From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752477AbeBBPJE (ORCPT ); Fri, 2 Feb 2018 10:09:04 -0500 Received: from mail5.windriver.com ([192.103.53.11]:57912 "EHLO mail5.wrs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752450AbeBBPI5 (ORCPT ); Fri, 2 Feb 2018 10:08:57 -0500 Subject: Re: [PATCH] kdb: use memmove instead of overlapping memcpy To: Arnd Bergmann , Daniel Thompson CC: Nicolas Pitre , Andi Kleen , , References: <20180202145952.285505-1-arnd@arndb.de> From: Jason Wessel Message-ID: <0304cb01-ed28-d16f-9384-1443db682b5c@windriver.com> Date: Fri, 2 Feb 2018 09:08:40 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <20180202145952.285505-1-arnd@arndb.de> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/02/2018 08:59 AM, Arnd Bergmann wrote: > gcc discovered that the memcpy() arguments in kdbnearsym() overlap, so > we should really use memmove(), which is defined to handle that correctly: > > In function 'memcpy', > inlined from 'kdbnearsym' at /git/arm-soc/kernel/debug/kdb/kdb_support.c:132:4: > /git/arm-soc/include/linux/string.h:353:9: error: '__builtin_memcpy' accessing 792 bytes at offsets 0 and 8 overlaps 784 bytes at offset 8 [-Werror=restrict] > return __builtin_memcpy(p, q, size); > > Signed-off-by: Arnd Bergmann > --- > kernel/debug/kdb/kdb_support.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/kernel/debug/kdb/kdb_support.c b/kernel/debug/kdb/kdb_support.c > index 5d8ef3a07ecd..1ad4370ccbf0 100644 > --- a/kernel/debug/kdb/kdb_support.c > +++ b/kernel/debug/kdb/kdb_support.c > @@ -129,13 +129,13 @@ int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab) > } > if (i >= ARRAY_SIZE(kdb_name_table)) { > debug_kfree(kdb_name_table[0]); > - memcpy(kdb_name_table, kdb_name_table+1, > + memmove(kdb_name_table, kdb_name_table+1, > sizeof(kdb_name_table[0]) * > (ARRAY_SIZE(kdb_name_table)-1)); > } else { > debug_kfree(knt1); > knt1 = kdb_name_table[i]; > - memcpy(kdb_name_table+i, kdb_name_table+i+1, > + memmove(kdb_name_table+i, kdb_name_table+i+1, > sizeof(kdb_name_table[0]) * > (ARRAY_SIZE(kdb_name_table)-i-1)); > } > That is good by me. Many thanks! Added to queue. Reviewed-by: Jason Wessel Jason.