From patchwork Sat Feb 8 15:22:30 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 318431 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id C4F832C0078 for ; Sun, 9 Feb 2014 02:07:57 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751799AbaBHPH4 (ORCPT ); Sat, 8 Feb 2014 10:07:56 -0500 Received: from v094114.home.net.pl ([79.96.170.134]:61772 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751818AbaBHPHz (ORCPT ); Sat, 8 Feb 2014 10:07:55 -0500 Received: from afdw19.neoplus.adsl.tpnet.pl [95.49.100.19] (HELO vostro.rjw.lan) by serwer1319399.home.pl [79.96.170.134] with SMTP (IdeaSmtpServer v0.80) id 9b47c623ce58e63f; Sat, 8 Feb 2014 16:07:53 +0100 From: "Rafael J. Wysocki" To: ACPI Devel Maling List Cc: Linux PCI , Linux Kernel Mailing List Subject: [PATCH] ACPI / hotplug / PCI: Execute _EJ0 under the ACPI scan lock Date: Sat, 08 Feb 2014 16:22:30 +0100 Message-ID: <1629492.WLGZp2sePX@vostro.rjw.lan> User-Agent: KMail/4.11.4 (Linux/3.13.0+; KDE/4.11.4; x86_64; ; ) MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Rafael J. Wysocki Since acpi_device_hotplug() assumes that ACPI handles of device objects passed to it will not become invalid while acpi_scan_lock is being held, make acpiphp_disable_slot() acquire acpi_scan_lock, because it generally causes _EJ0 to be executed for one of the devices in the slot and that may cause its ACPI handle to become invalid. Signed-off-by: Rafael J. Wysocki --- Hi All, This change is not necessary in 3.14-rc (it wouldn't hurt, though), but it closes a (mostly theoretical) race on top of the changes I've queued up for 3.15 in linux-next. Thanks, Rafael --- drivers/pci/hotplug/acpiphp_glue.c | 6 ++++++ 1 file changed, 6 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Index: linux-pm/drivers/pci/hotplug/acpiphp_glue.c =================================================================== --- linux-pm.orig/drivers/pci/hotplug/acpiphp_glue.c +++ linux-pm/drivers/pci/hotplug/acpiphp_glue.c @@ -1007,9 +1007,15 @@ int acpiphp_disable_slot(struct acpiphp_ { int ret; + /* + * Acquire acpi_scan_lock to ensure that the execution of _EJ0 in + * acpiphp_disable_and_eject_slot() will be synchronized properly. + */ + acpi_scan_lock_acquire(); pci_lock_rescan_remove(); ret = acpiphp_disable_and_eject_slot(slot); pci_unlock_rescan_remove(); + acpi_scan_lock_release(); return ret; }