From: Oleg Nesterov <oleg@redhat.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Jeff Layton <jlayton@kernel.org>,
viro@zeniv.linux.org.uk, berrange@redhat.com,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v3 3/3] exec: do unshare_files after de_thread
Date: Mon, 17 Sep 2018 17:28:17 +0200 [thread overview]
Message-ID: <20180917152817.GB25173@redhat.com> (raw)
In-Reply-To: <87efdttmjm.fsf@xmission.com>
On 09/16, Eric W. Biederman wrote:
>
> Oleg Nesterov <oleg@redhat.com> writes:
>
> > IOW. Lets ignore do_close_on_exec(), lets ignore the fact that unshare_fd()
> > can fail and thus it makes sense to call it before point-of-no-return.
> >
> > Any other reason why we can't simply call unshare_files() at the end of
> > __do_execve_file() on success?
>
> The reason we call we call unshare_files is in case the files are shared
> with another process. AKA old style linux threads, or someone being
> clever. In that case we need a private copy of files for close on exec
> because we should not close the files of the other process that has not
> called exec.
This is clear,
> The only reason for calling unshare_files before the point of no return
> is so that we can get a good error message to the calling process if
> unshare_files fails.
OK, so you too think there are no other reasons.
> AKA it would be reasonable to move unshare_files to just above
> do_close_on_exec in flush_old_exec. We could further make the
> unshare_files not return displaced and just drop it.
Yes, this is exactly what I had in mind.
Oleg.
next prev parent reply other threads:[~2018-09-17 15:28 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-14 10:53 [PATCH v3 0/3] exec: fix passing of file locks across execve in multithreaded processes Jeff Layton
2018-09-14 10:53 ` [PATCH v3 1/3] exec: separate thread_count for files_struct Jeff Layton
2018-09-15 16:04 ` Oleg Nesterov
2018-09-16 16:10 ` Eric W. Biederman
2018-09-17 15:24 ` Oleg Nesterov
2018-09-17 20:45 ` Eric W. Biederman
2018-09-14 10:53 ` [PATCH v3 2/3] exec: delay clone(CLONE_FILES) if task associated with current files_struct is exec'ing Jeff Layton
2018-09-14 10:53 ` [PATCH v3 3/3] exec: do unshare_files after de_thread Jeff Layton
2018-09-15 16:37 ` Oleg Nesterov
2018-09-16 16:49 ` Eric W. Biederman
2018-09-17 15:28 ` Oleg Nesterov [this message]
2018-09-16 16:59 ` Eric W. Biederman
2018-09-16 17:38 ` [RFC][PATCH 0/3] exec: Moving unshare_files_struct Eric W. Biederman
2018-09-16 17:39 ` [RFC][PATCH 1/3] exec: Move unshare_files down to avoid locks being dropped on exec Eric W. Biederman
2018-09-17 15:49 ` Oleg Nesterov
2018-09-16 17:40 ` [RFC][PATCH 2/3] exec: Simplify unshare_files Eric W. Biederman
2018-09-17 16:23 ` Oleg Nesterov
2018-09-17 20:26 ` Eric W. Biederman
2018-09-16 17:41 ` [RFC][PATCH 3/3] exec: Remove reset_files_struct Eric W. Biederman
2018-09-17 15:59 ` [RFC][PATCH 0/3] exec: Moving unshare_files_struct Oleg Nesterov
2018-09-18 22:18 ` Eric W. Biederman
2018-09-17 16:24 ` Jeff Layton
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