Looks like this will not bring problem on patch_sigmatel.c, NULL and
valid kernel pointer are same for IS_ERR(), they will not make IS_ERR()
come true.
On 10/21/20 10:21 PM, Hui Wang wrote:
On 10/21/20 8:19 PM, Dan Carpenter wrote:
Hello Hui Wang,
The patch f4794c6064a8: "ALSA: hda - Don't register a cb func if it
is registered already" from Sep 30, 2020, leads to the following
static checker warning:
sound/pci/hda/patch_sigmatel.c:3075 stac92hd71bxx_fixup_hp_m4()
warn: 'jack' can also be NULL
sound/pci/hda/patch_sigmatel.c
3069 /* Enable VREF power saving on GPIO1 detect */
3070 snd_hda_codec_write_cache(codec, codec->core.afg, 0,
3071 AC_VERB_SET_GPIO_UNSOLICITED_RSP_MASK, 0x02);
3072 jack = snd_hda_jack_detect_enable_callback(codec,
codec->core.afg,
3073 stac_vref_event);
Originally snd_hda_jack_detect_enable_callback() would not return NULL
here.
3074 if (!IS_ERR(jack))
3075 jack->private_data = 0x02;
3076
3077 spec->gpio_mask |= 0x02;
But now we have this:
sound/pci/hda/hda_jack.c
301 struct hda_jack_callback *
302 snd_hda_jack_detect_enable_callback_mst(struct hda_codec
*codec, hda_nid_t nid,
303 int dev_id,
hda_jack_callback_fn func)
304 {
305 struct hda_jack_tbl *jack;
306 struct hda_jack_callback *callback = NULL;
307 int err;
308
309 jack = snd_hda_jack_tbl_new(codec, nid, dev_id);
310 if (!jack)
311 return ERR_PTR(-ENOMEM);
312 if (func && !func_is_already_in_callback_list(jack,
func)) {
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
We only allocate callback if there isn't one already.
Yes, indeed, this is a problem.
313 callback = kzalloc(sizeof(*callback),
GFP_KERNEL);
314 if (!callback)
315 return ERR_PTR(-ENOMEM);
316 callback->func = func;
317 callback->nid = jack->nid;
318 callback->dev_id = jack->dev_id;
319 callback->next = jack->callback;
320 jack->callback = callback;
321 }
322
323 if (jack->jack_detect)
324 return callback; /* already registered */
^^^^^^^^^^^^^^^
So presumably this should be jack->callback
Looks like it is also not correct to return the jack->callback. Need
to take some time to write a fix for it.
Thanks for reporting the issue.
325 jack->jack_detect = 1;
326 if (codec->jackpoll_interval > 0)
327 return callback; /* No unsol if we're
polling instead */
^^^^^^^^^^^^^^^^
328 err = snd_hda_codec_write_cache(codec, nid, 0,
329 AC_VERB_SET_UNSOLICITED_ENABLE,
330 AC_USRSP_EN |
jack->tag);
331 if (err < 0)
332 return ERR_PTR(err);
333 return callback;
^^^^^^^^^^^^^^^^
And these as well.
334 }
regards,
dan carpenter
