From: Bjørn Mork <bjorn@mork.no>
Date: Mon, 16 Jan 2012 11:41:47 +0000 (+0100)
Subject: USB: cdc-wdm: updating desc->length must be protected by spin_lock
X-Git-Tag: v2.6.32.56~8
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=89b6c4ea1a545908809604812e23a7f83ba782e8;p=linux-pvops.git

USB: cdc-wdm: updating desc->length must be protected by spin_lock

commit c428b70c1e115c5649707a602742e34130d19428 upstream.

wdm_in_callback() will also touch this field, so we cannot change it without locking

Signed-off-by: Bjørn Mork <bjorn@mork.no>
Acked-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index 696ca75fdea8..d71514b87531 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -458,7 +458,9 @@ retry:
 	for (i = 0; i < desc->length - cntr; i++)
 		desc->ubuf[i] = desc->ubuf[i + cntr];
 
+	spin_lock_irq(&desc->iuspin);
 	desc->length -= cntr;
+	spin_unlock_irq(&desc->iuspin);
 	/* in case we had outstanding data */
 	if (!desc->length)
 		clear_bit(WDM_READ, &desc->flags);