Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Rafael J. Wysocki" , Toshi Kani Subject: [ 34/95] ACPI / dock: Take ACPI scan lock in write_undock() Date: Tue, 25 Jun 2013 11:32:21 -0700 Message-Id: <20130625182157.479248242@linuxfoundation.org> In-Reply-To: <20130625182153.605455184@linuxfoundation.org> References: <20130625182153.605455184@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Rafael J. Wysocki" commit 8112006f41fd76ddf4988f8ddd904563db85613c upstream. Since commit 3757b94 (ACPI / hotplug: Fix concurrency issues and memory leaks) acpi_bus_scan() and acpi_bus_trim() must always be called under acpi_scan_lock, but currently the following scenario violating that requirement is possible: write_undock() handle_eject_request() hotplug_dock_devices() dock_remove_acpi_device() acpi_bus_trim() Fix that by making write_undock() acquire acpi_scan_lock before calling handle_eject_request() as appropriate (begin_undock() is under the lock too in analogy with acpi_dock_deferred_cb()). Signed-off-by: Rafael J. Wysocki Acked-by: Toshi Kani Signed-off-by: Greg Kroah-Hartman --- drivers/acpi/dock.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/acpi/dock.c +++ b/drivers/acpi/dock.c @@ -868,8 +868,10 @@ static ssize_t write_undock(struct devic if (!count) return -EINVAL; + acpi_scan_lock_acquire(); begin_undock(dock_station); ret = handle_eject_request(dock_station, ACPI_NOTIFY_EJECT_REQUEST); + acpi_scan_lock_release(); return ret ? ret: count; } static DEVICE_ATTR(undock, S_IWUSR, NULL, write_undock);