+		if (!alt->endpoint)
+			return -ENOMEM;
+	}
 
 	/* Parse all the endpoint descriptors */
 	n = 0;