Commit 8fcfb99c authored Feb 04, 2014 by Toshi Kani Committed by Rafael J. Wysocki Feb 05, 2014

ACPI / hotplug: Fix panic on eject to ejected device



When an eject request is sent to an ejected ACPI device, the following
panic occurs:

 ACPI: \_SB_.SCK3.CPU3: ACPI_NOTIFY_EJECT_REQUEST event
 BUG: unable to handle kernel NULL pointer dereference at 0000000000000070
 IP: [<ffffffff813a7cfe>] acpi_device_hotplug+0x10b/0x33b
	:
 Call Trace:
 [<ffffffff813a24da>] acpi_hotplug_work_fn+0x1c/0x27
 [<ffffffff8109cbe5>] process_one_work+0x175/0x430
 [<ffffffff8109d7db>] worker_thread+0x11b/0x3a0

This is becase device->handler is NULL in acpi_device_hotplug().
This case was used to fail in acpi_hotplug_notify_cb() as the target
had no acpi_deivce.  However, acpi_device now exists after ejection.

Added a check to verify if acpi_device->handler is valid for an
eject request in acpi_hotplug_notify_cb().  Note that handler passed
from an argument is still valid while acpi_device->handler is NULL.

Fixes: 202317a5 (ACPI / scan: Add acpi_device objects for all device nodes in the namespace)
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent 38dbfb59

drivers/acpi/scan.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -484,7 +484,6 @@ static void acpi_device_hotplug(void *data, u32 src)
		static void acpi_hotplug_notify_cb(acpi_handle handle, u32 type, void *data)
		{
		u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
		struct acpi_scan_handler *handler = data;
		struct acpi_device *adev;
		acpi_status status;

		@@ -500,7 +499,10 @@ static void acpi_hotplug_notify_cb(acpi_handle handle, u32 type, void *data)
		break;
		case ACPI_NOTIFY_EJECT_REQUEST:
		acpi_handle_debug(handle, "ACPI_NOTIFY_EJECT_REQUEST event\n");
		if (!handler->hotplug.enabled) {
		if (!adev->handler)
		goto err_out;

		if (!adev->handler->hotplug.enabled) {
		acpi_handle_err(handle, "Eject disabled\n");
		ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
		goto err_out;

Admin message