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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	rostedt@goodmis.org, tglx@linutronix.de,
	paulmck@linux.vnet.ibm.com, linux-rt-users@vger.kernel.org,
	kernel@pengutronix.de
Subject: Re: [PATCH rt] fix "list_bl.h: make list head locking RT safe" for !SMP && !DEBUG_SPINLOCK
Date: Tue, 09 Jul 2013 09:39:14 +0200	[thread overview]
Message-ID: <51DBBE22.8060403@linutronix.de> (raw)
In-Reply-To: <51DB40BA.60607@windriver.com>

On 07/09/2013 12:44 AM, Paul Gortmaker wrote:
> On 13-07-08 06:26 PM, Uwe Kleine-König wrote:
>> and so depending on LIST_BL_LOCKMASK being one. But LIST_BL_LOCKMASK is
>> only one if at least on of CONFIG_SMP and CONFIG_DEBUG_SPINLOCK are
>> defined. Without these the value returned by hlist_bl_first has the
>> zeroth bit set which likely results in a crash.
> 
> The incorrect assumption that I made was that the bit spin locks
> still set/cleared the bit in the !SMP case.  So if we set the bit
> and the mask is zero, we get the mismatch, giving something like:
> 
> Acked-by: Paul Gortmaker <paul.gortmaker@windriver.com>
> Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>

Thanks everyone.

> 
> Thanks,
> Paul.

Sebastian
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      reply	other threads:[~2013-07-09  7:39 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-08 22:26 [PATCH rt] fix "list_bl.h: make list head locking RT safe" for !SMP && !DEBUG_SPINLOCK Uwe Kleine-König
2013-07-08 22:44 ` Paul Gortmaker
2013-07-09  7:39   ` Sebastian Andrzej Siewior [this message]

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