This is a note to let you know that I've just added the patch titled
media: stv090x: Don't use dynamic static allocation
to the 3.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
media-stv090x-don-t-use-dynamic-static-allocation.patch
and it can be found in the queue-3.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f7a35df15b1f7de7823946aebc9164854e66ea07 Mon Sep 17 00:00:00 2001
From: Mauro Carvalho Chehab <m.chehab@xxxxxxxxxxx>
Date: Sat, 2 Nov 2013 05:18:49 -0300
Subject: media: stv090x: Don't use dynamic static allocation
From: Mauro Carvalho Chehab <m.chehab@xxxxxxxxxxx>
commit f7a35df15b1f7de7823946aebc9164854e66ea07 upstream.
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 64 bytes for the control URBs.
So, it seem safe to use 64 bytes as the hard limit for all those devices.
On most cases, the limit is a way lower than that, but this limit
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>
Reviewed-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/media/dvb-frontends/stv090x.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
--- a/drivers/media/dvb-frontends/stv090x.c
+++ b/drivers/media/dvb-frontends/stv090x.c
@@ -35,6 +35,9 @@
#include "stv090x.h"
#include "stv090x_priv.h"
+/* Max transfer size done by I2C transfer functions */
+#define MAX_XFER_SIZE 64
+
static unsigned int verbose;
module_param(verbose, int, 0644);
@@ -722,9 +725,16 @@ static int stv090x_write_regs(struct stv
{
const struct stv090x_config *config = state->config;
int ret;
- u8 buf[2 + count];
+ u8 buf[MAX_XFER_SIZE];
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 -EINVAL;
+ }
+
buf[0] = reg >> 8;
buf[1] = reg & 0xff;
memcpy(&buf[2], data, count);
Patches currently in stable-queue which might be from m.chehab@xxxxxxxxxxx are
queue-3.12/media-af9015-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-dw2102-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-af9035-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-stb0899_drv-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-dibusb-common-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-cx18-struct-i2c_client-is-too-big-for-stack.patch
queue-3.12/media-tuner-xc2028-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-cimax2-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-tuners-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-v4l2-async-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-dvb-frontends-again-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-dvb-frontends-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-stv090x-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-s5h1420-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-av7110_hw-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-stv0367-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-lirc_zilog-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-cxusb-don-t-use-dynamic-static-allocation.patch
queue-3.12/media-mxl111sf-don-t-use-dynamic-static-allocation.patch
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