Dynamic static allocation is evil, as Kernel stack is too low, and
compilation complains about it on some archs:
drivers/media/dvb-frontends/stv090x.c:750:1: warning: 'stv090x_write_regs.constprop.6' 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: Manu Abraham <manu@xxxxxxxxxxx>
Cc: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
Cc: Andreas Regel <andreas.regel@xxxxxx>
---
drivers/media/dvb-frontends/stv090x.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/media/dvb-frontends/stv090x.c b/drivers/media/dvb-frontends/stv090x.c
index 56d470ad5a82..7484b01a9f13 100644
--- a/drivers/media/dvb-frontends/stv090x.c
+++ b/drivers/media/dvb-frontends/stv090x.c
@@ -722,9 +722,16 @@ static int stv090x_write_regs(struct stv090x_state *state, unsigned int reg, u8
{
const struct stv090x_config *config = state->config;
int ret;
- u8 buf[2 + count];
+ u8 buf[80];
struct i2c_msg i2c_msg = { .addr = config->address, .flags = 0, .buf = buf, .len = 2 + count };
+ if (2 + count > sizeof(buf)) {
+ printk(KERN_WARNING
+ "%s: i2c wr reg=%04x: len=%d is too big!\n",
+ KBUILD_MODNAME, reg, count);
+ return -EREMOTEIO;
+ }
+
buf[0] = reg >> 8;
buf[1] = reg & 0xff;
memcpy(&buf[2], data, count);
--
1.8.3.1
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