From mboxrd@z Thu Jan  1 00:00:00 1970
From: Fernando Lopez-Lezcano <nando@ccrma.Stanford.EDU>
Subject: Re: [ANNOUNCE] 3.2.9-rt15
Date: Mon, 05 Mar 2012 20:15:48 -0800
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Cc: Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-rt-users <linux-rt-users@vger.kernel.org>,
	Clark Williams <clark@redhat.com>,
	"Luis Claudio R. Goncalves" <lclaudio@uudg.org>,
	Fernando Lopez-Lezcano <nando@ccrma.Stanford.EDU>
To: Steven Rostedt <rostedt@goodmis.org>
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On 03/05/2012 02:14 PM, Steven Rostedt wrote:
> Thomas,
>
> Please fold this change into
>
>     cpu-rt-make-hotplug-lock-a-sleeping-spinlock-on-rt.patch

Thanks, this fixed the panic on shutdown I was experiencing!
-- Fernando


> As the patch was never tested (nor even compiled) it introduced a nasty
> bug into taking a CPU down instead of fixing one.
>
> Thanks,
>
> -- Steve
>
> diff --git a/kernel/cpu.c b/kernel/cpu.c
> index c25b5ff..66dfb74 100644
> --- a/kernel/cpu.c
> +++ b/kernel/cpu.c
> @@ -59,16 +59,20 @@ static struct {
>   	int refcount;
>   } cpu_hotplug = {
>   	.active_writer = NULL,
> +#ifdef CONFIG_PREEMPT_RT_FULL
> +	.lock = __SPIN_LOCK_UNLOCKED(cpu_hotplug.lock),
> +#else
>   	.lock = __MUTEX_INITIALIZER(cpu_hotplug.lock),
> +#endif
>   	.refcount = 0,
>   };
>
>   #ifdef CONFIG_PREEMPT_RT_FULL
> -# define hotplug_lock() spin_lock(&cpu_hotplug.lock)
> -# define hotplug_unlock() spin_unlock(&cpu_hotplug.lock)
> +# define hotplug_lock() rt_spin_lock(&cpu_hotplug.lock)
> +# define hotplug_unlock() rt_spin_unlock(&cpu_hotplug.lock)
>   #else
>   # define hotplug_lock() mutex_lock(&cpu_hotplug.lock)
> -# define hotplug_lock() mutex_unlock(&cpu_hotplug.lock)
> +# define hotplug_unlock() mutex_unlock(&cpu_hotplug.lock)
>   #endif
>
>   struct hotplug_pcp {
>
>
> --
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