Dynamic static allocation is evil, as Kernel stack is too low, and
compilation complains about it on some archs:
drivers/media/dvb-frontends/stb0899_drv.c:540:1: warning: 'stb0899_write_regs' 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: Michael Krufky <mkrufky@xxxxxxxxxxx>
Cc: Zoran Turalija <zoran.turalija@xxxxxxxxx>
Cc: "Reinhard Nißl" <rnissl@xxxxxx>
---
drivers/media/dvb-frontends/stb0899_drv.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/media/dvb-frontends/stb0899_drv.c b/drivers/media/dvb-frontends/stb0899_drv.c
index 3dd5714eadba..9df77899b219 100644
--- a/drivers/media/dvb-frontends/stb0899_drv.c
+++ b/drivers/media/dvb-frontends/stb0899_drv.c
@@ -499,7 +499,7 @@ err:
int stb0899_write_regs(struct stb0899_state *state, unsigned int reg, u8 *data, u32 count)
{
int ret;
- u8 buf[2 + count];
+ u8 buf[80];
struct i2c_msg i2c_msg = {
.addr = state->config->demod_address,
.flags = 0,
@@ -507,6 +507,13 @@ int stb0899_write_regs(struct stb0899_state *state, unsigned int reg, u8 *data,
.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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