Re: [PATCH v5 04/13] ima: Introduce per binary measurements list type binary_runtime_size value

On Wed, 2026-05-20 at 22:06 -0400, Mimi Zohar wrote:
> On Wed, 2026-04-29 at 18:03 +0200, Roberto Sassu wrote:
> > From: Roberto Sassu <[email protected]>
> > 
> > Make binary_runtime_size as an array, to have separate counters per binary
> > measurements list type. Currently, define the BINARY type for the existing
> > binary measurements list.
> > 
> > Introduce ima_update_binary_runtime_size() to facilitate updating a
> > binary_runtime_size value with a given binary measurement list type.
> > 
> > Also add the binary measurements list type parameter to
> > ima_get_binary_runtime_size(), to retrieve the desired value. Retrieving
> > the value is now done under the ima_extend_list_mutex, since there can be
> > concurrent updates.
> > 
> > No functional change (except for the mutex usage, that fixes the
> > concurrency issue): the BINARY array element is equivalent to the old
> > binary_runtime_size.
> 
> The patch is really clear and well written, but I don't see a concurrency issue
> requiring taking the ima_extend_list_mutex at least in this patch.

binary_runtime_size is not an atomic variable. It is updated under the
ima_extend_list_mutex lock in ima_add_digest_entry(). The same lock
must be taken on the reader side, ima_get_binary_runtime_size().

Roberto