From patchwork Sat Nov 2 13:31:24 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mauro Carvalho Chehab X-Patchwork-Id: 3131111 Return-Path: X-Original-To: patchwork-linux-media@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id A5890BEEB2 for ; Sat, 2 Nov 2013 16:34:19 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id B9D7720375 for ; Sat, 2 Nov 2013 16:34:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A9EB42035C for ; Sat, 2 Nov 2013 16:34:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753922Ab3KBQeO (ORCPT ); Sat, 2 Nov 2013 12:34:14 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:60756 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753397Ab3KBQdm (ORCPT ); Sat, 2 Nov 2013 12:33:42 -0400 Received: from [177.143.133.66] (helo=smtp.w2.samsung.com) by bombadil.infradead.org with esmtpsa (Exim 4.80.1 #2 (Red Hat Linux)) id 1Vce8p-0008KF-RV; Sat, 02 Nov 2013 16:33:40 +0000 Received: from mchehab by smtp.w2.samsung.com with local (Exim 4.80.1) (envelope-from ) id 1VcbIh-00032z-7s; Sat, 02 Nov 2013 11:31:39 -0200 From: Mauro Carvalho Chehab Cc: Mauro Carvalho Chehab , Linux Media Mailing List , Mauro Carvalho Chehab , Jiri Kosina , Geert Uytterhoeven Subject: [PATCHv2 16/29] stv0367: Don't use dynamic static allocation Date: Sat, 2 Nov 2013 11:31:24 -0200 Message-Id: <1383399097-11615-17-git-send-email-m.chehab@samsung.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1383399097-11615-1-git-send-email-m.chehab@samsung.com> References: <1383399097-11615-1-git-send-email-m.chehab@samsung.com> To: unlisted-recipients:; (no To-header on input) Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Spam-Status: No, score=-7.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Dynamic static allocation is evil, as Kernel stack is too low, and compilation complains about it on some archs: drivers/media/dvb-frontends/stv0367.c:791:1: warning: 'stv0367_writeregs.constprop.4' uses dynamic stack allocation [enabled by default] Instead, let's enforce a limit for the buffer. Considering that I2C transfers are generally limited, and that devices used on USB has a max data length of 80, it seem safe to use 80 as the hard limit for all those devices. On most cases, the limit is a way lower than that, but 80 is small enough to not affect the Kernel stack, and it is a no brain limit, as using smaller ones would require to either carefully each driver or to take a look on each datasheet. Signed-off-by: Mauro Carvalho Chehab Cc: Jiri Kosina Cc: Geert Uytterhoeven --- drivers/media/dvb-frontends/stv0367.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/media/dvb-frontends/stv0367.c b/drivers/media/dvb-frontends/stv0367.c index 7b6dba3ce55e..28294b3be319 100644 --- a/drivers/media/dvb-frontends/stv0367.c +++ b/drivers/media/dvb-frontends/stv0367.c @@ -767,7 +767,7 @@ static struct st_register def0367cab[STV0367CAB_NBREGS] = { static int stv0367_writeregs(struct stv0367_state *state, u16 reg, u8 *data, int len) { - u8 buf[len + 2]; + u8 buf[80]; struct i2c_msg msg = { .addr = state->config->demod_address, .flags = 0, @@ -776,6 +776,14 @@ int stv0367_writeregs(struct stv0367_state *state, u16 reg, u8 *data, int len) }; int ret; + if (2 + len > sizeof(buf)) { + printk(KERN_WARNING + "%s: i2c wr reg=%04x: len=%d is too big!\n", + KBUILD_MODNAME, reg, len); + return -EREMOTEIO; + } + + buf[0] = MSB(reg); buf[1] = LSB(reg); memcpy(buf + 2, data, len);