Re: [PATCH v5 1/2] IMA: Define workqueue for early boot "key" measurements

From: Mimi Zohar
Date: Fri Dec 20 2019 - 07:53:18 EST


On Thu, 2019-12-19 at 08:55 -0800, Lakshmi Ramasubramanian wrote:
> I am not sure if the mutex can be removed.
>
> In ima_queue_key() we need to test the flag and add the key to the list
> as an atomic operation:
>
> if (!test_bit())
> insert_key_to_list
>
> Suppose the if condition is true, but before we could insert the key to
> the list, ima_process_queued_keys() runs and processes queued keys we'll
> add the key to the list and never process it.
>
> Is there an API in the kernel to test and add an entry to a list
> atomically?

Ok, using test_and_set_bit() and test_bit() only helps, if we can get
rid of the mutex. ÂI'll queue these patches.

thanks,

Mimi