On Sun, 13 Dec 2009, walter harms wrote:

Julia Lawall schrieb:

...

From: Julia Lawall julia@diku.dk

sizeof(codec->reg_cache) is just the size of the pointer. Elsewhere in the file, codec->reg_cache is used with sizeof(wm8900_reg_defaults), so the code is changed to do the same here.

A simplified version of the semantic patch that finds this problem is as follows: (http://coccinelle.lip6.fr/)

// <smpl> @@ expression *x; expression f; type T; @@

*f(...,(T)x,...) // </smpl>

Signed-off-by: Julia Lawall julia@diku.dk

---

sound/soc/codecs/wm8900.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/sound/soc/codecs/wm8900.c b/sound/soc/codecs/wm8900.c index c9438dd..dbc368c 100644 --- a/sound/soc/codecs/wm8900.c +++ b/sound/soc/codecs/wm8900.c @@ -199,7 +199,7 @@ static void wm8900_reset(struct snd_soc_codec *codec) snd_soc_write(codec, WM8900_REG_RESET, 0);

memcpy(codec->reg_cache, wm8900_reg_defaults,

•       sizeof(codec->reg_cache));
  

•       sizeof(wm8900_reg_defaults));
  

}

I do not think that this was the intention of the original author, I guess the idea behind sizeof(*codec->reg_cache) was to protect the area behind it (in case wm8900_reg_defaults are badly defined).

sizeof(codec->reg_cache) is the size of a pointer (void *). sizeof(*codec->reg_cache) is then the size of void. wm8900_reg_defaults is a static constant array defined a few lines before this code:

static const u16 wm8900_reg_defaults[WM8900_MAXREG] = { ... };

Later in the same file there is:

cache = kmemdup(codec->reg_cache, sizeof(wm8900_reg_defaults), GFP_KERNEL);

and codec->reg_cache is initialized as follows:

codec->reg_cache = &wm8900->reg_cache[0];

The reg_cache field in wm8900 is declared as u16 reg_cache[WM8900_MAXREG];

julia