Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752189AbaKZFwj (ORCPT ); Wed, 26 Nov 2014 00:52:39 -0500 Received: from mail-qg0-f47.google.com ([209.85.192.47]:59172 "EHLO mail-qg0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751091AbaKZFwh (ORCPT ); Wed, 26 Nov 2014 00:52:37 -0500 MIME-Version: 1.0 In-Reply-To: <54756424.6020409@suse.com> References: <20141114213124.GB3344@redhat.com> <20141115213405.GA31971@redhat.com> <20141116014006.GA5016@redhat.com> <20141126002501.GA11752@redhat.com> <5475596A.9010301@suse.com> <54756424.6020409@suse.com> Date: Tue, 25 Nov 2014 21:52:37 -0800 X-Google-Sender-Auth: 5ebAo9aerG0xmpupqYZYtpghWj4 Message-ID: Subject: Re: frequent lockups in 3.18rc4 From: Linus Torvalds To: Juergen Gross Cc: "the arch/x86 maintainers" , Kernel Mailing List , Dave Jones 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 Tue, Nov 25, 2014 at 9:24 PM, Juergen Gross wrote: > > Working on it. Triggering it via sysrq(l) isn't working: machine hung > up. I'll try a dump, but this might take some time due to the machine > size... Actually, in that patch that did this: - pgd = pgd_offset(current->active_mm, address); + pgd = (pgd_t *)__va(read_cr3()) + pgd_index(address); make the code do: pgd = (pgd_t *)__va(read_cr3()) + pgd_index(address); WARN_ON(pdg != pgd_offset(current->active_mm, address)); and now you should get a nice backtrace for exactly when it happens, but it's on a working kernel, so nothing will lock up. Hmm? And leave it running for a while, and see if the trace is always the same, or if there are variations on it... Thanks, 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/