From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta8.messagelabs.com (mail6.bemta8.messagelabs.com [216.82.243.55]) by kanga.kvack.org (Postfix) with ESMTP id A759E6B00A5 for ; Tue, 22 Nov 2011 16:58:18 -0500 (EST) Message-ID: <1321999085.14573.2.camel@pasglop> Subject: Re: WARNING: at mm/slub.c:3357, kernel BUG at mm/slub.c:3413 From: Benjamin Herrenschmidt Date: Wed, 23 Nov 2011 08:58:05 +1100 In-Reply-To: <1321948113.27077.24.camel@edumazet-laptop> References: <20111121131531.GA1679@x4.trippels.de> <1321884966.10470.2.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <20111121153621.GA1678@x4.trippels.de> <1321890510.10470.11.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <20111121161036.GA1679@x4.trippels.de> <1321894353.10470.19.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <1321895706.10470.21.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <20111121173556.GA1673@x4.trippels.de> <1321900743.10470.31.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <20111121185215.GA1673@x4.trippels.de> <20111121195113.GA1678@x4.trippels.de> <1321907275.13860.12.camel@pasglop> <1321948113.27077.24.camel@edumazet-laptop> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Eric Dumazet Cc: Christoph Lameter , Christian Kujau , Markus Trippelsdorf , "Alex,Shi" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , Pekka Enberg , Matt Mackall , "netdev@vger.kernel.org" , Tejun Heo On Tue, 2011-11-22 at 08:48 +0100, Eric Dumazet wrote: > Le lundi 21 novembre 2011 A 21:18 -0600, Christoph Lameter a A(C)crit : > > > Hmmm... That means that c->page points to page not frozen. Per cpu > > partial pages are frozen until they are reused or until the partial list > > is flushed. > > > > Does this ever happen on x86 or only on other platforms? In put_cpu_partial() the > > this_cpu_cmpxchg really needs really to be irq safe. this_cpu_cmpxchg is > > only preempt safe. > > > > Index: linux-2.6/mm/slub.c > > =================================================================== > > --- linux-2.6.orig/mm/slub.c 2011-11-21 21:15:41.575673204 -0600 > > +++ linux-2.6/mm/slub.c 2011-11-21 21:16:33.442336849 -0600 > > @@ -1969,7 +1969,7 @@ > > page->pobjects = pobjects; > > page->next = oldpage; > > > > - } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage); > > + } while (irqsafe_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage); > > stat(s, CPU_PARTIAL_FREE); > > return pobjects; > > } > > > > For x86, I wonder if our !X86_FEATURE_CX16 support is correct on SMP > machines. > > this_cpu_cmpxchg16b_emu() claims to be IRQ safe, but may be buggy... > > Could we have somewhere a NMI handler calling kmalloc() ? Christian and I are on ppc, which uses the generic implementation of this_cpu_cmpxchg() which is not irq safe. So the above patch is needed regardless. Christian, can you try it see if that helps in your case ? Cheers, Ben. -- 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