[Update][PATCH 3/6] ACPI / hotplug: Fix handle_root_bridge_removal()

From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: ACPI Devel Maling List <linux-acpi@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Linux PCI <linux-pci@vger.kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Toshi Kani <toshi.kani@hp.com>, Yinghai Lu <yinghai@kernel.org>
Subject: [Update][PATCH 3/6] ACPI / hotplug: Fix handle_root_bridge_removal()
Date: Mon, 04 Nov 2013 14:33:09 +0100	[thread overview]
Message-ID: <6808835.gmCqHn1NaE@vostro.rjw.lan> (raw)
In-Reply-To: <2970389.SeMGM45Qln@vostro.rjw.lan>

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

It is required to do get_device() on the struct acpi_device in
question before passing it to acpi_bus_hot_remove_device() through
acpi_os_hotplug_execute(), because acpi_bus_hot_remove_device()
calls acpi_scan_hot_remove() that does put_device() on that
object.

The ACPI PCI root removal routine, handle_root_bridge_removal(),
doesn't do that, which may lead to premature freeing of the
device object or to executing put_device() on an object that
has been freed already.

Fix this problem by making handle_root_bridge_removal() use
get_device() as appropriate.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/pci_root.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Index: linux-pm/drivers/acpi/pci_root.c
===================================================================

--- linux-pm.orig/drivers/acpi/pci_root.c
+++ linux-pm/drivers/acpi/pci_root.c
@@ -608,9 +608,12 @@ static void handle_root_bridge_removal(s
 	ej_event->device = device;
 	ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
 
+	get_device(&device->dev);
 	status = acpi_os_hotplug_execute(acpi_bus_hot_remove_device, ej_event);
-	if (ACPI_FAILURE(status))
+	if (ACPI_FAILURE(status)) {
+		put_device(&device->dev);
 		kfree(ej_event);
+	}
 }
 
 static void _handle_hotplug_event_root(struct work_struct *work)

