From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id 3F7686B0099 for ; Tue, 22 Nov 2011 14:32:36 -0500 (EST) Date: Tue, 22 Nov 2011 20:32:31 +0100 From: Markus Trippelsdorf Subject: Re: slub: Lockout validation scans during freeing of object Message-ID: <20111122193231.GB1627@x4.trippels.de> References: <1321982484.18002.6.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <20111122185540.GA1627@x4.trippels.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Eric Dumazet , Christian Kujau , Benjamin Herrenschmidt , "Alex,Shi" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , Pekka Enberg , Matt Mackall , "netdev@vger.kernel.org" , Tejun Heo On 2011.11.22 at 13:20 -0600, Christoph Lameter wrote: > On Tue, 22 Nov 2011, Markus Trippelsdorf wrote: > > > On 2011.11.22 at 11:40 -0600, Christoph Lameter wrote: > > > On Tue, 22 Nov 2011, Eric Dumazet wrote: > > > > > > > This seems better, but I still have some warnings : > > > > > > Trying to reproduce with a kernel configured to do preempt. This is > > > actually quite interesting since its always off by 1. > > > > BTW there are some obvious overflows in the "slabinfo -l" output on my machine: > > Could you get me the value of the "slabs" field for the slabs showing the > wierd values. I.e. do > > cat /sys/kernel/slab/signal_cache/slabs > > > signal_cache 268 920 360.4K 18446744073709551614/7/24 17 2 31 68 A > It's quite easy to explain. You're using unsigned ints in: snprintf(dist_str, 40, "%lu/%lu/%d", s->slabs - s->cpu_slabs, s->partial, s->cpu_slabs); and (s->slabs - s->cpu_slabs) can get negative. For example: task_struct 269 1504 557.0K 18446744073709551601/5/32 21 3 29 72 Here s-slabs is 17 and s->cpu_slabs is 32. That gives: 17-32=18446744073709551601. -- Markus -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org