From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757465AbXIVTat (ORCPT ); Sat, 22 Sep 2007 15:30:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751275AbXIVTan (ORCPT ); Sat, 22 Sep 2007 15:30:43 -0400 Received: from www.osadl.org ([213.239.205.134]:48918 "EHLO mail.tglx.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751549AbXIVTam (ORCPT ); Sat, 22 Sep 2007 15:30:42 -0400 Subject: Re: [PATCH] usb-gadget-ether: Prevent oops caused by error interrupt race -V2 (comments update) From: Thomas Gleixner To: David Brownell Cc: stable@kernel.org, linux-kernel@vger.kernel.org, bene@linutronix.de, akpm@osdl.org In-Reply-To: <20070922191806.A2F59C2308@adsl-69-226-248-13.dsl.pltn13.pacbell.net> References: <1190299611.3481.34.camel@chaos> <200709211508.42968.david-b@pacbell.net> <1190482861.4035.59.camel@chaos> <20070922191806.A2F59C2308@adsl-69-226-248-13.dsl.pltn13.pacbell.net> Content-Type: text/plain Date: Sat, 22 Sep 2007 21:30:40 +0200 Message-Id: <1190489440.4035.103.camel@chaos> Mime-Version: 1.0 X-Mailer: Evolution 2.12.0 (2.12.0-3.fc8) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2007-09-22 at 12:18 -0700, David Brownell wrote: > I think you misread my comment. Those requests are **NOT** pending!! > So this update has a *MORE* incorrect description of the issue. > > That's just the freelist ... it's a fairly conventional model whereby > there's a pool of "free" request slots which can be issued. When the > pool empties, the TX queue shuts down until one of the requests which > is pending in the hardware completes, and makes a slot free. > > The problem you're addressing is that there's a small window where a > disconnect IRQ can shut down the TX queue (and empty that freelist) > after upper layers in the network stack started a transmission on > an active (pre-disconnect) TX queue. > > That problem is *NOT* related to any pending requests at all!! Sorry, I misunderstood your comment. Can you please add the correct comment yourself before we play some more rounds of ping pong ? tglx