At Sat, 17 Oct 2009 08:33:47 +0200 (CEST), Julia Lawall wrote:

From: Julia Lawall julia@diku.dk

If the NULL test on h is needed in snd_harmony_mixer_init, then the dereference should be after the NULL test.

Actually, there is a sequence of calls: snd_harmony_create, then snd_harmony_pcm_init, and then snd_harmony_mixer_init. snd_harmony_create initializes h, but may indeed leave it as NULL. There was no NULL test at the beginning of snd_harmony_pcm_init, so I have added one. The NULL test in snd_harmony_mixer_init is then not necessary, but in case the ordering of the calls changes, I have left it, and moved the dereference after it.

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

// <smpl> @match exists@ expression x, E; identifier fld; @@

• x->fld ... when != (x = E|&x)
• x == NULL

// </smpl>

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

Applied this one, too. Thanks.

Takashi

---

sound/parisc/harmony.c | 6 +++++- 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/sound/parisc/harmony.c b/sound/parisc/harmony.c index e924492..f47f9e2 100644 --- a/sound/parisc/harmony.c +++ b/sound/parisc/harmony.c @@ -624,6 +624,9 @@ snd_harmony_pcm_init(struct snd_harmony *h) struct snd_pcm *pcm; int err;

• if (snd_BUG_ON(!h))

• return -EINVAL;
  

• harmony_disable_interrupts(h);

  err = snd_pcm_new(h->card, "harmony", 0, 1, 1, &pcm);
  

@@ -865,11 +868,12 @@ snd_harmony_mixer_reset(struct snd_harmony *h) static int __devinit snd_harmony_mixer_init(struct snd_harmony *h) {

• struct snd_card *card = h->card;

• struct snd_card *card; int idx, err;

  if (snd_BUG_ON(!h)) return -EINVAL;

• card = h->card; strcpy(card->mixername, "Harmony Gain control interface");

  for (idx = 0; idx < HARMONY_CONTROLS; idx++) {