{"id":812242,"url":"http://patchwork.ozlabs.org/api/patches/812242/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-pci/patch/20170911074542.16777-2-nstange@suse.de/","project":{"id":28,"url":"http://patchwork.ozlabs.org/api/projects/28/?format=json","name":"Linux PCI development","link_name":"linux-pci","list_id":"linux-pci.vger.kernel.org","list_email":"linux-pci@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20170911074542.16777-2-nstange@suse.de>","list_archive_url":null,"date":"2017-09-11T07:45:40","name":"[1/3] PCI: fix race condition with driver_override","commit_ref":null,"pull_url":null,"state":"accepted","archived":false,"hash":"7e193e58aea77b1d49023b7d2deb92059ad2f301","submitter":{"id":72345,"url":"http://patchwork.ozlabs.org/api/people/72345/?format=json","name":"Nicolai Stange","email":"nstange@suse.de"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linux-pci/patch/20170911074542.16777-2-nstange@suse.de/mbox/","series":[{"id":2449,"url":"http://patchwork.ozlabs.org/api/series/2449/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-pci/list/?series=2449","date":"2017-09-11T07:45:39","name":"make PCI's and platform's driver_override_store()/show() converge","version":1,"mbox":"http://patchwork.ozlabs.org/series/2449/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/812242/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/812242/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@bilbo.ozlabs.org","Authentication-Results":"ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=vger.kernel.org\n\t(client-ip=209.132.180.67; helo=vger.kernel.org;\n\tenvelope-from=linux-pci-owner@vger.kernel.org;\n\treceiver=)","Received":["from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 3xrKkH0rmsz9s81\n\tfor ;\n\tMon, 11 Sep 2017 17:46:31 +1000 (AEST)","(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1751090AbdIKHpu (ORCPT );\n\tMon, 11 Sep 2017 03:45:50 -0400","from mx2.suse.de ([195.135.220.15]:47683 \"EHLO mx1.suse.de\"\n\trhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP\n\tid S1751031AbdIKHpt (ORCPT );\n\tMon, 11 Sep 2017 03:45:49 -0400","from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254])\n\tby mx1.suse.de (Postfix) with ESMTP id D0507ABBF;\n\tMon, 11 Sep 2017 07:45:47 +0000 (UTC)"],"X-Virus-Scanned":"by amavisd-new at test-mx.suse.de","From":"Nicolai Stange ","To":"Bjorn Helgaas ,\n\tGreg Kroah-Hartman ","Cc":"Adrian Salido , Sasha Levin ,\n\tlinux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,\n\tNicolai Stange ","Subject":"[PATCH 1/3] PCI: fix race condition with driver_override","Date":"Mon, 11 Sep 2017 09:45:40 +0200","Message-Id":"<20170911074542.16777-2-nstange@suse.de>","X-Mailer":"git-send-email 2.13.5","In-Reply-To":"<20170911074542.16777-1-nstange@suse.de>","References":"<20170911074542.16777-1-nstange@suse.de>","Sender":"linux-pci-owner@vger.kernel.org","Precedence":"bulk","List-ID":"","X-Mailing-List":"linux-pci@vger.kernel.org"},"content":"The driver_override implementation is susceptible to a race condition when\ndifferent threads are reading vs. storing a different driver override.\nAdd locking to avoid the race condition.\n\nThis is in close analogy to commit 6265539776a0 (\"driver core: platform:\nfix race condition with driver_override\") from Adrian Salido.\n\nFixes: 782a985d7af2 (\"PCI: Introduce new device binding path using pci_dev.driver_override\")\nCc: stable@vger.kernel.org\t# v3.16+\nSigned-off-by: Nicolai Stange \n---\n drivers/pci/pci-sysfs.c | 11 +++++++++--\n 1 file changed, 9 insertions(+), 2 deletions(-)","diff":"diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c\nindex 1eecfa301f7f..8e075ea2743e 100644\n--- a/drivers/pci/pci-sysfs.c\n+++ b/drivers/pci/pci-sysfs.c\n@@ -686,7 +686,7 @@ static ssize_t driver_override_store(struct device *dev,\n \t\t\t\t const char *buf, size_t count)\n {\n \tstruct pci_dev *pdev = to_pci_dev(dev);\n-\tchar *driver_override, *old = pdev->driver_override, *cp;\n+\tchar *driver_override, *old, *cp;\n \n \t/* We need to keep extra room for a newline */\n \tif (count >= (PAGE_SIZE - 1))\n@@ -700,12 +700,15 @@ static ssize_t driver_override_store(struct device *dev,\n \tif (cp)\n \t\t*cp = '\\0';\n \n+\tdevice_lock(dev);\n+\told = pdev->driver_override;\n \tif (strlen(driver_override)) {\n \t\tpdev->driver_override = driver_override;\n \t} else {\n \t\tkfree(driver_override);\n \t\tpdev->driver_override = NULL;\n \t}\n+\tdevice_unlock(dev);\n \n \tkfree(old);\n \n@@ -716,8 +719,12 @@ static ssize_t driver_override_show(struct device *dev,\n \t\t\t\t struct device_attribute *attr, char *buf)\n {\n \tstruct pci_dev *pdev = to_pci_dev(dev);\n+\tssize_t len;\n \n-\treturn snprintf(buf, PAGE_SIZE, \"%s\\n\", pdev->driver_override);\n+\tdevice_lock(dev);\n+\tlen = snprintf(buf, PAGE_SIZE, \"%s\\n\", pdev->driver_override);\n+\tdevice_unlock(dev);\n+\treturn len;\n }\n static DEVICE_ATTR_RW(driver_override);\n \n","prefixes":["1/3"]}