Just in case, I can't read the code until Wednesday, but...

On 07/06, Christian Brauner wrote:

quoted

send_signal_locked() should not change the caller's siginfo. Make that
part of the type and keep the local rewrite on its copy.

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Bradley Morgan <redacted>

Reviewed-by: Christian Brauner (Amutable) <brauner@kernel.org>

Agreed, but IIRC this change should be rebased on top of -mm tree (I sent
the patch which changes send_signal_locked(), and thanks for your review btw!)

And, again iirc, with that patch "make siginfo const" become really trivial,
we only need to add "const" to every "kernel_siginfo *info" in the
send_signal_locked()'s callchain.

Oleg.