[ This is an old patch. I'm working on some new Smatch stuff and I'm looking at this code, and I don't see how it's possible for this code to work. I must be missing something and it would help me if someone could explain to me what's going on so I can fix my software. - dan ]

Hello Peter Hsiang,

The patch dad31ec133ad: "ASoC: Add EQ and filter to max98095 CODEC driver" from Apr 19, 2011, leads to the following static checker warning:

sound/soc/codecs/max98095.c:1524 max98095_put_eq_enum() warn: constraint overflow 'max98095->eq_texts' required = '(struct max98095_priv)->eq_textcnt'

The error message is saying that Smatch expects we should verify that the index into the max98095->eq_texts[] array is less than max98095->eq_textcnt.

sound/soc/codecs/max98095.c 1494 static int max98095_put_eq_enum(struct snd_kcontrol *kcontrol, 1495 struct snd_ctl_elem_value *ucontrol) 1496 { 1497 struct snd_soc_codec *codec = snd_soc_kcontrol_codec(kcontrol); 1498 struct max98095_priv *max98095 = snd_soc_codec_get_drvdata(codec); 1499 struct max98095_pdata *pdata = max98095->pdata; 1500 int channel = max98095_get_eq_channel(kcontrol->id.name); 1501 struct max98095_cdata *cdata; 1502 unsigned int sel = ucontrol->value.enumerated.item[0]; 1503 struct max98095_eq_cfg *coef_set; 1504 int fs, best, best_val, i; 1505 int regmask, regsave; 1506 1507 if (WARN_ON(channel > 1)) 1508 return -EINVAL; 1509 1510 if (!pdata || !max98095->eq_textcnt) ^^^^^^^^^^^^^^^^^^^^^

Here we check that max98095->eq_textcnt is non-zero.

1511 return 0; 1512 1513 if (sel >= pdata->eq_cfgcnt) ^^^^^^^^^^^^^^^^^^^^^^^ Check here

1514 return -EINVAL; 1515 1516 cdata = &max98095->dai[channel]; 1517 cdata->eq_sel = sel; 1518 fs = cdata->rate; 1519 1520 /* Find the selected configuration with nearest sample rate */ 1521 best = 0; 1522 best_val = INT_MAX; 1523 for (i = 0; i < pdata->eq_cfgcnt; i++) { ^^^^^^^^^^^^^^^^ According to Smatch the only place where pdata->eq_cfgcnt get set is from the assignment in max98095_i2c_probe() where we do:

max98095->pdata = i2c->dev.platform_data;

I don't know how i2c->dev.platform_data gets set. I would have thought it would just be a zeroed buffer.

1524 if (strcmp(pdata->eq_cfg[i].name, max98095->eq_texts[sel]) == 0 && ^^^^^^^^^^^^^ This is where the warning is generated.

1525 abs(pdata->eq_cfg[i].rate - fs) < best_val) { 1526 best = i; 1527 best_val = abs(pdata->eq_cfg[i].rate - fs); 1528 } 1529 }

regards, dan carpenter