On Tue, Nov 28, 2023 at 03:07:38PM +0100, Michal Hocko wrote:

On Wed 22-11-23 16:11:54, Gregory Price wrote:
[...]

quoted

+
+	if (!mm)
+		return -ENODEV;

Is this an expected error? No mm means task dying and mm has been
already released. Should we simply return ESRCH wouldbe a better error
code IMO. This should never happen for the current task so it sould be
safe to add.

Hm, good point, and in fact i should make sure that the new pidfd code
is not susceptible to this.

This particular set of lines is not present in the new RFC (not out yet)
but the access to the remote task mm is more controlled via mm_access,
so I would presume that mm_access either returns error, I will make sure
it cannot return null and check for this.

-- 
Michal Hocko
SUSE Labs