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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 A338AC6778A for ; Sat, 7 Jul 2018 10:01:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4FBAE21A08 for ; Sat, 7 Jul 2018 10:01:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4FBAE21A08 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932474AbeGGKBk (ORCPT ); Sat, 7 Jul 2018 06:01:40 -0400 Received: from mail.bootlin.com ([62.4.15.54]:51674 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752890AbeGGKBj (ORCPT ); Sat, 7 Jul 2018 06:01:39 -0400 Received: by mail.bootlin.com (Postfix, from userid 110) id B11CA207BD; Sat, 7 Jul 2018 12:01:36 +0200 (CEST) Received: from bbrezillon (91-160-177-164.subs.proxad.net [91.160.177.164]) by mail.bootlin.com (Postfix) with ESMTPSA id 72DF920741; Sat, 7 Jul 2018 12:01:36 +0200 (CEST) Date: Sat, 7 Jul 2018 12:01:37 +0200 From: Boris Brezillon To: Geert Uytterhoeven Cc: David Woodhouse , Brian Norris , Marek Vasut , Richard Weinberger , Masahiro Yamada , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mtd: Use kasprintf() instead of fixed buffer formatting Message-ID: <20180707120137.00220db0@bbrezillon> In-Reply-To: <20180628082011.19553-1-geert+renesas@glider.be> References: <20180628082011.19553-1-geert+renesas@glider.be> X-Mailer: Claws Mail 3.15.0-dirty (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 28 Jun 2018 10:20:11 +0200 Geert Uytterhoeven wrote: > Using "%4.4X" in the calculation of the buffer size is misleading, as > the format string literal has no relation to the actual size needed. > Hence this is fragile w.r.t. future modification. > > As this is not a hot path, fix this by replacing the formatting in a > fixed buffer by kasprintf(). > > Signed-off-by: Geert Uytterhoeven Applied. Thanks, Boris > --- > Compile-tested only. > > Interestingly, this decreases code size (by 16 resp. 24 bytes on arm32 > resp. arm64). > --- > drivers/mtd/chips/gen_probe.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/mtd/chips/gen_probe.c b/drivers/mtd/chips/gen_probe.c > index 879bebf9d8b12038..837b04ab96a9c526 100644 > --- a/drivers/mtd/chips/gen_probe.c > +++ b/drivers/mtd/chips/gen_probe.c > @@ -202,16 +202,19 @@ static inline struct mtd_info *cfi_cmdset_unknown(struct map_info *map, > struct cfi_private *cfi = map->fldrv_priv; > __u16 type = primary?cfi->cfiq->P_ID:cfi->cfiq->A_ID; > #ifdef CONFIG_MODULES > - char probename[sizeof("cfi_cmdset_%4.4X")]; > cfi_cmdset_fn_t *probe_function; > + char *probename; > > - sprintf(probename, "cfi_cmdset_%4.4X", type); > + probename = kasprintf(GFP_KERNEL, "cfi_cmdset_%4.4X", type); > + if (!probename) > + return NULL; > > probe_function = __symbol_get(probename); > if (!probe_function) { > request_module("cfi_cmdset_%4.4X", type); > probe_function = __symbol_get(probename); > } > + kfree(probename); > > if (probe_function) { > struct mtd_info *mtd;