Return-path: Received: from fmmailgate02.web.de ([217.72.192.227]:42855 "EHLO fmmailgate02.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752903AbYLEOrt (ORCPT ); Fri, 5 Dec 2008 09:47:49 -0500 From: Christian Lamparter To: linux-wireless@vger.kernel.org Subject: [PATCH] p54usb: fix usb_kill_urb hang with slub_debug=P Date: Fri, 5 Dec 2008 15:47:45 +0100 Cc: Johannes Berg , John W Linville , linux-usb@vger.kernel.org, gregkh@suse.de, linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Message-Id: <200812051547.45790.chunkeey@web.de> (sfid-20081205_154754_659087_A9B5593C) Sender: linux-wireless-owner@vger.kernel.org List-ID: This patch fixes a problem identified by Johannes Berg. It looks like this is a classic case of "use-after-freed". A module which should reproduce the problem on any other USB device can be found right here: http://kerneltrap.org/mailarchive/linux-usb/2008/12/4/4317064 Tested-by: Johannes Berg Signed-off-by: Christian Lamparter CC: stable@vger.kernel.org --- diff --git a/drivers/net/wireless/p54/p54usb.c b/drivers/net/wireless/p54/p54usb.c index 3444f52..0b9a922 100644 --- a/drivers/net/wireless/p54/p54usb.c +++ b/drivers/net/wireless/p54/p54usb.c @@ -209,7 +209,14 @@ static void p54u_free_urbs(struct ieee80211_hw *dev) if (!info->urb) continue; + /* + * usb_get_urb and usb_free_urb are part of a temporary + * workaround. Otherwise we get a pretty bad freeze, + * if SLUB's poisoning debug option is enabled. + */ + usb_get_urb(info->urb); usb_kill_urb(info->urb); + usb_free_urb(info->urb); kfree_skb(skb); } }