On 08/16/12 01:35, Chanho Min wrote: >> functions will occur in line. I also don't see why the sdev reference >> couldn't drop to zero here. > scsi_request_fn is called under the lock of request_queue->queue_lock. > If we drop the sdev reference to zero here, > scsi_device_dev_release_usercontext is > invoked and make request_queue to NULL. When caller of scsi_request_fn try to > unlock request_queue->queue_lock, the oops is occurred. Whether or not your patch is applied, if the put_device() call in scsi_request_fn() decreases the sdev reference count to zero, the scsi_request_fn() caller will still try to unlock the queue lock after scsi_request_fn() finished and hence will trigger a use-after-free. I'm afraid the only real solution is to modify the SCSI and/or block layers such that scsi_remove_device() can't finish while scsi_request_fn() is in progress. And once that is guaranteed the get_device() / put_device() pair can be left out from scsi_request_fn(). Bart. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
