From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764711AbZEAUbi (ORCPT ); Fri, 1 May 2009 16:31:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755281AbZEAUb3 (ORCPT ); Fri, 1 May 2009 16:31:29 -0400 Received: from relay3.sgi.com ([192.48.156.57]:38073 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753959AbZEAUb2 (ORCPT ); Fri, 1 May 2009 16:31:28 -0400 Date: Fri, 1 May 2009 15:31:23 -0500 From: Jack Steiner To: Cyrill Gorcunov Cc: Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , LKML Subject: Re: [PATCH -tip] x86: uv - prevent NULL dereference in uv_system_init Message-ID: <20090501203123.GA10878@sgi.com> References: <20090501195638.GC4633@lenovo> <20090501200331.GA2645@elte.hu> <20090501200937.GD4633@lenovo> <20090501202511.GE4633@lenovo> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090501202511.GE4633@lenovo> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, May 02, 2009 at 12:25:11AM +0400, Cyrill Gorcunov wrote: > [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. Acked-by: Jack Steiner > > -- 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;