Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753860Ab0FMWTx (ORCPT ); Sun, 13 Jun 2010 18:19:53 -0400 Received: from fg-out-1718.google.com ([72.14.220.157]:31007 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751902Ab0FMWTw (ORCPT ); Sun, 13 Jun 2010 18:19:52 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:content-transfer-encoding :in-reply-to:user-agent; b=k8fuKy+3Wk9C80s3e9uOrCZeCG/TeOPSnWiJifk0pHxhHtDemdl885NaERdvwJ1a98 OPLYeM4EQXIs2xbBSPgHT5I0+/nV2qNAYfH1TqtK5FR48wyjJZfEQlxfou9L1PPhUh4z 5S0OrlpySnlm3oQdWfak0ZX2ugGTAHdOi80cU= Date: Mon, 14 Jun 2010 00:18:03 +0200 From: Marcin Slusarz To: x86@kernel.org Cc: LKML , Pekka Paalanen , Stuart Bennett , Marcin =?utf-8?Q?Ko=C5=9Bcielnicki?= , Shinpei KATO , nouveau@lists.freedesktop.org, Ingo Molnar Subject: Re: [PATCHv2] kmmio/mmiotrace: fix double free of kmmio_fault_pages Message-ID: <20100613221803.GB3829@joi.lan> References: <20100613215654.GA3829@joi.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20100613215654.GA3829@joi.lan> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1351 Lines: 30 On Sun, Jun 13, 2010 at 11:56:54PM +0200, Marcin Slusarz wrote: > After every iounmap mmiotrace has to free kmmio_fault_pages, but it > can't do it directly, so it defers freeing by RCU. > > It usually works, but when mmiotraced code calls ioremap-iounmap > multiple times without sleeping between (so RCU won't kick in and > start freeing) it can be given the same virtual address, so at > every iounmap mmiotrace will schedule the same pages for release. > Obviously it will explode on second free. > > Fix it by marking kmmio_fault_pages which are scheduled for release > and not adding them second time. > > Signed-off-by: Marcin Slusarz > Acked-by: Pekka Paalanen > Cc: Stuart Bennett > Tested-by: Marcin Kościelnicki > Tested-by: Shinpei KATO > --- It would be good to apply it to -stable too. Sometimes people has to test some earlier kernels because of unfixable constraints (you know, these uncooperative vendors not releasing their binary drivers for latest kernels) Marcin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/