From patchwork Thu Apr 27 14:29:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Stein X-Patchwork-Id: 13225528 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 08DACC77B7F for ; Thu, 27 Apr 2023 14:29:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244073AbjD0O3R (ORCPT ); Thu, 27 Apr 2023 10:29:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48492 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244069AbjD0O3Q (ORCPT ); Thu, 27 Apr 2023 10:29:16 -0400 Received: from mx1.tq-group.com (mx1.tq-group.com [93.104.207.81]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D30030D6; Thu, 27 Apr 2023 07:29:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tq-group.com; i=@tq-group.com; q=dns/txt; s=key1; t=1682605754; x=1714141754; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=tCtpg2kzjPTTO6+C2f0a+KHi0QEOneW24SbJ2emNudM=; b=KuRJGzx8lV/sjwNP8LiRfyjcPYIr/uzas9q7X5CR1JLofBbzBeht2++J dWTwnz05ekqzDhTnbBuSZjciM9HdogMDwhebauSSGYwr7CoYj/+xs+EwU vAmunHg151Xw19B8ekWqdWISH8fRus9yC0BBHNAZ6gWgWlawHOMh9+wou Zvx4kohor+ahPXXrshk4uhHqizqsvq/3LctRlS//CKqW3Yys22SQ54v0g X4hYcXrjtO8V/0cfEIkILvUQCe7DjWoS0zY/qDqRhGPJxLbNaAf86Q2Yq x8DRawIcIO4bIe0LdjRWCD5beb8JK2kUktzWXM3fqccy6/nXfCmJZTntN w==; X-IronPort-AV: E=Sophos;i="5.99,230,1677538800"; d="scan'208";a="30607880" Received: from unknown (HELO tq-pgp-pr1.tq-net.de) ([192.168.6.15]) by mx1-pgp.tq-group.com with ESMTP; 27 Apr 2023 16:29:08 +0200 Received: from mx1.tq-group.com ([192.168.6.7]) by tq-pgp-pr1.tq-net.de (PGP Universal service); Thu, 27 Apr 2023 16:29:08 +0200 X-PGP-Universal: processed; by tq-pgp-pr1.tq-net.de on Thu, 27 Apr 2023 16:29:08 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tq-group.com; i=@tq-group.com; q=dns/txt; s=key1; t=1682605748; x=1714141748; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=tCtpg2kzjPTTO6+C2f0a+KHi0QEOneW24SbJ2emNudM=; b=L/YQ/vITar0NtqrbWXl/dzAKUrkYB78hr85SoNiuvkk2LgBeuBaxjq3O pHNBG/UPBA9e8J04M99Bs7W5MlpYEsSRbG8ULCnbGJzbrIGikXukmOuxn PP9mwMOAK42eLIvERYXunEQSUmUkyC+2zfc/WvR/34Yj1Ij6HfYNZ4WcV xTrRtb7ry/xPoOb1FeNX/eSKgI0yqMSUqUgphI9qUkhHzzSIhwDIXokM+ HdH+JEHvMZ8LxjAlN/OanFNsvnEEpVUpfXEAucSY+32nZXF3BOX9kB6zW XyfrVpykrcgsgVXO45fycQS405a5/4PsOxne+Hem5lgcBnZjQ/h9+fGfO Q==; X-IronPort-AV: E=Sophos;i="5.99,230,1677538800"; d="scan'208";a="30607879" Received: from vtuxmail01.tq-net.de ([10.115.0.20]) by mx1.tq-group.com with ESMTP; 27 Apr 2023 16:29:08 +0200 Received: from steina-w.tq-net.de (unknown [10.123.53.21]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by vtuxmail01.tq-net.de (Postfix) with ESMTPSA id 8F0A1280056; Thu, 27 Apr 2023 16:29:08 +0200 (CEST) From: Alexander Stein To: Bjorn Helgaas Cc: Alexander Stein , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Korneliusz Osmenda , Oliver Neukum Subject: [PATCH 3/3] PCI/sysfs: Fix sysfs init race condition Date: Thu, 27 Apr 2023 16:29:01 +0200 Message-Id: <20230427142901.3570536-4-alexander.stein@ew.tq-group.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230427142901.3570536-1-alexander.stein@ew.tq-group.com> References: <20230427142901.3570536-1-alexander.stein@ew.tq-group.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org sysfs attribute files for PCIe devices (pci_create_sysfs_dev_files) can be created by two paths: 1. pci_sysfs_init() 2. pci_bus_add_device() (drivers/pci/bus.c) There is a race during startup where an asynchronous PCIe host probe races against the pci_sysfs_init() late_initcall. In this case the PCIe devices are already added to the bus, for_each_pci_dev() will see them, but pci_bus_add_device() has not yet finished, so both code paths try to add the sysfs attributes. Fix this by waiting on a workqueue until sysfs has been initialized. pci_sysfs_init() needs the internal function without the check that sysfs_initialized has been set to 1. __pci_create_sysfs_dev_files still needs to remove resource files, which might have been created during pci_sysfs_init initcall. Signed-off-by: Alexander Stein --- drivers/pci/pci-sysfs.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 7d4733773633..3067d55f981c 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -29,9 +29,11 @@ #include #include #include +#include #include "pci.h" static int sysfs_initialized; /* = 0 */ +static DECLARE_WAIT_QUEUE_HEAD(sysfs_wq); /* show configuration fields */ #define pci_config_attr(field, format_string) \ @@ -997,8 +999,7 @@ static void __pci_create_legacy_files(struct pci_bus *b) */ void pci_create_legacy_files(struct pci_bus *b) { - if (!sysfs_initialized) - return; + wait_event(sysfs_wq, sysfs_initialized); __pci_create_legacy_files(b); } @@ -1501,13 +1502,18 @@ static const struct attribute_group pci_dev_resource_resize_group = { int __must_check __pci_create_sysfs_dev_files(struct pci_dev *pdev) { + /* + * sysfs attributes might already be created by pci_sysfs_init(), + * delete them here just in case + */ + pci_remove_resource_files(pdev); return pci_create_resource_files(pdev); } int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev) { - if (!sysfs_initialized) - return -EACCES; + /* Wait until sysfs has been initialized */ + wait_event(sysfs_wq, sysfs_initialized); return __pci_create_sysfs_dev_files(pdev); } @@ -1520,8 +1526,8 @@ int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev) */ void pci_remove_sysfs_dev_files(struct pci_dev *pdev) { - if (!sysfs_initialized) - return; + /* Wait until sysfs has been initialized */ + wait_event(sysfs_wq, sysfs_initialized); pci_remove_resource_files(pdev); } @@ -1532,9 +1538,8 @@ static int __init pci_sysfs_init(void) struct pci_bus *pbus = NULL; int retval; - sysfs_initialized = 1; for_each_pci_dev(pdev) { - retval = pci_create_sysfs_dev_files(pdev); + retval = __pci_create_sysfs_dev_files(pdev); if (retval) { pci_dev_put(pdev); return retval; @@ -1542,7 +1547,9 @@ static int __init pci_sysfs_init(void) } while ((pbus = pci_find_next_bus(pbus))) - pci_create_legacy_files(pbus); + __pci_create_legacy_files(pbus); + sysfs_initialized = 1; + wake_up_all(&sysfs_wq); return 0; }