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Date:   Mon, 19 Nov 2018 02:47:04 +0000
From:   Al Viro <viro@ZenIV.linux.org.uk>
To:     Andy Lutomirski <luto@kernel.org>
Cc:     Daniel Colascione <dancol@google.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        Christian Brauner <christian@brauner.io>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        LKML <linux-kernel@vger.kernel.org>,
        "Serge E. Hallyn" <serge@hallyn.com>, Jann Horn <jannh@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Oleg Nesterov <oleg@redhat.com>,
        Aleksa Sarai <cyphar@cyphar.com>,
        Linux FS Devel <linux-fsdevel@vger.kernel.org>,
        Linux API <linux-api@vger.kernel.org>,
        Tim Murray <timmurray@google.com>,
        Kees Cook <keescook@chromium.org>,
        Jan Engelhardt <jengelh@inai.de>
Subject: Re: [PATCH] proc: allow killing processes via file descriptors
Message-ID: <20181119024704.GK32577@ZenIV.linux.org.uk>
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On Sun, Nov 18, 2018 at 09:42:35AM -0800, Andy Lutomirski wrote:

> Now here's the kicker: if the "running program" calls execve(), it
> goes away.  The fd gets some sort of notification that this happened

Type error, parser failed.

Define "fd", please.  If it's a "file descriptor", thank you do playing,
you've lost.  That's not going to work.  If it's "opened file" (aka
"file description" in horrible POSIXese), who's going to get notifications
and what kind of exclusion are you going to use?