Re: WARNING in do_notify_parent (kernel/signal.c:2174)

[y2k]

Follow-up: I found that commit 0f8e38eeb995 by Oleg Nesterov
("do_notify_parent: sanitize the valid_signal() checks") appears to be
related to this WARNING.

The syzkaller reproducer confirms the WARN_ON_ONCE fires in real
conditions via syz_clone() with specific arguments.

Kernel tested: 7.1.0-rc2-00099-gadc1e5c6203c

Thanks,
y2k
y2k@xxxxxxxxxxxxxxxxx