From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8E38BCA9EA0 for ; Tue, 22 Oct 2019 09:47:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 609882089E for ; Tue, 22 Oct 2019 09:47:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731437AbfJVJrm (ORCPT ); Tue, 22 Oct 2019 05:47:42 -0400 Received: from relay10.mail.gandi.net ([217.70.178.230]:53627 "EHLO relay10.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730619AbfJVJrl (ORCPT ); Tue, 22 Oct 2019 05:47:41 -0400 Received: from xps13 (lfbn-1-17395-211.w86-250.abo.wanadoo.fr [86.250.200.211]) (Authenticated sender: miquel.raynal@bootlin.com) by relay10.mail.gandi.net (Postfix) with ESMTPSA id 295AD24000B; Tue, 22 Oct 2019 09:47:36 +0000 (UTC) Date: Tue, 22 Oct 2019 11:47:35 +0200 From: Miquel Raynal To: Russell King - ARM Linux admin Cc: Richard Weinberger , David Woodhouse , Brian Norris , Marek Vasut , Tudor Ambarus , Vignesh Raghavendra , stable@vger.kernel.org, Boris Brezillon , linux-mtd@lists.infradead.org, Thomas Petazzoni , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] mtd: spear_smi: Fix nonalignment not handled in memcpy_toio Message-ID: <20191022114735.0321864e@xps13> In-Reply-To: <20191022092619.GQ25745@shell.armlinux.org.uk> References: <20191018143643.29676-1-miquel.raynal@bootlin.com> <20191022082643.GO25745@shell.armlinux.org.uk> <20191022111707.4b117b99@xps13> <20191022092619.GQ25745@shell.armlinux.org.uk> Organization: Bootlin X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Hi Russell, Russell King - ARM Linux admin wrote on Tue, 22 Oct 2019 10:26:19 +0100: > On Tue, Oct 22, 2019 at 11:17:07AM +0200, Miquel Raynal wrote: > > Hi Russell, > > > > Russell King - ARM Linux admin wrote on Tue, 22 > > Oct 2019 09:26:43 +0100: > > > > > On Fri, Oct 18, 2019 at 04:36:43PM +0200, Miquel Raynal wrote: > > > > Any write with either dd or flashcp to a device driven by the > > > > spear_smi.c driver will pass through the spear_smi_cpy_toio() > > > > function. This function will get called for chunks of up to 256 bytes. > > > > If the amount of data is smaller, we may have a problem if the data > > > > length is not 4-byte aligned. In this situation, the kernel panics > > > > during the memcpy: > > > > > > > > # dd if=/dev/urandom bs=1001 count=1 of=/dev/mtd6 > > > > spear_smi_cpy_toio [620] dest c9070000, src c7be8800, len 256 > > > > spear_smi_cpy_toio [620] dest c9070100, src c7be8900, len 256 > > > > spear_smi_cpy_toio [620] dest c9070200, src c7be8a00, len 256 > > > > spear_smi_cpy_toio [620] dest c9070300, src c7be8b00, len 233 > > > > Unhandled fault: external abort on non-linefetch (0x808) at 0xc90703e8 > > > > [...] > > > > PC is at memcpy+0xcc/0x330 > > > > > > I need the full oops if you want me to comment on this. > > > > FYI, I ran the dd command within a for loop, incrementing the block size > > (bs) by one byte, if failed with bs=6. > > > > Disabling WB_MODE (burst mode) does not change anything. > > > > Adding a wmb() right after the memcpy_toio() prevents the fault. > > Thanks. Can you check what the result of the write buffer test earlier > in the kernel boot is? > > CPU: Testing write buffer coherency: ... > > ? CPU: Testing write buffer coherency: ok