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Date: Thu, 4 Apr 2013 17:28:10 +0200
From: Christian Ruppert <christian.ruppert@abilis.com>
To: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc: tglx@linutronix.de, Pierrick Hascoet <pierrick.hascoet@abilis.com>,
        Robert Love <rml@tech9.net>, kpreempt-tech@lists.sourceforge.net,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Steven Rostedt <srostedt@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@kernel.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] [PATCH] Gaurantee spinlocks implicit barrier for
 !PREEMPT_COUNT
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Hi Vineet,

Our stress testing campaign has just successfully completed on this
patch. It seems to solve several issues we have seen in unpatched
versions, amongst others the original timer issue, a crash in hrtimer
rb-tree manipulation etc.

Greetings,
  Christian

On Wed, Apr 03, 2013 at 07:41:22PM +0530, Vineet Gupta wrote:
> spinlocks built in a !PREEMPT_COUNT config don't have the compiler
> barrier provided by preempt_* routines. This can break lot of code which
> relies on barrier semantics.
> 
> This manifested as random crashes in timer code when stress testing
> ARC Linux (3.9-rc3): !SMP && !PREEMPT_COUNT
> 
> [...]
> 
> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
> Reported-by: Christian Ruppert <christian.ruppert@abilis.com>
Tested-by: Christian Ruppert <christian.ruppert@abilis.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Christian Ruppert <christian.ruppert@abilis.com>
> Cc: Pierrick Hascoet <pierrick.hascoet@abilis.com>
> Cc: Robert Love <rml@tech9.net>
> Cc: kpreempt-tech@lists.sourceforge.net
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Steven Rostedt <srostedt@redhat.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: linux-kernel@vger.kernel.org
> [...]
-- 
  Christian Ruppert              ,          <christian.ruppert@abilis.com>
                                /|
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