Commit e8e0929d authored Oct 17, 2009 by Julia Lawall Committed by Takashi Iwai Oct 30, 2009

ALSA: sound/parisc: Move dereference after NULL test

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>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

parent 4b3be6af

sound/parisc/harmony.c

+5 −1

Original line number	Original line	Diff line number	Diff line
	@@ -624,6 +624,9 @@ snd_harmony_pcm_init(struct snd_harmony *h)
	struct snd_pcm *pcm;		struct snd_pcm *pcm;
	int err;		int err;

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

	harmony_disable_interrupts(h);		harmony_disable_interrupts(h);

	err = snd_pcm_new(h->card, "harmony", 0, 1, 1, &pcm);		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		static int __devinit
	snd_harmony_mixer_init(struct snd_harmony *h)		snd_harmony_mixer_init(struct snd_harmony *h)
	{		{
	struct snd_card *card = h->card;		struct snd_card *card;
	int idx, err;		int idx, err;

	if (snd_BUG_ON(!h))		if (snd_BUG_ON(!h))
	return -EINVAL;		return -EINVAL;
			card = h->card;
	strcpy(card->mixername, "Harmony Gain control interface");		strcpy(card->mixername, "Harmony Gain control interface");

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