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Date: Thu, 8 Feb 2024 15:06:10 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Christian Brauner <brauner@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Tycho Andersen <tycho@tycho.pizza>, linux-api@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] pidfd: change pidfd_send_signal() to respect PIDFD_THREAD
Message-ID: <20240208140610.GE19801@redhat.com>
References: <20240207114549.GA12697@redhat.com>
 <20240208-fragt-prospekt-7866333b15f0@brauner>
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On 02/08, Christian Brauner wrote:
>
> I would also suggest we update the obsolete comment on top of
> pidfd_send_signal() along the lines of:

Yes, but...

> + * If the @pidfd refers to a thread-group leader the signal is thread-group
> + * directed. If @pidfd referes to a thread then the signal is thread directed.

No, this depends on PIDFD_THREAD only.

If it is set then the signal is always "thread directed" even if @pidfd refers
to a thread-group leader.

Otherwise the target task must be a group leader and the signal will be
"thread-group directed".

Right?

Oleg.