From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4113FA373D for ; Tue, 1 Nov 2022 09:41:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230470AbiKAJlY (ORCPT ); Tue, 1 Nov 2022 05:41:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230347AbiKAJkT (ORCPT ); Tue, 1 Nov 2022 05:40:19 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4774919288 for ; Tue, 1 Nov 2022 02:40:06 -0700 (PDT) Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1opnka-0007Kh-Ma; Tue, 01 Nov 2022 10:40:04 +0100 Received: from sha by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1opnka-0003Bi-D9; Tue, 01 Nov 2022 10:40:04 +0100 Date: Tue, 1 Nov 2022 10:40:04 +0100 From: Sascha Hauer To: Bjorn Helgaas Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Bjorn Helgaas , stable@vger.kernel.org Subject: Re: [PATCH] PCI/sysfs: Fix double free in error path Message-ID: <20221101094004.GD9130@pengutronix.de> References: <20221007065618.2169880-1-s.hauer@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221007065618.2169880-1-s.hauer@pengutronix.de> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-Accept-Language: de,en X-Accept-Content-Type: text/plain User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-pci@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Hi Bjorn, On Fri, Oct 07, 2022 at 08:56:18AM +0200, Sascha Hauer wrote: > When pci_create_attr() fails then pci_remove_resource_files() is called > which will iterate over the res_attr[_wc] arrays and frees every non > NULL entry. To avoid a double free here we have to set the failed entry > to NULL in pci_create_attr() when freeing it. > > Fixes: b562ec8f74e4 ("PCI: Don't leak memory if sysfs_create_bin_file() fails") > Signed-off-by: Sascha Hauer > Cc: > --- > drivers/pci/pci-sysfs.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) Any input to this one? There's this long unfixed race condition described here: https://patchwork.kernel.org/project/linux-pci/patch/20200716110423.xtfyb3n6tn5ixedh@pali/#23547255 And this patch at least prevents my system from crashing when this race condition occurs. Sascha > > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > index fc804e08e3cb5..a07381d46ddae 100644 > --- a/drivers/pci/pci-sysfs.c > +++ b/drivers/pci/pci-sysfs.c > @@ -1196,8 +1196,13 @@ static int pci_create_attr(struct pci_dev *pdev, int num, int write_combine) > res_attr->size = pci_resource_len(pdev, num); > res_attr->private = (void *)(unsigned long)num; > retval = sysfs_create_bin_file(&pdev->dev.kobj, res_attr); > - if (retval) > + if (retval) { > + if (write_combine) > + pdev->res_attr_wc[num] = NULL; > + else > + pdev->res_attr[num] = NULL; > kfree(res_attr); > + } > > return retval; > } > -- > 2.30.2 > > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |