From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932217AbZEAUZ1 (ORCPT ); Fri, 1 May 2009 16:25:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757790AbZEAUZP (ORCPT ); Fri, 1 May 2009 16:25:15 -0400 Received: from fg-out-1718.google.com ([72.14.220.155]:27395 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757449AbZEAUZN (ORCPT ); Fri, 1 May 2009 16:25:13 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=EUSqwN4pAf5//SZe3DeotQsTjkY+qbBJ/xxzFf8E2SrzGGSREN4LEvP/kZx79Tpc+w fcOBWhRo0W+7UAuzsvSIpJm/KTIfLCqgN2dtvhrMmN4t2erRmm4Q0fH3SBfFS+bIw8jG c/Kobl5rh+NNYuXYnhqExMd+GiViSJIQwfWV0= Date: Sat, 2 May 2009 00:25:11 +0400 From: Cyrill Gorcunov To: Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , LKML , Jack Steiner Subject: Re: [PATCH -tip] x86: uv - prevent NULL dereference in uv_system_init Message-ID: <20090501202511.GE4633@lenovo> References: <20090501195638.GC4633@lenovo> <20090501200331.GA2645@elte.hu> <20090501200937.GD4633@lenovo> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090501200937.GD4633@lenovo> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [Cyrill Gorcunov - Sat, May 02, 2009 at 12:09:37AM +0400] | [Ingo Molnar - Fri, May 01, 2009 at 10:03:31PM +0200] | | | | * Cyrill Gorcunov wrote: | | | | > We may reach NULL dereference oops if kmalloc failed. | | > Lets do panic better with sensible message. | | > | | > Signed-off-by: Cyrill Gorcunov | | > --- | | > | | > 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 | | | | Yeah, indeed! I was thinking of __GPF_NOFAIL here as well with | message on top like pr_debug("UV: allocating memory\n") or something | like that. It would make it even cleaner I guess. Hmm? | | -- Cyrill Here is an updated one. -- Cyrill --- From: Cyrill Gorcunov Subject: [PATCH -tip] x86: uv - prevent NULL dereference in uv_system_init We may reach NULL dereference oops if kmalloc failed. Prevent it with explisit BUG_ON. Signed-off-by: Cyrill Gorcunov --- arch/x86/kernel/apic/x2apic_uv_x.c | 3 +++ 1 file changed, 3 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 +584,18 @@ void __init uv_system_init(void) bytes = sizeof(struct uv_blade_info) * uv_num_possible_blades(); uv_blade_info = kmalloc(bytes, GFP_KERNEL); + BUG_ON(!uv_blade_info); get_lowmem_redirect(&lowmem_redir_base, &lowmem_redir_size); bytes = sizeof(uv_node_to_blade[0]) * num_possible_nodes(); uv_node_to_blade = kmalloc(bytes, GFP_KERNEL); + BUG_ON(!uv_node_to_blade); memset(uv_node_to_blade, 255, bytes); bytes = sizeof(uv_cpu_to_blade[0]) * num_possible_cpus(); uv_cpu_to_blade = kmalloc(bytes, GFP_KERNEL); + BUG_ON(!uv_cpu_to_blade); memset(uv_cpu_to_blade, 255, bytes); blade = 0;