Re: [PATCH v2] Document /proc/pid PID reuse behavior

Pavel Machek
2018-11-19T10:54:31Z

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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.
>
> Signed-off-by: Daniel Colascione <dancol@google.com>
> ---
> Documentation/filesystems/proc.txt | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> Moved paragraphed to start of /proc/pid section; added signed-off-by.
>
> diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/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 process
> subdirectory has the entries listed in Table 1-1.
>
> +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

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