Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757594AbaKTXej (ORCPT ); Thu, 20 Nov 2014 18:34:39 -0500 Received: from mail-qg0-f41.google.com ([209.85.192.41]:55966 "EHLO mail-qg0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756779AbaKTXei (ORCPT ); Thu, 20 Nov 2014 18:34:38 -0500 MIME-Version: 1.0 In-Reply-To: References: <20141119190215.GA10796@lerouge> <20141119225615.GA11386@lerouge> <20141119235033.GE11386@lerouge> <20141120122339.GA14877@htj.dyndns.org> <20141120221122.GA25393@htj.dyndns.org> <20141120230514.GB25393@htj.dyndns.org> Date: Thu, 20 Nov 2014 15:34:37 -0800 X-Google-Sender-Auth: SIxhfM4nljciq4kGwtL3oRrG1ac Message-ID: Subject: Re: frequent lockups in 3.18rc4 From: Linus Torvalds To: Andy Lutomirski Cc: Tejun Heo , Thomas Gleixner , Frederic Weisbecker , Dave Jones , Don Zickus , Linux Kernel , "the arch/x86 maintainers" , Peter Zijlstra , Arnaldo Carvalho de Melo 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 Thu, Nov 20, 2014 at 3:08 PM, Andy Lutomirski wrote: > > What's the issue with nmi? Page faults are supposed to nest correctly > inside nmi, right? They should, now, yes. There used to be issues with the whole "that re-enables NMI". Which reminds me. We never took your patches that use ljmp to handle the return-to-kernel mode. You did them for performance reasons, but I think the bigger deal was that it would have cleaned up that whole special case. Or did they have other problems? The ones to return to user space were admittedly more fun, but just a tad too crazy (and not _quite_ in the "crazy like a fox" camp ;) 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/