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 C1C62CA9EA0 for ; Tue, 22 Oct 2019 09:17:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9EB062064B for ; Tue, 22 Oct 2019 09:17:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388155AbfJVJRN convert rfc822-to-8bit (ORCPT ); Tue, 22 Oct 2019 05:17:13 -0400 Received: from relay12.mail.gandi.net ([217.70.178.232]:50863 "EHLO relay12.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388006AbfJVJRN (ORCPT ); Tue, 22 Oct 2019 05:17:13 -0400 Received: from xps13 (lfbn-1-17395-211.w86-250.abo.wanadoo.fr [86.250.200.211]) (Authenticated sender: miquel.raynal@bootlin.com) by relay12.mail.gandi.net (Postfix) with ESMTPSA id A20A320001B; Tue, 22 Oct 2019 09:17:08 +0000 (UTC) Date: Tue, 22 Oct 2019 11:17:07 +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: <20191022111707.4b117b99@xps13> In-Reply-To: <20191022082643.GO25745@shell.armlinux.org.uk> References: <20191018143643.29676-1-miquel.raynal@bootlin.com> <20191022082643.GO25745@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=UTF-8 Content-Transfer-Encoding: 8BIT 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 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. Here is the full trace when writing 1001 bytes: # dd if=/dev/urandom bs=1001 count=1 of=/dev/mtd6 Unhandled fault: external abort on non-linefetch (0x808) at 0xc90703e8 pgd = c7be8000 [c90703e8] *pgd=f8000452(bad) Internal error: : 808 [#1] ARM Modules linked in: CPU: 0 PID: 660 Comm: dd Not tainted 4.14.0-00045-gf5d08192704f-dirty #6 Hardware name: ST SPEAr600 (Flattened Device Tree) task: c7a05080 task.stack: c7bd2000 PC is at memcpy+0xcc/0x330 LR is at 0x13f0ec28 pc : [] lr : [<13f0ec28>] psr: 80000013 sp : c7bd3e44 ip : 00000018 fp : 000003e9 r10: 00000000 r9 : c7a9959c r8 : c7bd3eac r7 : c7a99590 r6 : c7afb438 r5 : 00000300 r4 : 5171436c r3 : 00000058 r2 : 80000000 r1 : c7be4be9 r0 : c90703e8 Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none Control: 0005317f Table: 07be8000 DAC: 00000051 Process dd (pid: 660, stack limit = 0xc7bd2190) Stack: (0xc7bd3e44 to 0xc7bd4000) 3e40: c9070300 000000e9 c0290d14 c9070300 c7be4b00 0001046f c9070000 3e60: c7afb418 00000000 c7bd3e98 000003e9 c7bd3f88 000003e9 00000000 000c0008 3e80: 00000051 c7bd2000 c7be4800 c028e57c 000003e9 c7bd3eac c7be4800 00000000 3ea0: c7bf73c0 c7addc00 000003e9 00000300 00000000 00000000 00000000 00000000 3ec0: 00000000 00000000 00000000 00000000 00000000 000003e9 c028e4bc c7962a80 3ee0: c7bd3f88 00000000 c7bd2000 00000000 000bf990 c00bdb0c 000bf990 c00bd878 3f00: 00000000 00000000 00000000 c7bd3f10 c7a688c0 c009eedc c7becb58 000c0000 3f20: 00000003 c7962460 c7962484 00000000 00000000 c045c2f8 00000003 c00d9e58 3f40: 000003e9 000c0008 c7962a80 c7bd3f88 00000000 c7bd2000 00000000 c00bddb4 3f60: 000bf990 c00bda6c 00000000 c7962a80 c7962a80 000c0008 000003e9 c000a804 3f80: c7bd2000 c00bdfa4 00000000 00000000 00000000 000bfd94 00000001 000c0008 3fa0: 00000004 c000a640 000bfd94 00000001 00000001 000c0008 000003e9 be8e8f53 3fc0: 000bfd94 00000001 000c0008 00000004 000c0008 000c0008 000003e9 000bf990 3fe0: 00000000 be8e8ba4 0000ea3c b6eba7ec 60000010 00000001 00000000 00000000 [] (memcpy) from [] (spear_mtd_write+0x240/0x294) [] (spear_mtd_write) from [] (mtdchar_write+0xc0/0x230) [] (mtdchar_write) from [] (__vfs_write+0x1c/0x128) [] (__vfs_write) from [] (vfs_write+0xa0/0x168) [] (vfs_write) from [] (SyS_write+0x3c/0x90) [] (SyS_write) from [] (ret_fast_syscall+0x0/0x44) Code: e1b02f82 14d13001 24d14001 24d1c001 (14c03001) ---[ end trace f9a736cc2841cf14 ]--- Segmentation fault Thanks, Miquèl