From patchwork Fri Feb 16 16:31:44 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 773872 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EBF52219ED; Fri, 16 Feb 2024 16:32:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708101128; cv=none; b=OeGM/SQDzTyae3VuXQjTkHMqwCz30kHxlLKn4bPRXQswTotgVT0QKXrixPbbt9Uy8o1MHBS9PLvIIIKpSDozkBuPca6GKi/ZloUTs9vpDq2e5qqs7488dGT+z+gasGCc+9MnUvkTs2Q4fw3xeqM/5uUVVxYwGKSYVZe5NN/1VDM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708101128; c=relaxed/simple; bh=JGR9oWuh9+Gj4ak7aoBRm7nN1ezVNuRLhjn7Tq1Dsog=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=fOso0/9urkWPXj6CbF09JXVnJTkZRE+SDOqqQprcYNvDy2ZITjmOdOAIRVR+WRHC/3zuZ+NKv/WhfANGrQle5BRffXXdSaiQ7GV5KImjnTJIyRRu5VLeoeX9WKfEInRVghOx8i26k/zIpUF3+4Z2EdwPRvDS+KjDYrEPq/3SNFU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ba9T0zMH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ba9T0zMH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CCBC8C43390; Fri, 16 Feb 2024 16:32:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1708101127; bh=JGR9oWuh9+Gj4ak7aoBRm7nN1ezVNuRLhjn7Tq1Dsog=; h=From:To:Cc:Subject:Date:From; b=Ba9T0zMHZyf/Ke4gnCc2keIIDMRzmRuPhteX/as0JvsiQ2E3w6CyWZB5GXO6EOOXl ucXIIJiRkzT2EjoREmF0CVtbFqRuO1tq6H1hwyV+L8t1gP1HNJH1+LEFC7cBRskE+l 2FRK/nqeRrzX0tnK9giDxPJdiRS2pULsRPuix+xkfs/y/sWmfPAU3E5E9iq2WGQeAS hhWBqo3mGxn44UfaWRAJ3Fe7HibrSYJ+0FMJdy7G/59XRD960WwNBU/yDqZJkkVBT1 542yYzoTa7b4wTPlf7JqZhkDuSgRKIh+YyM10hckMc9K91iF+6w0G23eW1wigsO2nP NjUY67zUcgAHg== From: Arnd Bergmann To: Mauro Carvalho Chehab Cc: Hans Verkuil , Laurent Pinchart , Arnd Bergmann , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Mark Brown , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev Subject: [PATCH] media: dvb-frontends: avoid stack overflow warnings with clang Date: Fri, 16 Feb 2024 17:31:44 +0100 Message-Id: <20240216163201.1901744-1-arnd@kernel.org> X-Mailer: git-send-email 2.39.2 Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Arnd Bergmann A previous patch worked around a KASAN issue in stv0367, now a similar problem showed up with clang: drivers/media/dvb-frontends/stv0367.c:1222:12: error: stack frame size (3624) exceeds limit (2048) in 'stv0367ter_set_frontend' [-Werror,-Wframe-larger-than] 1214 | static int stv0367ter_set_frontend(struct dvb_frontend *fe) Rework the stv0367_writereg() function to be simpler and mark both register access functions as noinline_for_stack so the temporary i2c_msg structures do not get duplicated on the stack when KASAN_STACK is enabled. Fixes: 3cd890dbe2a4 ("media: dvb-frontends: fix i2c access helpers for KASAN") Signed-off-by: Arnd Bergmann --- drivers/media/dvb-frontends/stv0367.c | 34 +++++++-------------------- 1 file changed, 8 insertions(+), 26 deletions(-) diff --git a/drivers/media/dvb-frontends/stv0367.c b/drivers/media/dvb-frontends/stv0367.c index 48326434488c..72540ef4e5f8 100644 --- a/drivers/media/dvb-frontends/stv0367.c +++ b/drivers/media/dvb-frontends/stv0367.c @@ -118,50 +118,32 @@ static const s32 stv0367cab_RF_LookUp2[RF_LOOKUP_TABLE2_SIZE][RF_LOOKUP_TABLE2_S } }; -static -int stv0367_writeregs(struct stv0367_state *state, u16 reg, u8 *data, int len) +static noinline_for_stack +int stv0367_writereg(struct stv0367_state *state, u16 reg, u8 data) { - u8 buf[MAX_XFER_SIZE]; + u8 buf[3] = { MSB(reg), LSB(reg), data }; struct i2c_msg msg = { .addr = state->config->demod_address, .flags = 0, .buf = buf, - .len = len + 2 + .len = 3, }; 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 -EINVAL; - } - - - buf[0] = MSB(reg); - buf[1] = LSB(reg); - memcpy(buf + 2, data, len); - if (i2cdebug) printk(KERN_DEBUG "%s: [%02x] %02x: %02x\n", __func__, - state->config->demod_address, reg, buf[2]); + state->config->demod_address, reg, data); ret = i2c_transfer(state->i2c, &msg, 1); if (ret != 1) printk(KERN_ERR "%s: i2c write error! ([%02x] %02x: %02x)\n", - __func__, state->config->demod_address, reg, buf[2]); + __func__, state->config->demod_address, reg, data); return (ret != 1) ? -EREMOTEIO : 0; } -static int stv0367_writereg(struct stv0367_state *state, u16 reg, u8 data) -{ - u8 tmp = data; /* see gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 */ - - return stv0367_writeregs(state, reg, &tmp, 1); -} - -static u8 stv0367_readreg(struct stv0367_state *state, u16 reg) +static noinline_for_stack +u8 stv0367_readreg(struct stv0367_state *state, u16 reg) { u8 b0[] = { 0, 0 }; u8 b1[] = { 0 };