From: Jeff Layton <jlayton@kernel.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: viro@zeniv.linux.org.uk, berrange@redhat.com,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Oleg Nesterov <oleg@redhat.com>
Subject: Re: [RFC][PATCH 0/3] exec: Moving unshare_files_struct
Date: Mon, 17 Sep 2018 12:24:57 -0400 [thread overview]
Message-ID: <c7e4a674b86760e7878aa8dc66988f38db235ec3.camel@kernel.org> (raw)
In-Reply-To: <87a7ohs5ow.fsf@xmission.com>
On Sun, 2018-09-16 at 19:38 +0200, Eric W. Biederman wrote:
> Paired with Oleg's patch to reduce the number of callers of
> get_files_struct it looks like we can simplify the basic idea of moving
> unshare_files in exec by quite a bit so that in net we have fewer lines
> of code.
>
> The big simplification from Jeff's verion is that we take advantage
> of calling unshare_files past the point of no return. Which removes
> the need for cleanup, and restoring ->files. Which removes the
> need for blocking clone and unshare.
>
> Oleg's patch to remove get_files_struct from proc means we don't need
> two counts in files_struct.
>
> Which leaves us with the question of what are the races in fs/exec.c
> with respect to accessing files. Semantically I don't think we care
> but we do need to be certain the implementation of exec is still robust.
>
> These patches are still rough and ready and only compile tested but I
> believe they demonstrate what is possible.
>
> Eric W. Biederman (3):
> exec: Move unshare_files down to avoid locks being dropped on exec.
> exec: Simplify unshare_files
> exec: Remove reset_files_struct
>
> fs/coredump.c | 5 +----
> fs/exec.c | 16 +++++-----------
> fs/file.c | 12 ------------
> include/linux/fdtable.h | 3 +--
> kernel/fork.c | 12 ++++++------
> 5 files changed, 13 insertions(+), 35 deletions(-)
>
> Eric
Much better than what I had proposed and I do like that diffstat. You
can add this from me too:
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Maybe get this into -next soon once it has passed some sanity tests?
Thanks,
--
Jeff Layton <jlayton@kernel.org>
prev parent reply other threads:[~2018-09-17 21:53 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
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 [this message]
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