From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754451AbcISJZq (ORCPT ); Mon, 19 Sep 2016 05:25:46 -0400 Received: from mail-wm0-f44.google.com ([74.125.82.44]:37068 "EHLO mail-wm0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751129AbcISJZe (ORCPT ); Mon, 19 Sep 2016 05:25:34 -0400 Date: Mon, 19 Sep 2016 10:25:31 +0100 From: Matt Fleming To: Waiman Long Cc: Linus Torvalds , "Theodore Ts'o" , Arnd Bergmann , Greg Kroah-Hartman , Linux Kernel Mailing List , Scott J Norton , Douglas Hatch , Borislav Petkov Subject: Re: [PATCH] random: Fix kernel panic due to system_wq use before init Message-ID: <20160919092531.GA2892@codeblueprint.co.uk> References: <1473879781-23819-1-git-send-email-Waiman.Long@hpe.com> <57D9A1A9.8050506@hpe.com> <57DF56D4.50304@hpe.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <57DF56D4.50304@hpe.com> User-Agent: Mutt/1.5.24+41 (02bc14ed1569) (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 18 Sep, at 11:09:08PM, Waiman Long wrote: > > I have finally finished bisecting the problem. I was wrong in saying that > the 4.7.3 kernel had no problem. It did have. There were some slight > differences between the 4.8 and 4.7 kernel config files that I used. After > some further testing, it was found that the bootup problem only happened > when the following kernel config option was defined: > > CONFIG_EFI_MIXED=y > > Bisecting reviewed that the following 4.6 patch was the first patch that had > this problem: > > c9f2a9a65e4855b74d92cdad688f6ee4a1a323ff > [PATCH] x86/efi: Hoist page table switching code into efi_call_virt() > > I did testing on my test system with three different partition sizes: > 1) 16-socket Broadwell-EX with 12TB memory > 2) 8-socket Broadwell-EX with 6TB memory > 3) 4-socket Broadwell-EX with 3TB memory > > Only the 16-socket and 8-socket configurations had this problem. I am not > sure if over 4TB of main memory is a factor or not. Yes, I think it's a safe bet that the amount of main memory is a major factor here. Thanks for the report. The only real difference when CONFIG_EFI_MIXED is enabled for 64-bit kernel and 64-bit firmware is that main memory will be mapped into the EFI page tables at its physical addresses. I'll go stare at the code and get back to you.