From 8fcfb99c8e29c73dd8945b6105ef54ca4eeb171e Mon Sep 17 00:00:00 2001 From: Toshi Kani Date: Tue, 4 Feb 2014 17:48:28 -0700 Subject: 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: [] acpi_device_hotplug+0x10b/0x33b : Call Trace: [] acpi_hotplug_work_fn+0x1c/0x27 [] process_one_work+0x175/0x430 [] 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 Signed-off-by: Rafael J. Wysocki --- drivers/acpi/scan.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 7384158c7f87..57b053f424d1 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -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; -- cgit v1.2.3