[PATCH 3.10 149/173] media: lirc_zilog: Dont use dynamic static allocation

Greg Kroah-Hartman
2013-12-02T19:12:12Z

From: Mauro Carvalho Chehab <m.chehab@samsung.com>

commit ac5b4b6bf0c84c48d7e2e3fce22e35b04282ba76 upstream.

Dynamic static allocation is evil, as Kernel stack is too low, and
ompilation complains about it on some archs:
drivers/staging/media/lirc/lirc_zilog.c:967:1: warning: 'read' uses dynamic stack allocation [enabled by default]
Instead, let's enforce a limit for the buffer to be 64. That should
be more than enough.

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/staging/media/lirc/lirc_zilog.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

--- a/drivers/staging/media/lirc/lirc_zilog.c
+++ b/drivers/staging/media/lirc/lirc_zilog.c
@@ -61,6 +61,9 @@
#include <media/lirc_dev.h>
#include <media/lirc.h>

+/* Max transfer size done by I2C transfer functions */
+#define MAX_XFER_SIZE 64
+
struct IR;

struct IR_rx {
@@ -941,7 +944,14 @@ static ssize_t read(struct file *filep,
schedule();
set_current_state(TASK_INTERRUPTIBLE);
} else {
- unsigned char buf[rbuf->chunk_size];
+ unsigned char buf[MAX_XFER_SIZE];
+
+ if (rbuf->chunk_size > sizeof(buf)) {
+ zilog_error("chunk_size is too big (%d)!\n",
+ rbuf->chunk_size);
+ ret = -EINVAL;
+ break;
+ }
m = lirc_buffer_read(rbuf, buf);
if (m == rbuf->chunk_size) {
ret = copy_to_user((void *)outbuf+written, buf,