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.che...@samsung.com>
Cc: Jiri Kosina <jkos...@suse.cz>
Cc: Geert Uytterhoeven <ge...@linux-m68k.org>
---
 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

--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to