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ACPI / hotplug: Fix panic on eject to ejected device

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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: 202317a573b2 (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>
This commit is contained in:
Toshi Kani 2014-02-04 17:48:28 -07:00 committed by Rafael J. Wysocki
parent 38dbfb59d1
commit 8fcfb99c8e
1 changed files with 4 additions and 2 deletions
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6
drivers/acpi/scan.c
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@ -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;