Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756512AbYFFOH2 (ORCPT ); Fri, 6 Jun 2008 10:07:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754752AbYFFOHM (ORCPT ); Fri, 6 Jun 2008 10:07:12 -0400 Received: from rv-out-0506.google.com ([209.85.198.224]:21762 "EHLO rv-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751827AbYFFOHK (ORCPT ); Fri, 6 Jun 2008 10:07:10 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=rK+9Le12xYPRHZqILfEv5fjty3VnA2XBP/kYR9ffzoGLgAuUvRmXkkyu5SqZPSxBZZ uNrJIaJOtlqWHQYf5W02AYmN/+OJhHsyQU1Q3+tCEl27lk4kVkgO1S4pTt4LyEVVF5GB dvsDBp6YtdHDz2vpUcqZTbX3dALS25HHjrcLo= Message-ID: <19f34abd0806060707x7570c835u4b1837b54dfa36ba@mail.gmail.com> Date: Fri, 6 Jun 2008 16:07:09 +0200 From: "Vegard Nossum" To: "Mike Travis" Subject: Re: linux-next: Tree for June 5 Cc: "Ingo Molnar" , "Andrew Morton" , "Stephen Rothwell" , linux-next@vger.kernel.org, LKML In-Reply-To: <19f34abd0806060650q203bef48rd3b20c0cabec4774@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080605175217.cee497f3.sfr@canb.auug.org.au> <20080605195604.41623687.akpm@linux-foundation.org> <20080606071707.GB9708@elte.hu> <20080606002957.6329a0ec.akpm@linux-foundation.org> <20080606024811.70db9ab2.akpm@linux-foundation.org> <20080606035413.37f340ef.akpm@linux-foundation.org> <20080606115759.GA29321@elte.hu> <19f34abd0806060533x6d3ff66tc29306143103fc40@mail.gmail.com> <48493CBD.1000202@sgi.com> <19f34abd0806060650q203bef48rd3b20c0cabec4774@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2933 Lines: 86 On Fri, Jun 6, 2008 at 3:50 PM, Vegard Nossum wrote: > On Fri, Jun 6, 2008 at 3:33 PM, Mike Travis wrote: >> Vegard Nossum wrote: >>> >>> I reproced it with gc 4.1.2. I think the error is somewhere in kernel/sched.c. >>> >>> static int __build_sched_domains(const cpumask_t *cpu_map, >>> struct sched_domain_attr *attr) >>> { >>> ... >>> for (i = 0; i < MAX_NUMNODES; i++) { >>> ... >>> sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i); >>> ... >>> >>> This code is calling into the allocator with a spurious value of i, >>> which causes SLAB to use an index (of 4 in my case) that is out of >>> bounds for its nodelist array (at least it hasn't been initialized). >>> >>> This bit of code (a bit further down, inside the same loop) is also dubious: >>> >>> sg = kmalloc_node(sizeof(struct sched_group), >>> GFP_KERNEL, i); >>> if (!sg) { >>> printk(KERN_WARNING >>> "Can not alloc domain group for node %d\n", j); >>> goto error; >>> } >>> >>> Where it passes i to kmalloc_node() but reports an allocation for node >>> j. Which one is correct? >>> > > Hm, I think I'm wrong and the code is correct. However... > >>> Hope this helps, will send an update if I find out more. >>> >>> >>> Vegard >>> >> >> Thanks Vegard for tracking this down. My thoughts were along the same >> wavelength... ;-) ... > > This is a P4 3.0GHz with 1 physical CPU (but HT, so two logical CPUs). > Yet node 4 is claimed to have a cpu too. That's bogus! > > (But I don't think it's an error in sched.c any more, probably the > code that sets up the node maps.) Aha. The error is of course that the node masks for nodes > nr_node_ids are not valid. While this function ignores that: cpumask_t *_node_to_cpumask_ptr(int node) { if (node_to_cpumask_map == NULL) { printk(KERN_WARNING "_node_to_cpumask_ptr(%d): no node_to_cpumask_map!\n", node); dump_stack(); return &cpu_online_map; } return &node_to_cpumask_map[node]; } EXPORT_SYMBOL(_node_to_cpumask_ptr); Notice the return statement. It needs to check if node < nr_node_ids. Vegard -- "The animistic metaphor of the bug that maliciously sneaked in while the programmer was not looking is intellectually dishonest as it disguises that the error is the programmer's own creation." -- E. W. Dijkstra, EWD1036 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/