From: Antti Palosaari <crope@iki.fi>
To: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: Linux Media Mailing List <linux-media@vger.kernel.org>,
Mauro Carvalho Chehab <mchehab@infradead.org>
Subject: Re: [PATCHv2 19/29] tuners: Don't use dynamic static allocation
Date: Sat, 02 Nov 2013 19:12:20 +0200 [thread overview]
Message-ID: <52753274.4020205@iki.fi> (raw)
In-Reply-To: <1383399097-11615-20-git-send-email-m.chehab@samsung.com>
Acked-by: Antti Palosaari <crope@iki.fi>
Reviewed-by: Antti Palosaari <crope@iki.fi>
Antti
On 02.11.2013 15:31, Mauro Carvalho Chehab wrote:
> Dynamic static allocation is evil, as Kernel stack is too low, and
> compilation complains about it on some archs:
>
> drivers/media/tuners/e4000.c:50:1: warning: 'e4000_wr_regs' uses dynamic stack allocation [enabled by default]
> drivers/media/tuners/e4000.c:83:1: warning: 'e4000_rd_regs' uses dynamic stack allocation [enabled by default]
> drivers/media/tuners/fc2580.c:66:1: warning: 'fc2580_wr_regs.constprop.1' uses dynamic stack allocation [enabled by default]
> drivers/media/tuners/fc2580.c:98:1: warning: 'fc2580_rd_regs.constprop.0' uses dynamic stack allocation [enabled by default]
> drivers/media/tuners/tda18212.c:57:1: warning: 'tda18212_wr_regs' uses dynamic stack allocation [enabled by default]
> drivers/media/tuners/tda18212.c:90:1: warning: 'tda18212_rd_regs.constprop.0' uses dynamic stack allocation [enabled by default]
> drivers/media/tuners/tda18218.c:60:1: warning: 'tda18218_wr_regs' uses dynamic stack allocation [enabled by default]
> drivers/media/tuners/tda18218.c:92:1: warning: 'tda18218_rd_regs.constprop.0' 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 <m.chehab@samsung.com>
> Cc: Antti Palosaari <crope@iki.fi>
> ---
> drivers/media/tuners/e4000.c | 18 ++++++++++++++++--
> drivers/media/tuners/fc2580.c | 18 ++++++++++++++++--
> drivers/media/tuners/tda18212.c | 18 ++++++++++++++++--
> drivers/media/tuners/tda18218.c | 18 ++++++++++++++++--
> 4 files changed, 64 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/media/tuners/e4000.c b/drivers/media/tuners/e4000.c
> index ad9309da4a91..235e90251609 100644
> --- a/drivers/media/tuners/e4000.c
> +++ b/drivers/media/tuners/e4000.c
> @@ -24,7 +24,7 @@
> static int e4000_wr_regs(struct e4000_priv *priv, u8 reg, u8 *val, int len)
> {
> int ret;
> - u8 buf[1 + len];
> + u8 buf[80];
> struct i2c_msg msg[1] = {
> {
> .addr = priv->cfg->i2c_addr,
> @@ -34,6 +34,13 @@ static int e4000_wr_regs(struct e4000_priv *priv, u8 reg, u8 *val, int len)
> }
> };
>
> + if (1 + len > sizeof(buf)) {
> + dev_warn(&priv->i2c->dev,
> + "%s: i2c wr reg=%04x: len=%d is too big!\n",
> + KBUILD_MODNAME, reg, len);
> + return -EREMOTEIO;
> + }
> +
> buf[0] = reg;
> memcpy(&buf[1], val, len);
>
> @@ -53,7 +60,7 @@ static int e4000_wr_regs(struct e4000_priv *priv, u8 reg, u8 *val, int len)
> static int e4000_rd_regs(struct e4000_priv *priv, u8 reg, u8 *val, int len)
> {
> int ret;
> - u8 buf[len];
> + u8 buf[80];
> struct i2c_msg msg[2] = {
> {
> .addr = priv->cfg->i2c_addr,
> @@ -68,6 +75,13 @@ static int e4000_rd_regs(struct e4000_priv *priv, u8 reg, u8 *val, int len)
> }
> };
>
> + if (len > sizeof(buf)) {
> + dev_warn(&priv->i2c->dev,
> + "%s: i2c rd reg=%04x: len=%d is too big!\n",
> + KBUILD_MODNAME, reg, len);
> + return -EREMOTEIO;
> + }
> +
> ret = i2c_transfer(priv->i2c, msg, 2);
> if (ret == 2) {
> memcpy(val, buf, len);
> diff --git a/drivers/media/tuners/fc2580.c b/drivers/media/tuners/fc2580.c
> index 81f38aae9c66..e27bf5be311d 100644
> --- a/drivers/media/tuners/fc2580.c
> +++ b/drivers/media/tuners/fc2580.c
> @@ -41,7 +41,7 @@
> static int fc2580_wr_regs(struct fc2580_priv *priv, u8 reg, u8 *val, int len)
> {
> int ret;
> - u8 buf[1 + len];
> + u8 buf[80];
> struct i2c_msg msg[1] = {
> {
> .addr = priv->cfg->i2c_addr,
> @@ -51,6 +51,13 @@ static int fc2580_wr_regs(struct fc2580_priv *priv, u8 reg, u8 *val, int len)
> }
> };
>
> + if (1 + len > sizeof(buf)) {
> + dev_warn(&priv->i2c->dev,
> + "%s: i2c wr reg=%04x: len=%d is too big!\n",
> + KBUILD_MODNAME, reg, len);
> + return -EREMOTEIO;
> + }
> +
> buf[0] = reg;
> memcpy(&buf[1], val, len);
>
> @@ -69,7 +76,7 @@ static int fc2580_wr_regs(struct fc2580_priv *priv, u8 reg, u8 *val, int len)
> static int fc2580_rd_regs(struct fc2580_priv *priv, u8 reg, u8 *val, int len)
> {
> int ret;
> - u8 buf[len];
> + u8 buf[80];
> struct i2c_msg msg[2] = {
> {
> .addr = priv->cfg->i2c_addr,
> @@ -84,6 +91,13 @@ static int fc2580_rd_regs(struct fc2580_priv *priv, u8 reg, u8 *val, int len)
> }
> };
>
> + if (len > sizeof(buf)) {
> + dev_warn(&priv->i2c->dev,
> + "%s: i2c rd reg=%04x: len=%d is too big!\n",
> + KBUILD_MODNAME, reg, len);
> + return -EREMOTEIO;
> + }
> +
> ret = i2c_transfer(priv->i2c, msg, 2);
> if (ret == 2) {
> memcpy(val, buf, len);
> diff --git a/drivers/media/tuners/tda18212.c b/drivers/media/tuners/tda18212.c
> index e4a84ee231cf..765b9f9d4bc6 100644
> --- a/drivers/media/tuners/tda18212.c
> +++ b/drivers/media/tuners/tda18212.c
> @@ -32,7 +32,7 @@ static int tda18212_wr_regs(struct tda18212_priv *priv, u8 reg, u8 *val,
> int len)
> {
> int ret;
> - u8 buf[len+1];
> + u8 buf[80];
> struct i2c_msg msg[1] = {
> {
> .addr = priv->cfg->i2c_address,
> @@ -42,6 +42,13 @@ static int tda18212_wr_regs(struct tda18212_priv *priv, u8 reg, u8 *val,
> }
> };
>
> + if (1 + len > sizeof(buf)) {
> + dev_warn(&priv->i2c->dev,
> + "%s: i2c wr reg=%04x: len=%d is too big!\n",
> + KBUILD_MODNAME, reg, len);
> + return -EREMOTEIO;
> + }
> +
> buf[0] = reg;
> memcpy(&buf[1], val, len);
>
> @@ -61,7 +68,7 @@ static int tda18212_rd_regs(struct tda18212_priv *priv, u8 reg, u8 *val,
> int len)
> {
> int ret;
> - u8 buf[len];
> + u8 buf[80];
> struct i2c_msg msg[2] = {
> {
> .addr = priv->cfg->i2c_address,
> @@ -76,6 +83,13 @@ static int tda18212_rd_regs(struct tda18212_priv *priv, u8 reg, u8 *val,
> }
> };
>
> + if (len > sizeof(buf)) {
> + dev_warn(&priv->i2c->dev,
> + "%s: i2c rd reg=%04x: len=%d is too big!\n",
> + KBUILD_MODNAME, reg, len);
> + return -EREMOTEIO;
> + }
> +
> ret = i2c_transfer(priv->i2c, msg, 2);
> if (ret == 2) {
> memcpy(val, buf, len);
> diff --git a/drivers/media/tuners/tda18218.c b/drivers/media/tuners/tda18218.c
> index 2d31aeb6b088..e4e662c2e6ef 100644
> --- a/drivers/media/tuners/tda18218.c
> +++ b/drivers/media/tuners/tda18218.c
> @@ -24,7 +24,7 @@
> static int tda18218_wr_regs(struct tda18218_priv *priv, u8 reg, u8 *val, u8 len)
> {
> int ret = 0, len2, remaining;
> - u8 buf[1 + len];
> + u8 buf[80];
> struct i2c_msg msg[1] = {
> {
> .addr = priv->cfg->i2c_address,
> @@ -33,6 +33,13 @@ static int tda18218_wr_regs(struct tda18218_priv *priv, u8 reg, u8 *val, u8 len)
> }
> };
>
> + if (1 + len > sizeof(buf)) {
> + dev_warn(&priv->i2c->dev,
> + "%s: i2c wr reg=%04x: len=%d is too big!\n",
> + KBUILD_MODNAME, reg, len);
> + return -EREMOTEIO;
> + }
> +
> for (remaining = len; remaining > 0;
> remaining -= (priv->cfg->i2c_wr_max - 1)) {
> len2 = remaining;
> @@ -63,7 +70,7 @@ static int tda18218_wr_regs(struct tda18218_priv *priv, u8 reg, u8 *val, u8 len)
> static int tda18218_rd_regs(struct tda18218_priv *priv, u8 reg, u8 *val, u8 len)
> {
> int ret;
> - u8 buf[reg+len]; /* we must start read always from reg 0x00 */
> + u8 buf[80]; /* we must start read always from reg 0x00 */
> struct i2c_msg msg[2] = {
> {
> .addr = priv->cfg->i2c_address,
> @@ -78,6 +85,13 @@ static int tda18218_rd_regs(struct tda18218_priv *priv, u8 reg, u8 *val, u8 len)
> }
> };
>
> + if (reg + len > sizeof(buf)) {
> + dev_warn(&priv->i2c->dev,
> + "%s: i2c wr reg=%04x: len=%d is too big!\n",
> + KBUILD_MODNAME, reg, len);
> + return -EREMOTEIO;
> + }
> +
> ret = i2c_transfer(priv->i2c, msg, 2);
> if (ret == 2) {
> memcpy(val, &buf[reg], len);
>
--
http://palosaari.fi/
next prev parent reply other threads:[~2013-11-02 17:12 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-02 13:31 [PATCHv2 00/29] Fix errors/warnings with allmodconfig/allyesconfig on non-x86 archs Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 01/29] tda9887: remove an warning when compiling for alpha Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 02/29] radio-shark: remove a warning when CONFIG_PM is not defined Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 03/29] zoran: don't build it on alpha Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 04/29] cx18: struct i2c_client is too big for stack Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 05/29] tef6862: fix warning on avr32 arch Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 06/29] iguanair: shut up a gcc " Mauro Carvalho Chehab
2013-11-03 22:10 ` Sean Young
2013-11-03 22:13 ` [PATCH] [media] iguanair: simplify calculation of carrier delay cycles Sean Young
2013-11-02 13:31 ` [PATCHv2 07/29] platform drivers: Fix build on cris and frv archs Mauro Carvalho Chehab
2013-11-04 4:03 ` Ben Hutchings
2013-11-04 11:28 ` Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 08/29] cx18: disable compilation on frv arch Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 09/29] radio-si470x-i2c: fix a warning on ia64 Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 10/29] rc: Fir warnings on m68k arch Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 11/29] uvc/lirc_serial: Fix some warnings on parisc arch Mauro Carvalho Chehab
2013-11-04 14:22 ` Laurent Pinchart
2013-11-04 14:43 ` Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 12/29] s5h1420: Don't use dynamic static allocation Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 13/29] dvb-frontends: " Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 14/29] " Mauro Carvalho Chehab
2013-11-02 17:10 ` Antti Palosaari
2013-11-02 13:31 ` [PATCHv2 15/29] stb0899_drv: " Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 16/29] stv0367: " Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 17/29] stv090x: " Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 18/29] av7110_hw: " Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 19/29] tuners: " Mauro Carvalho Chehab
2013-11-02 17:12 ` Antti Palosaari [this message]
2013-11-02 17:25 ` Hans Verkuil
2013-11-02 21:15 ` Mauro Carvalho Chehab
2013-11-02 21:53 ` Hans Verkuil
2013-11-02 21:59 ` Hans Verkuil
2013-11-03 0:21 ` Mauro Carvalho Chehab
2013-11-03 9:12 ` Mauro Carvalho Chehab
2013-11-03 11:54 ` Antti Palosaari
2013-11-04 13:26 ` Hans Verkuil
2013-11-04 14:24 ` Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 20/29] tuner-xc2028: " Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 21/29] cimax2: " Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 22/29] v4l2-async: " Mauro Carvalho Chehab
2013-11-04 13:15 ` Hans Verkuil
2013-11-05 11:36 ` Mauro Carvalho Chehab
2013-11-05 11:42 ` Sylwester Nawrocki
2013-11-05 12:03 ` Mauro Carvalho Chehab
2013-11-05 12:35 ` Hans Verkuil
2013-11-05 13:16 ` Mauro Carvalho Chehab
2013-11-05 14:18 ` Hans Verkuil
2013-11-02 13:31 ` [PATCHv2 23/29] cxusb: " Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 24/29] dibusb-common: " Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 25/29] dw2102: " Mauro Carvalho Chehab
2013-11-02 13:31 ` [PATCHv2 26/29] af9015: " Mauro Carvalho Chehab
2013-11-02 17:05 ` Antti Palosaari
2013-11-02 13:31 ` [PATCHv2 27/29] af9035: " Mauro Carvalho Chehab
2013-11-02 17:19 ` Antti Palosaari
2013-11-02 13:31 ` [PATCHv2 28/29] mxl111sf: " Mauro Carvalho Chehab
2013-11-04 0:50 ` Michael Krufky
2013-11-04 10:58 ` Mauro Carvalho Chehab
2013-11-04 11:04 ` Michael Krufky
2013-11-02 13:31 ` [PATCHv2 29/29] lirc_zilog: " Mauro Carvalho Chehab
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