Message-ID: <1379225343.5545.154.camel@marge.simpson.net>
Subject: Re: [PATCH 1/2] ipc/sem.c: Race in sem_lock()
From: Mike Galbraith <efault@gmx.de>
To: Manfred Spraul <manfred@colorfullife.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>, Rik van Riel <riel@redhat.com>,
        Davidlohr Bueso <davidlohr.bueso@hp.com>, hhuang@redhat.com
Date: Sun, 15 Sep 2013 08:09:03 +0200
In-Reply-To: <1379194496-4642-1-git-send-email-manfred@colorfullife.com>
References: <1379194496-4642-1-git-send-email-manfred@colorfullife.com>
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On Sat, 2013-09-14 at 23:34 +0200, Manfred Spraul wrote:

> The bug is probably also present in 3.10 and 3.11, but for these kernels
> is is probably simpler just to move the test of sma->complex_count after
> the spin_is_locked() test.

IMHO, your 6 patch series should go to stable as well.  Scalability is
still BAD without them.  Now, you've shown the lock split to be buggy.

Logically, the whole thing should be reverted entirely in stable, or
fixed up properly.  Humongous improvements will find their way into
every long term stable kernel on the planet regardless, so..

Stable may as well do the Borg thing, resistance really is futile ;-)

-Mike

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