From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753932AbcAOQ4a (ORCPT ); Fri, 15 Jan 2016 11:56:30 -0500 Received: from www.linutronix.de ([62.245.132.108]:39009 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750810AbcAOQ43 (ORCPT ); Fri, 15 Jan 2016 11:56:29 -0500 Date: Fri, 15 Jan 2016 17:56:26 +0100 From: Sebastian Andrzej Siewior To: Grygorii Strashko Cc: Russell King , linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sekhar Nori Subject: Re: [4.4-rt2 PATCH] ARM: highmem: take into account FIX_KMAP_BEGIN in switch_kmaps() Message-ID: <20160115165626.GE3781@linutronix.de> References: <1452867647-1410-1-git-send-email-grygorii.strashko@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1452867647-1410-1-git-send-email-grygorii.strashko@ti.com> X-Key-Id: 2A8CF5D1 X-Key-Fingerprint: 6425 4695 FFF0 AA44 66CC 19E6 7B96 E816 2A8C F5D1 User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Grygorii Strashko | 2016-01-15 16:20:47 [+0200]: >Now the random crashes are observed on ARM TI am437x-idk-evm used with >-RT Kernel v4.4-rt2 and with Highmem enabled. > >The reason of issue is that, newly introduced switch_kmaps() does not >take into account FIX_KMAP_BEGIN, which was re-added by >commit a5f4c561b3b1 ("ARM: 8415/1: early fixmap support for earlycon") >(K4.3) for ARM and since that the value of FIX_KMAP_BEGIN >is not 0 any more. > >Hence update switch_kmaps() so it will take into FIX_KMAP_BEGIN while >calculating fixmap idx. This patch also introduces fixmap_idx() to >make code simpler and remove duplicated code. Thank you debugging and fixing this. I will fold this into the initial patch since it is a v4.1..v4.4 fallout. Regarding your "nobody else be me" question in the other mail: once I managed something ARM+highmem I I see this: |Welcome to Debian GNU/Linux stretch/sid! | |[ 11.738637] systemd[1]: Set hostname to . |[ 11.909949] ------------[ cut here ]------------ |[ 11.909958] kernel BUG at arch/arm/mm/highmem.c:90! So I did not get as far as a shell to start anything. >Signed-off-by: Grygorii Strashko >Signed-off-by: Russell King Sebastian