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Date: Fri, 1 May 2009 22:03:31 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>,
       LKML <linux-kernel@vger.kernel.org>, Jack Steiner <steiner@sgi.com>
Subject: Re: [PATCH -tip] x86: uv - prevent NULL dereference in
	uv_system_init
Message-ID: <20090501200331.GA2645@elte.hu>
References: <20090501195638.GC4633@lenovo>
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* Cyrill Gorcunov <gorcunov@openvz.org> wrote:

> We may reach NULL dereference oops if kmalloc failed.
> Lets do panic better with sensible message.
> 
> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
> ---
> 
> Actually there is a dubious place as well at early_get_nodeid.
> Is there a guarantee that we _never_ fail in early_ioremap?
> 
>  arch/x86/kernel/apic/x2apic_uv_x.c |    9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> Index: linux-2.6.git/arch/x86/kernel/apic/x2apic_uv_x.c
> =====================================================================
> --- linux-2.6.git.orig/arch/x86/kernel/apic/x2apic_uv_x.c
> +++ linux-2.6.git/arch/x86/kernel/apic/x2apic_uv_x.c
> @@ -584,15 +584,21 @@ void __init uv_system_init(void)
>  
>  	bytes = sizeof(struct uv_blade_info) * uv_num_possible_blades();
>  	uv_blade_info = kmalloc(bytes, GFP_KERNEL);
> +	if (!uv_blade_info)
> +		goto err_nomem;

hm, i think a BUG_ON() might be shorter and more appropriate here. 
We really shouldnt be running out of memory during system init.

	Ingo