netdev - Re: [PATCH 1/2] Revert "af_unix: Fix splice-bind deadlock"

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Date:   Sat, 3 Sep 2016 20:00:13 +0300
From:   Shmulik Ladkani <shmulik.ladkani@...il.com>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Hannes Frederic Sowa <hannes@...essinduktion.org>,
        Rainer Weikusat <rweikusat@...ileactivedefense.com>,
        Eric Dumazet <edumazet@...gle.com>, willy tarreau <w@....eu>,
        netdev@...r.kernel.org
Subject: Re: [PATCH 1/2] Revert "af_unix: Fix splice-bind deadlock"

On Fri, 2 Sep 2016 11:09:23 -0700 (PDT) Linus Torvalds <torvalds@...ux-foundation.org> wrote:
> From: Linus Torvalds <torvalds@...ux-foundation.org>
> Date: Thu, 1 Sep 2016 14:56:49 -0700
> Subject: [PATCH 1/2] Revert "af_unix: Fix splice-bind deadlock"
> 
> This reverts commit c845acb324aa85a39650a14e7696982ceea75dc1.
> 
> It turns out that it just replaces one deadlock with another one: we can
> still get the wrong lock ordering with the readlock due to overlayfs
> calling back into the filesystem layer and still taking the vfs locks
> after the readlock.
> 
> The proper solution ends up being to just split the readlock into two
> pieces: the bind lock (taken *outside* the vfs locks) and the IO lock
> (taken *inside* the filesystem locks).  The two locks are independent
> anyway.
> 
> Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
> ---
> 
> This is not a completely clean revert, because other changes had happened 
> in this area since that commit, but the conflicts were pretty trivial.

Reviewed-by: Shmulik Ladkani <shmulik.ladkani@...il.com>