From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935669AbaDJTkz (ORCPT ); Thu, 10 Apr 2014 15:40:55 -0400 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.225]:17273 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S934889AbaDJTky (ORCPT ); Thu, 10 Apr 2014 15:40:54 -0400 Date: Thu, 10 Apr 2014 15:40:51 -0400 From: Steven Rostedt To: Peter Zijlstra Cc: Jiri Olsa , Frederic Weisbecker , Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , linux-kernel@vger.kernel.org Subject: Re: x86: Allow vmalloc faults from NMI context Message-ID: <20140410154051.4d709272@gandalf.local.home> In-Reply-To: <20140410144003.GF13658@twins.programming.kicks-ass.net> References: <20140410144003.GF13658@twins.programming.kicks-ass.net> X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.22; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-RR-Connecting-IP: 107.14.168.142:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 10 Apr 2014 16:40:03 +0200 Peter Zijlstra wrote: > Jiri reported he hit vmalloc_faults()'s: > > WARN_ON_ONCE(in_nmi()); > > The patch that added this ebc8827f75954 ("x86: Barf when vmalloc and > kmemcheck faults happen in NMI") explains that this was done in order to > avoid faults from NMI to cause nested NMIs. > > We have, however, completely fixed this issue and can now safely take > faults from NMI context. > > Therefore remove this warning. We must still leave the kmemcheck warn in > place since kmemcheck itself can't deal with NMI context yet. > Yay, finally.... Link: http://lkml.kernel.org/p/20131015163906.342d8ffa@gandalf.local.home -- Steve > Signed-off-by: Peter Zijlstra > --- > arch/x86/mm/fault.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c > index 8e5722992677..d0234cdf70f1 100644 > --- a/arch/x86/mm/fault.c > +++ b/arch/x86/mm/fault.c > @@ -271,8 +271,6 @@ static noinline __kprobes int vmalloc_fault(unsigned long address) > if (!(address >= VMALLOC_START && address < VMALLOC_END)) > return -1; > > - WARN_ON_ONCE(in_nmi()); > - > /* > * Synchronize this task's top level page-table > * with the 'reference' page table. > @@ -369,8 +367,6 @@ static noinline __kprobes int vmalloc_fault(unsigned long address) > if (!(address >= VMALLOC_START && address < VMALLOC_END)) > return -1; > > - WARN_ON_ONCE(in_nmi()); > - > /* > * Copy kernel mappings over when needed. This can also > * happen within a race in page table update. In the later