[PATCH 4.4 84/88] media: dvb-frontends: fix i2c access helpers for KASAN

Greg Kroah-Hartman
2018-12-14T12:17:12Z

From: Arnd Bergmann <arnd@arndb.de>

commit 3cd890dbe2a4f14cc44c85bb6cf37e5e22d4dd0e upstream.

A typical code fragment was copied across many dvb-frontend drivers and
causes large stack frames when built with with CONFIG_KASAN on gcc-5/6/7:

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=]

gcc-8 now solves this by consolidating the stack slots for the argument
variables, but on older compilers we can get the same behavior by taking
the pointer of a local variable rather than the inline function argument.

Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715

Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/media/dvb-frontends/ascot2e.c | 4 +++-
drivers/media/dvb-frontends/cxd2841er.c | 4 +++-
drivers/media/dvb-frontends/horus3a.c | 4 +++-
drivers/media/dvb-frontends/itd1000.c | 5 +++--
drivers/media/dvb-frontends/mt312.c | 5 ++++-
drivers/media/dvb-frontends/stb0899_drv.c | 3 ++-
drivers/media/dvb-frontends/stb6100.c | 6 ++++--
drivers/media/dvb-frontends/stv0367.c | 4 +++-
drivers/media/dvb-frontends/stv090x.c | 4 +++-
drivers/media/dvb-frontends/stv6110x.c | 4 +++-
drivers/media/dvb-frontends/zl10039.c | 4 +++-
11 files changed, 34 insertions(+), 13 deletions(-)

--- a/drivers/media/dvb-frontends/ascot2e.c
+++ b/drivers/media/dvb-frontends/ascot2e.c
@@ -155,7 +155,9 @@ static int ascot2e_write_regs(struct asc

static int ascot2e_write_reg(struct ascot2e_priv *priv, u8 reg, u8 val)
{
- return ascot2e_write_regs(priv, reg, &val, 1);
+ u8 tmp = val; /* see gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 */
+
+ return ascot2e_write_regs(priv, reg, &tmp, 1);
}

static int ascot2e_read_regs(struct ascot2e_priv *priv,
--- a/drivers/media/dvb-frontends/cxd2841er.c
+++ b/drivers/media/dvb-frontends/cxd2841er.c
@@ -241,7 +241,9 @@ static int cxd2841er_write_regs(struct c
static int cxd2841er_write_reg(struct cxd2841er_priv *priv,
u8 addr, u8 reg, u8 val)
{
- return cxd2841er_write_regs(priv, addr, reg, &val, 1);
+ u8 tmp = val; /* see gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 */
+
+ return cxd2841er_write_regs(priv, addr, reg, &tmp, 1);
}

static int cxd2841er_read_regs(struct cxd2841er_priv *priv,
--- a/drivers/media/dvb-frontends/horus3a.c
+++ b/drivers/media/dvb-frontends/horus3a.c
@@ -89,7 +89,9 @@ static int horus3a_write_regs(struct hor

static int horus3a_write_reg(struct horus3a_priv *priv, u8 reg, u8 val)
{
- return horus3a_write_regs(priv, reg, &val, 1);
+ u8 tmp = val; /* see gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 */
+
+ return horus3a_write_regs(priv, reg, &tmp, 1);
}

static int horus3a_enter_power_save(struct horus3a_priv *priv)
--- a/drivers/media/dvb-frontends/itd1000.c
+++ b/drivers/media/dvb-frontends/itd1000.c
@@ -99,8 +99,9 @@ static int itd1000_read_reg(struct itd10

static inline 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;
+ u8 tmp = v; /* see gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 */
+ int ret = itd1000_write_regs(state, r, &tmp, 1);
+ state->shadow[r] = tmp;
return ret;
}

--- a/drivers/media/dvb-frontends/mt312.c
+++ b/drivers/media/dvb-frontends/mt312.c
@@ -142,7 +142,10 @@ static inline int mt312_readreg(struct m
static inline int mt312_writereg(struct mt312_state *state,
const enum mt312_reg_addr reg, const u8 val)
{
- return mt312_write(state, reg, &val, 1);
+ u8 tmp = val; /* see gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 */
+
+
+ return mt312_write(state, reg, &tmp, 1);
}

static inline u32 mt312_div(u32 a, u32 b)
--- a/drivers/media/dvb-frontends/stb0899_drv.c
+++ b/drivers/media/dvb-frontends/stb0899_drv.c
@@ -552,7 +552,8 @@ int stb0899_write_regs(struct stb0899_st

int stb0899_write_reg(struct stb0899_state *state, unsigned int reg, u8 data)
{
- return stb0899_write_regs(state, reg, &data, 1);
+ u8 tmp = data;
+ return stb0899_write_regs(state, reg, &tmp, 1);
}

/*
--- a/drivers/media/dvb-frontends/stb6100.c
+++ b/drivers/media/dvb-frontends/stb6100.c
@@ -226,12 +226,14 @@ static int stb6100_write_reg_range(struc

static int stb6100_write_reg(struct stb6100_state *state, u8 reg, u8 data)
{
+ u8 tmp = data; /* see gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 */
+
if (unlikely(reg >= STB6100_NUMREGS)) {
dprintk(verbose, FE_ERROR, 1, "Invalid register offset 0x%x", reg);
return -EREMOTEIO;
}
- data = (data & stb6100_template[reg].mask) | stb6100_template[reg].set;
- return stb6100_write_reg_range(state, &data, reg, 1);
+ tmp = (tmp & stb6100_template[reg].mask) | stb6100_template[reg].set;
+ return stb6100_write_reg_range(state, &tmp, reg, 1);
}

--- a/drivers/media/dvb-frontends/stv0367.c
+++ b/drivers/media/dvb-frontends/stv0367.c
@@ -804,7 +804,9 @@ int stv0367_writeregs(struct stv0367_sta

static int stv0367_writereg(struct stv0367_state *state, u16 reg, u8 data)
{
- return stv0367_writeregs(state, reg, &data, 1);
+ 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)
--- a/drivers/media/dvb-frontends/stv090x.c
+++ b/drivers/media/dvb-frontends/stv090x.c
@@ -761,7 +761,9 @@ static int stv090x_write_regs(struct stv

static int stv090x_write_reg(struct stv090x_state *state, unsigned int reg, u8 data)
{
- return stv090x_write_regs(state, reg, &data, 1);
+ u8 tmp = data; /* see gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 */
+
+ return stv090x_write_regs(state, reg, &tmp, 1);
}

static int stv090x_i2c_gate_ctrl(struct stv090x_state *state, int enable)
--- a/drivers/media/dvb-frontends/stv6110x.c
+++ b/drivers/media/dvb-frontends/stv6110x.c
@@ -97,7 +97,9 @@ static int stv6110x_write_regs(struct st

static int stv6110x_write_reg(struct stv6110x_state *stv6110x, u8 reg, u8 data)
{
- return stv6110x_write_regs(stv6110x, reg, &data, 1);
+ u8 tmp = data; /* see gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 */
+
+ return stv6110x_write_regs(stv6110x, reg, &tmp, 1);
}

static int stv6110x_init(struct dvb_frontend *fe)
--- a/drivers/media/dvb-frontends/zl10039.c
+++ b/drivers/media/dvb-frontends/zl10039.c
@@ -138,7 +138,9 @@ static inline int zl10039_writereg(struc
const enum zl10039_reg_addr reg,
const u8 val)
{
- return zl10039_write(state, reg, &val, 1);
+ const u8 tmp = val; /* see gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 */
+
+ return zl10039_write(state, reg, &tmp, 1);
}

static int zl10039_init(struct dvb_frontend *fe)