On 07/10, Kees Cook wrote:

This adds the ability for threads to request seccomp filter
synchronization across their thread group (at filter attach time).
For example, for Chrome to make sure graphic driver threads are fully
confined after seccomp filters have been attached.

To support this, locking on seccomp changes via thread-group-shared
sighand lock is introduced, along with refactoring of no_new_privs. Races
with thread creation are handled via delayed duplication of the seccomp
task struct field and cred_guard_mutex.

This includes a new syscall (instead of adding a new prctl option),
as suggested by Andy Lutomirski and Michael Kerrisk.

I do not not see any problems in this version,

Reviewed-by: Oleg Nesterov <oleg@redhat.com>