From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:40188 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935978AbeBUNFJ (ORCPT ); Wed, 21 Feb 2018 08:05:09 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Arnd Bergmann , Mauro Carvalho Chehab Subject: [PATCH 4.14 162/167] media: r820t: fix r820t_write_reg for KASAN Date: Wed, 21 Feb 2018 13:49:33 +0100 Message-Id: <20180221124533.710405666@linuxfoundation.org> In-Reply-To: <20180221124524.639039577@linuxfoundation.org> References: <20180221124524.639039577@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann commit 16c3ada89cff9a8c2a0eea34ffa1aa20af3f6008 upstream. With CONFIG_KASAN, we get an overly long stack frame due to inlining the register access functions: drivers/media/tuners/r820t.c: In function 'generic_set_freq.isra.7': drivers/media/tuners/r820t.c:1334:1: error: the frame size of 2880 bytes is larger than 2048 bytes [-Werror=frame-larger-than=] This is caused by a gcc bug that has now been fixed in gcc-8. To work around the problem, we can pass the register data through a local variable that older gcc versions can optimize out as well. Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 Signed-off-by: Arnd Bergmann Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Greg Kroah-Hartman --- drivers/media/tuners/r820t.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) --- a/drivers/media/tuners/r820t.c +++ b/drivers/media/tuners/r820t.c @@ -396,9 +396,11 @@ static int r820t_write(struct r820t_priv return 0; } -static int r820t_write_reg(struct r820t_priv *priv, u8 reg, u8 val) +static inline int r820t_write_reg(struct r820t_priv *priv, u8 reg, u8 val) { - return r820t_write(priv, reg, &val, 1); + u8 tmp = val; /* work around GCC PR81715 with asan-stack=1 */ + + return r820t_write(priv, reg, &tmp, 1); } static int r820t_read_cache_reg(struct r820t_priv *priv, int reg) @@ -411,17 +413,18 @@ static int r820t_read_cache_reg(struct r return -EINVAL; } -static int r820t_write_reg_mask(struct r820t_priv *priv, u8 reg, u8 val, +static inline int r820t_write_reg_mask(struct r820t_priv *priv, u8 reg, u8 val, u8 bit_mask) { + u8 tmp = val; int rc = r820t_read_cache_reg(priv, reg); if (rc < 0) return rc; - val = (rc & ~bit_mask) | (val & bit_mask); + tmp = (rc & ~bit_mask) | (tmp & bit_mask); - return r820t_write(priv, reg, &val, 1); + return r820t_write(priv, reg, &tmp, 1); } static int r820t_read(struct r820t_priv *priv, u8 reg, u8 *val, int len)