On Mon, 2019-12-16 at 15:53 +0900, James Bottomley wrote: > That doesn't matter ... the question is, is the input assumption that > both pre/post have to be called or neither must correct? If so, the > code is wrong, if not, explain why. Thanks, James, for looking at the locking. "ima_process_keys" is set once. Once it is set, the keys are measured immediately. For performance to avoid taking the mutex, both the reader and writer check "ima_process_keys" twice, once without taking the lock and, again, after taking the lock. Based on the second test, the reader queues the "key" or not. Refer to ima_queue_key(). The latest patch version sets "ima_process_keys" after taking the lock. With this change, the comment in ima_process_queued_keys() is now correct. We're now guaranteed to process the queued "keys" just once and not drop any "key" measurements. I hope this answers your question. Mimi
