On Wednesday 17 of October 2012 07:55:42 Toshi Kani wrote:

On Wed, 2012-10-17 at 10:25 +0900, Yasuaki Ishimatsu wrote:

quoted

2012/10/16 1:34, Toshi Kani wrote:

quoted

During hot-remove, acpi_bus_hot_remove_device() calls ACPI _LCK
method when device->flags.lockable is set. However, this device
pointer is stale since the target acpi_device object has been
already kfree'd by acpi_bus_trim().

The flags.lockable indicates whether or not this ACPI object
implements _LCK method. Fix the stable pointer access by replacing
it with acpi_get_handle() to check if _LCK is implemented.

Signed-off-by: Toshi Kani <redacted>

Looks good to me.
Reviewed-by: Yasuaki Ishimatsu <redacted>

Thanks Yasuaki for reviewing!

Applied to linux-pm.git/linux-next as v3.8 material.

Thanks,
Rafael

quoted

quoted

---
  drivers/acpi/scan.c | 6 +++++-
  1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 1fcb867..ed87f43 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c

@@ -97,6 +97,7 @@ void acpi_bus_hot_remove_device(void *context)
  	struct acpi_eject_event *ej_event = (struct acpi_eject_event *) context;
  	struct acpi_device *device;
  	acpi_handle handle = ej_event->handle;
+	acpi_handle temp;
  	struct acpi_object_list arg_list;
  	union acpi_object arg;
  	acpi_status status = AE_OK;

@@ -117,13 +118,16 @@ void acpi_bus_hot_remove_device(void *context)
  		goto err_out;
  	}
  
+	/* device has been freed */
+	device = NULL;
+
  	/* power off device */
  	status = acpi_evaluate_object(handle, "_PS3", NULL, NULL);
  	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND)
  		printk(KERN_WARNING PREFIX
  				"Power-off device failed\n");
  
-	if (device->flags.lockable) {
+	if (ACPI_SUCCESS(acpi_get_handle(handle, "_LCK", &temp))) {
  		arg_list.count = 1;
  		arg_list.pointer = &arg;
  		arg.type = ACPI_TYPE_INTEGER;

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.