Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758810AbaKURTH (ORCPT ); Fri, 21 Nov 2014 12:19:07 -0500 Received: from mail-qa0-f43.google.com ([209.85.216.43]:37491 "EHLO mail-qa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758514AbaKURTD (ORCPT ); Fri, 21 Nov 2014 12:19:03 -0500 MIME-Version: 1.0 In-Reply-To: <20141121170805.GD30603@home.goodmis.org> References: <20141120221122.GA25393@htj.dyndns.org> <20141120230514.GB25393@htj.dyndns.org> <20141120233920.GC25393@htj.dyndns.org> <20141121162742.GB15461@htj.dyndns.org> <20141121170805.GD30603@home.goodmis.org> Date: Fri, 21 Nov 2014 09:19:02 -0800 X-Google-Sender-Auth: GbGLuLUL_zwO9Ofc94jdKIJGcP8 Message-ID: Subject: Re: frequent lockups in 3.18rc4 From: Linus Torvalds To: Steven Rostedt Cc: Andy Lutomirski , Tejun Heo , "linux-kernel@vger.kernel.org" , Thomas Gleixner , Arnaldo Carvalho de Melo , Peter Zijlstra , Frederic Weisbecker , Don Zickus , Dave Jones , "the arch/x86 maintainers" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 21, 2014 at 9:08 AM, Steven Rostedt wrote: > > Actually, in_nmi() is now safe for vmalloc faults. In fact, it handles the > clobbering of the cr2 register just fine. That's not what I object to and find incorrect wrt NMI. Compare the simple and correct 32-bit code to the complex and incorrect 64-bit code. In particular, look at how the 32-bit code relies *entirely* on hardware state. Then look at where the 64-bit code does not. Linus -- 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/