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Date:   Mon, 19 Nov 2018 11:54:26 +0100
From:   Pavel Machek <pavel@ucw.cz>
To:     Daniel Colascione <dancol@google.com>
Cc:     linux-kernel@vger.kernel.org, rppt@linux.ibm.com,
        timmurray@google.com, joelaf@google.com, surenb@google.com,
        Jonathan Corbet <corbet@lwn.net>,
        Andrew Morton <akpm@linux-foundation.org>,
        Roman Gushchin <guro@fb.com>,
        Mike Rapoport <rppt@linux.vnet.ibm.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        "Dennis Zhou (Facebook)" <dennisszhou@gmail.com>,
        Prashant Dhamdhere <pdhamdhe@redhat.com>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>
Subject: Re: [PATCH v2] Document /proc/pid PID reuse behavior
Message-ID: <20181119105426.GD28607@amd>
References: <20181031150625.147369-1-dancol@google.com>
 <20181105132205.138695-1-dancol@google.com>
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On Mon 2018-11-05 13:22:05, Daniel Colascione wrote:
> State explicitly that holding a /proc/pid file descriptor open does
> not reserve the PID. Also note that in the event of PID reuse, these
> open file descriptors refer to the old, now-dead process, and not the
> new one that happens to be named the same numeric PID.
>=20
> Signed-off-by: Daniel Colascione <dancol@google.com>
> ---
>  Documentation/filesystems/proc.txt | 7 +++++++
>  1 file changed, 7 insertions(+)
>=20
> Moved paragraphed to start of /proc/pid section; added signed-off-by.
>=20
> diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesyste=
ms/proc.txt
> index 12a5e6e693b6..0b14460f721d 100644
> --- a/Documentation/filesystems/proc.txt
> +++ b/Documentation/filesystems/proc.txt
> @@ -125,6 +125,13 @@ process running on the system, which is named after =
the process ID (PID).
>  The link  self  points  to  the  process reading the file system. Each p=
rocess
>  subdirectory has the entries listed in Table 1-1.
> =20
> +Note that an open a file descriptor to /proc/<pid> or to any of its
> +contained files or subdirectories does not prevent <pid> being reused
> +for some other process in the event that <pid> exits. Operations on

"does not" -> "may not"?

We want to leave this unspecified, so that we can change it in future.
									Pavel


--=20
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo=
g.html

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