Subject: Re: [PATCH v2 06/11] dvb-frontends: reduce stack size in i2c access

From: Mauro Carvalho Chehab <[email-masked]>
Date: Sat, 24 Jun 2017 16:49:33 -0300

Em Wed, 14 Jun 2017 23:15:41 +0200
Arnd Bergmann <[email-masked]> escreveu:

> A typical code fragment was copied across many dvb-frontend
> drivers and causes large stack frames when built with
> -fsanitize-address-use-after-scope, e.g.
> 
> drivers/media/dvb-frontends/cxd2841er.c:3225:1: error: the frame size of 3992 bytes is larger than 3072 bytes [-Werror=frame-larger-than=]
> drivers/media/dvb-frontends/cxd2841er.c:3404:1: error: the frame size of 3136 bytes is larger than 3072 bytes [-Werror=frame-larger-than=]
> drivers/media/dvb-frontends/stv0367.c:3143:1: error: the frame size of 4016 bytes is larger than 3072 bytes [-Werror=frame-larger-than=]
> drivers/media/dvb-frontends/stv090x.c:3430:1: error: the frame size of 5312 bytes is larger than 3072 bytes [-Werror=frame-larger-than=]
> drivers/media/dvb-frontends/stv090x.c:4248:1: error: the frame size of 4872 bytes is larger than 3072 bytes [-Werror=frame-larger-than=]
> 
> By marking the register access functions as noinline_if_stackbloat,
> we can completely avoid this problem.
> 
> Signed-off-by: Arnd Bergmann <[email-masked]>

Feel free to add my ack to patches 6 and 7 of this series:

Acked-by: Mauro Carvalho Chehab <[email-masked]>

> ---
>  drivers/media/dvb-frontends/ascot2e.c       |  3 ++-
>  drivers/media/dvb-frontends/cxd2841er.c     |  4 ++--
>  drivers/media/dvb-frontends/drx39xyj/drxj.c | 14 +++++++-------
>  drivers/media/dvb-frontends/helene.c        |  4 ++--
>  drivers/media/dvb-frontends/horus3a.c       |  2 +-
>  drivers/media/dvb-frontends/itd1000.c       |  2 +-
>  drivers/media/dvb-frontends/mt312.c         |  2 +-
>  drivers/media/dvb-frontends/si2165.c        | 14 +++++++-------
>  drivers/media/dvb-frontends/stb0899_drv.c   |  2 +-
>  drivers/media/dvb-frontends/stb6100.c       |  2 +-
>  drivers/media/dvb-frontends/stv0367.c       |  2 +-
>  drivers/media/dvb-frontends/stv090x.c       |  2 +-
>  drivers/media/dvb-frontends/stv6110.c       |  2 +-
>  drivers/media/dvb-frontends/stv6110x.c      |  2 +-
>  drivers/media/dvb-frontends/tda8083.c       |  2 +-
>  drivers/media/dvb-frontends/zl10039.c       |  2 +-
>  16 files changed, 31 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/media/dvb-frontends/ascot2e.c b/drivers/media/dvb-frontends/ascot2e.c
> index 0ee0df53b91b..da1d1fc03c5e 100644
> --- a/drivers/media/dvb-frontends/ascot2e.c
> +++ b/drivers/media/dvb-frontends/ascot2e.c
> @@ -153,7 +153,8 @@ static int ascot2e_write_regs(struct ascot2e_priv *priv,
>  	return 0;
>  }
>  
> -static int ascot2e_write_reg(struct ascot2e_priv *priv, u8 reg, u8 val)
> +static noinline_if_stackbloat int ascot2e_write_reg(struct ascot2e_priv *priv,
> +						u8 reg, u8 val)
>  {
>  	return ascot2e_write_regs(priv, reg, &val, 1);
>  }
> diff --git a/drivers/media/dvb-frontends/cxd2841er.c b/drivers/media/dvb-frontends/cxd2841er.c
> index ce37dc2e89c7..6b851a948ce0 100644
> --- a/drivers/media/dvb-frontends/cxd2841er.c
> +++ b/drivers/media/dvb-frontends/cxd2841er.c
> @@ -258,7 +258,7 @@ static int cxd2841er_write_regs(struct cxd2841er_priv *priv,
>  	return 0;
>  }
>  
> -static int cxd2841er_write_reg(struct cxd2841er_priv *priv,
> +static noinline_if_stackbloat int cxd2841er_write_reg(struct cxd2841er_priv *priv,
>  			       u8 addr, u8 reg, u8 val)
>  {
>  	return cxd2841er_write_regs(priv, addr, reg, &val, 1);
> @@ -306,7 +306,7 @@ static int cxd2841er_read_regs(struct cxd2841er_priv *priv,
>  	return 0;
>  }
>  
> -static int cxd2841er_read_reg(struct cxd2841er_priv *priv,
> +static noinline_if_stackbloat int cxd2841er_read_reg(struct cxd2841er_priv *priv,
>  			      u8 addr, u8 reg, u8 *val)
>  {
>  	return cxd2841er_read_regs(priv, addr, reg, val, 1);
> diff --git a/drivers/media/dvb-frontends/drx39xyj/drxj.c b/drivers/media/dvb-frontends/drx39xyj/drxj.c
> index 14040c915dbb..ec5b13ca630b 100644
> --- a/drivers/media/dvb-frontends/drx39xyj/drxj.c
> +++ b/drivers/media/dvb-frontends/drx39xyj/drxj.c
> @@ -1516,7 +1516,7 @@ static int drxdap_fasi_read_block(struct i2c_device_addr *dev_addr,
>  *
>  ******************************/
>  
> -static int drxdap_fasi_read_reg16(struct i2c_device_addr *dev_addr,
> +static noinline_if_stackbloat int drxdap_fasi_read_reg16(struct i2c_device_addr *dev_addr,
>  					 u32 addr,
>  					 u16 *data, u32 flags)
>  {
> @@ -1549,7 +1549,7 @@ static int drxdap_fasi_read_reg16(struct i2c_device_addr *dev_addr,
>  *
>  ******************************/
>  
> -static int drxdap_fasi_read_reg32(struct i2c_device_addr *dev_addr,
> +static noinline_if_stackbloat int drxdap_fasi_read_reg32(struct i2c_device_addr *dev_addr,
>  					 u32 addr,
>  					 u32 *data, u32 flags)
>  {
> @@ -1722,7 +1722,7 @@ static int drxdap_fasi_write_block(struct i2c_device_addr *dev_addr,
>  *
>  ******************************/
>  
> -static int drxdap_fasi_write_reg16(struct i2c_device_addr *dev_addr,
> +static noinline_if_stackbloat int drxdap_fasi_write_reg16(struct i2c_device_addr *dev_addr,
>  					  u32 addr,
>  					  u16 data, u32 flags)
>  {
> @@ -1795,7 +1795,7 @@ static int drxdap_fasi_read_modify_write_reg16(struct i2c_device_addr *dev_addr,
>  *
>  ******************************/
>  
> -static int drxdap_fasi_write_reg32(struct i2c_device_addr *dev_addr,
> +static noinline_if_stackbloat int drxdap_fasi_write_reg32(struct i2c_device_addr *dev_addr,
>  					  u32 addr,
>  					  u32 data, u32 flags)
>  {
> @@ -2172,7 +2172,7 @@ int drxj_dap_atomic_read_write_block(struct i2c_device_addr *dev_addr,
>  * \fn int drxj_dap_atomic_read_reg32()
>  * \brief Atomic read of 32 bits words
>  */
> -static
> +static noinline_if_stackbloat
>  int drxj_dap_atomic_read_reg32(struct i2c_device_addr *dev_addr,
>  				     u32 addr,
>  				     u32 *data, u32 flags)
> @@ -4192,7 +4192,7 @@ int drxj_dap_scu_atomic_read_write_block(struct i2c_device_addr *dev_addr, u32 a
>  * \fn int DRXJ_DAP_AtomicReadReg16()
>  * \brief Atomic read of 16 bits words
>  */
> -static
> +static noinline_if_stackbloat
>  int drxj_dap_scu_atomic_read_reg16(struct i2c_device_addr *dev_addr,
>  					 u32 addr,
>  					 u16 *data, u32 flags)
> @@ -4220,7 +4220,7 @@ int drxj_dap_scu_atomic_read_reg16(struct i2c_device_addr *dev_addr,
>  * \fn int drxj_dap_scu_atomic_write_reg16()
>  * \brief Atomic read of 16 bits words
>  */
> -static
> +static noinline_if_stackbloat
>  int drxj_dap_scu_atomic_write_reg16(struct i2c_device_addr *dev_addr,
>  					  u32 addr,
>  					  u16 data, u32 flags)
> diff --git a/drivers/media/dvb-frontends/helene.c b/drivers/media/dvb-frontends/helene.c
> index 4bf5a551ba40..849a18a837d0 100644
> --- a/drivers/media/dvb-frontends/helene.c
> +++ b/drivers/media/dvb-frontends/helene.c
> @@ -329,7 +329,7 @@ static int helene_write_regs(struct helene_priv *priv,
>  	return 0;
>  }
>  
> -static int helene_write_reg(struct helene_priv *priv, u8 reg, u8 val)
> +static noinline_if_stackbloat int helene_write_reg(struct helene_priv *priv, u8 reg, u8 val)
>  {
>  	return helene_write_regs(priv, reg, &val, 1);
>  }
> @@ -374,7 +374,7 @@ static int helene_read_regs(struct helene_priv *priv,
>  	return 0;
>  }
>  
> -static int helene_read_reg(struct helene_priv *priv, u8 reg, u8 *val)
> +static noinline_if_stackbloat int helene_read_reg(struct helene_priv *priv, u8 reg, u8 *val)
>  {
>  	return helene_read_regs(priv, reg, val, 1);
>  }
> diff --git a/drivers/media/dvb-frontends/horus3a.c b/drivers/media/dvb-frontends/horus3a.c
> index 68d759c4c52e..f879af6c3188 100644
> --- a/drivers/media/dvb-frontends/horus3a.c
> +++ b/drivers/media/dvb-frontends/horus3a.c
> @@ -87,7 +87,7 @@ static int horus3a_write_regs(struct horus3a_priv *priv,
>  	return 0;
>  }
>  
> -static int horus3a_write_reg(struct horus3a_priv *priv, u8 reg, u8 val)
> +static noinline_if_stackbloat int horus3a_write_reg(struct horus3a_priv *priv, u8 reg, u8 val)
>  {
>  	return horus3a_write_regs(priv, reg, &val, 1);
>  }
> diff --git a/drivers/media/dvb-frontends/itd1000.c b/drivers/media/dvb-frontends/itd1000.c
> index 5bb1e73a10b4..8bd6d04362cc 100644
> --- a/drivers/media/dvb-frontends/itd1000.c
> +++ b/drivers/media/dvb-frontends/itd1000.c
> @@ -93,7 +93,7 @@ static int itd1000_read_reg(struct itd1000_state *state, u8 reg)
>  	return val;
>  }
>  
> -static inline int itd1000_write_reg(struct itd1000_state *state, u8 r, u8 v)
> +static noinline_if_stackbloat int itd1000_write_reg(struct itd1000_state *state, u8 r, u8 v)
>  {
>  	int ret = itd1000_write_regs(state, r, &v, 1);
>  	state->shadow[r] = v;
> diff --git a/drivers/media/dvb-frontends/mt312.c b/drivers/media/dvb-frontends/mt312.c
> index 961b9a2508e0..d7a701da598a 100644
> --- a/drivers/media/dvb-frontends/mt312.c
> +++ b/drivers/media/dvb-frontends/mt312.c
> @@ -139,7 +139,7 @@ static inline int mt312_readreg(struct mt312_state *state,
>  	return mt312_read(state, reg, val, 1);
>  }
>  
> -static inline int mt312_writereg(struct mt312_state *state,
> +static noinline_if_stackbloat int mt312_writereg(struct mt312_state *state,
>  				 const enum mt312_reg_addr reg, const u8 val)
>  {
>  	return mt312_write(state, reg, &val, 1);
> diff --git a/drivers/media/dvb-frontends/si2165.c b/drivers/media/dvb-frontends/si2165.c
> index 528b82a5dd46..8b1ac134f9d8 100644
> --- a/drivers/media/dvb-frontends/si2165.c
> +++ b/drivers/media/dvb-frontends/si2165.c
> @@ -140,7 +140,7 @@ static int si2165_read(struct si2165_state *state,
>  	return 0;
>  }
>  
> -static int si2165_readreg8(struct si2165_state *state,
> +static noinline_if_stackbloat int si2165_readreg8(struct si2165_state *state,
>  		       const u16 reg, u8 *val)
>  {
>  	unsigned int val_tmp;
> @@ -150,7 +150,7 @@ static int si2165_readreg8(struct si2165_state *state,
>  	return ret;
>  }
>  
> -static int si2165_readreg16(struct si2165_state *state,
> +static noinline_if_stackbloat int si2165_readreg16(struct si2165_state *state,
>  		       const u16 reg, u16 *val)
>  {
>  	u8 buf[2];
> @@ -161,26 +161,26 @@ static int si2165_readreg16(struct si2165_state *state,
>  	return ret;
>  }
>  
> -static int si2165_writereg8(struct si2165_state *state, const u16 reg, u8 val)
> +static noinline_if_stackbloat int si2165_writereg8(struct si2165_state *state, const u16 reg, u8 val)
>  {
>  	return regmap_write(state->regmap, reg, val);
>  }
>  
> -static int si2165_writereg16(struct si2165_state *state, const u16 reg, u16 val)
> +static noinline_if_stackbloat int si2165_writereg16(struct si2165_state *state, const u16 reg, u16 val)
>  {
>  	u8 buf[2] = { val & 0xff, (val >> 8) & 0xff };
>  
>  	return si2165_write(state, reg, buf, 2);
>  }
>  
> -static int si2165_writereg24(struct si2165_state *state, const u16 reg, u32 val)
> +static noinline_if_stackbloat int si2165_writereg24(struct si2165_state *state, const u16 reg, u32 val)
>  {
>  	u8 buf[3] = { val & 0xff, (val >> 8) & 0xff, (val >> 16) & 0xff };
>  
>  	return si2165_write(state, reg, buf, 3);
>  }
>  
> -static int si2165_writereg32(struct si2165_state *state, const u16 reg, u32 val)
> +static noinline_if_stackbloat int si2165_writereg32(struct si2165_state *state, const u16 reg, u32 val)
>  {
>  	u8 buf[4] = {
>  		val & 0xff,
> @@ -191,7 +191,7 @@ static int si2165_writereg32(struct si2165_state *state, const u16 reg, u32 val)
>  	return si2165_write(state, reg, buf, 4);
>  }
>  
> -static int si2165_writereg_mask8(struct si2165_state *state, const u16 reg,
> +static noinline_if_stackbloat int si2165_writereg_mask8(struct si2165_state *state, const u16 reg,
>  				 u8 val, u8 mask)
>  {
>  	if (mask != 0xff) {
> diff --git a/drivers/media/dvb-frontends/stb0899_drv.c b/drivers/media/dvb-frontends/stb0899_drv.c
> index 02347598277a..9258085b8d35 100644
> --- a/drivers/media/dvb-frontends/stb0899_drv.c
> +++ b/drivers/media/dvb-frontends/stb0899_drv.c
> @@ -537,7 +537,7 @@ int stb0899_write_regs(struct stb0899_state *state, unsigned int reg, u8 *data,
>  	return 0;
>  }
>  
> -int stb0899_write_reg(struct stb0899_state *state, unsigned int reg, u8 data)
> +noinline_if_stackbloat int stb0899_write_reg(struct stb0899_state *state, unsigned int reg, u8 data)
>  {
>  	return stb0899_write_regs(state, reg, &data, 1);
>  }
> diff --git a/drivers/media/dvb-frontends/stb6100.c b/drivers/media/dvb-frontends/stb6100.c
> index 17a955d0031b..675dffe1ef20 100644
> --- a/drivers/media/dvb-frontends/stb6100.c
> +++ b/drivers/media/dvb-frontends/stb6100.c
> @@ -224,7 +224,7 @@ static int stb6100_write_reg_range(struct stb6100_state *state, u8 buf[], int st
>  	return 0;
>  }
>  
> -static int stb6100_write_reg(struct stb6100_state *state, u8 reg, u8 data)
> +static noinline_if_stackbloat int stb6100_write_reg(struct stb6100_state *state, u8 reg, u8 data)
>  {
>  	if (unlikely(reg >= STB6100_NUMREGS)) {
>  		dprintk(verbose, FE_ERROR, 1, "Invalid register offset 0x%x", reg);
> diff --git a/drivers/media/dvb-frontends/stv0367.c b/drivers/media/dvb-frontends/stv0367.c
> index fd49c436a36d..2316c0bb3e21 100644
> --- a/drivers/media/dvb-frontends/stv0367.c
> +++ b/drivers/media/dvb-frontends/stv0367.c
> @@ -798,7 +798,7 @@ int stv0367_writeregs(struct stv0367_state *state, u16 reg, u8 *data, int len)
>  	return (ret != 1) ? -EREMOTEIO : 0;
>  }
>  
> -static int stv0367_writereg(struct stv0367_state *state, u16 reg, u8 data)
> +static noinline_if_stackbloat int stv0367_writereg(struct stv0367_state *state, u16 reg, u8 data)
>  {
>  	return stv0367_writeregs(state, reg, &data, 1);
>  }
> diff --git a/drivers/media/dvb-frontends/stv090x.c b/drivers/media/dvb-frontends/stv090x.c
> index 7ef469c0c866..8afecc2e3637 100644
> --- a/drivers/media/dvb-frontends/stv090x.c
> +++ b/drivers/media/dvb-frontends/stv090x.c
> @@ -753,7 +753,7 @@ static int stv090x_write_regs(struct stv090x_state *state, unsigned int reg, u8
>  	return 0;
>  }
>  
> -static int stv090x_write_reg(struct stv090x_state *state, unsigned int reg, u8 data)
> +static noinline_if_stackbloat int stv090x_write_reg(struct stv090x_state *state, unsigned int reg, u8 data)
>  {
>  	return stv090x_write_regs(state, reg, &data, 1);
>  }
> diff --git a/drivers/media/dvb-frontends/stv6110.c b/drivers/media/dvb-frontends/stv6110.c
> index e4fd9c1b0560..ddef3a912615 100644
> --- a/drivers/media/dvb-frontends/stv6110.c
> +++ b/drivers/media/dvb-frontends/stv6110.c
> @@ -137,7 +137,7 @@ static int stv6110_read_regs(struct dvb_frontend *fe, u8 regs[],
>  	return 0;
>  }
>  
> -static int stv6110_read_reg(struct dvb_frontend *fe, int start)
> +static noinline_if_stackbloat int stv6110_read_reg(struct dvb_frontend *fe, int start)
>  {
>  	u8 buf[] = { 0 };
>  	stv6110_read_regs(fe, buf, start, 1);
> diff --git a/drivers/media/dvb-frontends/stv6110x.c b/drivers/media/dvb-frontends/stv6110x.c
> index 66eba38f1014..80c7024971de 100644
> --- a/drivers/media/dvb-frontends/stv6110x.c
> +++ b/drivers/media/dvb-frontends/stv6110x.c
> @@ -95,7 +95,7 @@ static int stv6110x_write_regs(struct stv6110x_state *stv6110x, int start, u8 da
>  	return 0;
>  }
>  
> -static int stv6110x_write_reg(struct stv6110x_state *stv6110x, u8 reg, u8 data)
> +static noinline_if_stackbloat int stv6110x_write_reg(struct stv6110x_state *stv6110x, u8 reg, u8 data)
>  {
>  	return stv6110x_write_regs(stv6110x, reg, &data, 1);
>  }
> diff --git a/drivers/media/dvb-frontends/tda8083.c b/drivers/media/dvb-frontends/tda8083.c
> index aa3200d3c352..646f22aab24e 100644
> --- a/drivers/media/dvb-frontends/tda8083.c
> +++ b/drivers/media/dvb-frontends/tda8083.c
> @@ -88,7 +88,7 @@ static int tda8083_readregs (struct tda8083_state* state, u8 reg1, u8 *b, u8 len
>  	return ret == 2 ? 0 : -1;
>  }
>  
> -static inline u8 tda8083_readreg (struct tda8083_state* state, u8 reg)
> +static noinline_if_stackbloat u8 tda8083_readreg (struct tda8083_state* state, u8 reg)
>  {
>  	u8 val;
>  
> diff --git a/drivers/media/dvb-frontends/zl10039.c b/drivers/media/dvb-frontends/zl10039.c
> index 623355fc2666..0075725cb161 100644
> --- a/drivers/media/dvb-frontends/zl10039.c
> +++ b/drivers/media/dvb-frontends/zl10039.c
> @@ -130,7 +130,7 @@ static inline int zl10039_readreg(struct zl10039_state *state,
>  	return zl10039_read(state, reg, val, 1);
>  }
>  
> -static inline int zl10039_writereg(struct zl10039_state *state,
> +static noinline_if_stackbloat int zl10039_writereg(struct zl10039_state *state,
>  				const enum zl10039_reg_addr reg,
>  				const u8 val)
>  {

Thanks,
Mauro