Dynamic static allocation is evil, as Kernel stack is too low, and
compilation complains about it on some archs:
drivers/media/dvb-frontends/stv0367.c:791:1: warning: 'stv0367_writeregs.constprop.4' 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@xxxxxxxxxxx>
Cc: Jiri Kosina <jkosina@xxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
---
drivers/media/dvb-frontends/stv0367.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/media/dvb-frontends/stv0367.c b/drivers/media/dvb-frontends/stv0367.c
index 7b6dba3ce55e..28294b3be319 100644
--- a/drivers/media/dvb-frontends/stv0367.c
+++ b/drivers/media/dvb-frontends/stv0367.c
@@ -767,7 +767,7 @@ static struct st_register def0367cab[STV0367CAB_NBREGS] = {
static
int stv0367_writeregs(struct stv0367_state *state, u16 reg, u8 *data, int len)
{
- u8 buf[len + 2];
+ u8 buf[80];
struct i2c_msg msg = {
.addr = state->config->demod_address,
.flags = 0,
@@ -776,6 +776,14 @@ int stv0367_writeregs(struct stv0367_state *state, u16 reg, u8 *data, int len)
};
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 -EREMOTEIO;
+ }
+
+
buf[0] = MSB(reg);
buf[1] = LSB(reg);
memcpy(buf + 2, data, len);
--
1.8.3.1
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