From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stanislav Meduna Subject: Re: [PATCH] mm: fix up a spurious page fault whenever it happens Date: Wed, 19 Jun 2013 09:36:39 +0200 Message-ID: <51C15F87.20100@meduna.org> References: <5195ED8B.7060002@meduna.org> <1369183168.6828.168.camel@gandalf.local.home> <519CBB30.3060200@redhat.com> <20130522134111.33a695c5@cuia.bos.redhat.com> <519D08B0.8050707@meduna.org> <1369246316.6828.176.camel@gandalf.local.home> <519D0CAB.7020800@meduna.org> <519D0FF8.5080200@redhat.com> <519D118B.6010306@zytor.com> <519D11BF.5000604@redhat.com> <519DCE2A.4010801@meduna.org> <519E095A.4000105@redhat.com> <519F24DD.5060700@meduna.org> <519F65DB.2020305@redhat.com> <51BE2F5C.8070408@meduna.org> <51C0B177.2000006@meduna.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Rik van Riel , "H. Peter Anvin" , Steven Rostedt , "linux-rt-users@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Thomas Gleixner , Ingo Molnar , the arch/x86 maintainers , Hai Huang , Peter Zijlstra To: Linus Torvalds Return-path: Received: from www.meduna.org ([92.240.244.38]:44467 "EHLO meduna.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755576Ab3FSHgy (ORCPT ); Wed, 19 Jun 2013 03:36:54 -0400 In-Reply-To: Sender: linux-rt-users-owner@vger.kernel.org List-ID: On 19.06.2013 07:20, Linus Torvalds wrote: >> No crash in 2 days running with preempt none... > > Is this UP? Yes it is. > There's the fast_tlb race that Peter fixed in commit 29eb77825cc7 > ("arch, mm: Remove tlb_fast_mode()"). I'm not seeing how it would > cause infinite TLB faults, but it definitely causes potentially > incoherent TLB contents. And afaik it only happens with > CONFIG_PREEMPT, and on UP systems. Which sounds like it might match > your setup... Oh, thank you for the pointer, this indeed looks interesting. Unfortunately the patch massively does not apply to 3.4 which I am using and I know too little what all is involved here to backport it. I will test it when (if) it gets to the 3.4(-rt) (or when I find some spare time to play with the newer kernel on that system). Thanks -- Stano