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Date:   Thu, 25 Jul 2019 12:16:27 +0200
From:   Oleg Nesterov <oleg@redhat.com>
To:     Christian Brauner <christian@brauner.io>
Cc:     linux-kernel@vger.kernel.org, arnd@arndb.de, ebiederm@xmission.com,
        keescook@chromium.org, joel@joelfernandes.org, tglx@linutronix.de,
        tj@kernel.org, dhowells@redhat.com, jannh@google.com,
        luto@kernel.org, akpm@linux-foundation.org, cyphar@cyphar.com,
        torvalds@linux-foundation.org, viro@zeniv.linux.org.uk,
        kernel-team@android.com, linux-api@vger.kernel.org
Subject: Re: [PATCH 2/5] pidfd: add pidfd_wait()
Message-ID: <20190725101626.GD4707@redhat.com>
References: <20190724144651.28272-1-christian@brauner.io>
 <20190724144651.28272-3-christian@brauner.io>
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On 07/24, Christian Brauner wrote:
>
> +SYSCALL_DEFINE6(pidfd_wait, int, pidfd, int __user *, stat_addr,
> +		siginfo_t __user *, info, struct rusage __user *, ru,
> +		unsigned int, states, unsigned int, flags)
> +{

Oh, I too think that P_PIDFD makes more sense.

and could you explain in the changelog why? I am not arguing and if
nothing else this is consistent with other pidfd features, but if you
are parent/debugger you can't hit the problem with pid-reuse, unless
you races with your sub-threads.

Oleg.