Messages in this thread |  | | Date | Wed, 03 Dec 2025 13:54:28 +0100 | | From | Takashi Iwai <> | | Subject | Re: [PATCH] ALSA: usb-audio: Initialize status1 to fix uninitialized symbol errors |
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On Wed, 03 Dec 2025 13:01:48 +0100, HariKrishna Sagala wrote: > > On Wed, 3 Dec 2025, Takashi Iwai wrote: > > > On Wed, 03 Dec 2025 12:22:27 +0100, > > HariKrishna Sagala wrote: > > > > > > On Wed, 3 Dec 2025, Takashi Iwai wrote: > > > > > > > On Wed, 03 Dec 2025 12:01:35 +0100, > > > > HariKrishna Sagala wrote: > > > > > > > > > > On Wed, 3 Dec 2025, Takashi Iwai wrote: > > > > > > > > > > > On Wed, 03 Dec 2025 09:33:20 +0100, > > > > > > hariconscious@gmail.com wrote: > > > > > > > > > > > > > > From: HariKrishna Sagala <hariconscious@gmail.com> > > > > > > > > > > > > > > Initialize 'status1' with a default value to resolve the static analysis > > > > > > > smatch reported error "uninitialized symbol 'status1'". > > > > > > > The 'status1' variable is used to create a buff using "kmemdup". > > > > > > > So, ensure to initialize the value before it is read. > > > > > > > > > > > > > > Signed-off-by: HariKrishna Sagala <hariconscious@gmail.com> > > > > > > > --- > > > > > > > This patch fixes the below smatch reported errors. > > > > > > > sound/usb/mixer_quirks.c:2462 snd_rme_rate_get() error: uninitialized symbol 'status1'. > > > > > > > sound/usb/mixer_quirks.c:2467 snd_rme_rate_get() error: uninitialized symbol 'status1'. > > > > > > > sound/usb/mixer_quirks.c:2472 snd_rme_rate_get() error: uninitialized symbol 'status1'. > > > > > > > sound/usb/mixer_quirks.c:2495 snd_rme_sync_state_get() error: uninitialized symbol 'status1'. > > > > > > > sound/usb/mixer_quirks.c:2501 snd_rme_sync_state_get() error: uninitialized symbol 'status1'. > > > > > > > sound/usb/mixer_quirks.c:2522 snd_rme_spdif_if_get() error: uninitialized symbol 'status1'. > > > > > > > sound/usb/mixer_quirks.c:2535 snd_rme_spdif_format_get() error: uninitialized symbol 'status1'. > > > > > > > sound/usb/mixer_quirks.c:2548 snd_rme_sync_source_get() error: uninitialized symbol 'status1'. > > > > > > > > > > > > > > The below is the flow of 'status1' it is used before initialization. > > > > > > > > > > > > > > snd_rme_rate_get -> status1 is uninitialized and passed > > > > > > > snd_rme_get_status1 -> passed as is > > > > > > > snd_rme_read_value -> passed as is > > > > > > > snd_usb_ctl_msg -> created buf from status1 using kmemdup > > > > > > > usb_control_msg -> sent buf for reading/writing > > > > > > > > > > > > > > Description of "usb_control_msg", states as > > > > > > > " * @data: pointer to the data to send" > > > > > > > > > > > > > > Later from Usb control request, dst buf is copied to src buf but usb > > > > > > > control msg request is made before initialization. > > > > > > > > > > > > > > Thank you. > > > > > > > > > > > > > > sound/usb/mixer_quirks.c | 10 +++++----- > > > > > > > 1 file changed, 5 insertions(+), 5 deletions(-) > > > > > > > > > > > > > > diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c > > > > > > > index 828af3095b86..06903c5de087 100644 > > > > > > > --- a/sound/usb/mixer_quirks.c > > > > > > > +++ b/sound/usb/mixer_quirks.c > > > > > > > @@ -2449,7 +2449,7 @@ static int snd_rme_get_status1(struct snd_kcontrol *kcontrol, > > > > > > > static int snd_rme_rate_get(struct snd_kcontrol *kcontrol, > > > > > > > struct snd_ctl_elem_value *ucontrol) > > > > > > > { > > > > > > > - u32 status1; > > > > > > > + u32 status1 = 0; > > > > > > > u32 rate = 0; > > > > > > > int idx; > > > > > > > int err; > > > > > > > @@ -2483,7 +2483,7 @@ static int snd_rme_rate_get(struct snd_kcontrol *kcontrol, > > > > > > > static int snd_rme_sync_state_get(struct snd_kcontrol *kcontrol, > > > > > > > struct snd_ctl_elem_value *ucontrol) > > > > > > > { > > > > > > > - u32 status1; > > > > > > > + u32 status1 = 0; > > > > > > > int idx = SND_RME_CLOCK_NOLOCK; > > > > > > > int err; > > > > > > > > > > > > > > @@ -2513,7 +2513,7 @@ static int snd_rme_sync_state_get(struct snd_kcontrol *kcontrol, > > > > > > > static int snd_rme_spdif_if_get(struct snd_kcontrol *kcontrol, > > > > > > > struct snd_ctl_elem_value *ucontrol) > > > > > > > { > > > > > > > - u32 status1; > > > > > > > + u32 status1 = 0; > > > > > > > int err; > > > > > > > > > > > > > > err = snd_rme_get_status1(kcontrol, &status1); > > > > > > > @@ -2526,7 +2526,7 @@ static int snd_rme_spdif_if_get(struct snd_kcontrol *kcontrol, > > > > > > > static int snd_rme_spdif_format_get(struct snd_kcontrol *kcontrol, > > > > > > > struct snd_ctl_elem_value *ucontrol) > > > > > > > { > > > > > > > - u32 status1; > > > > > > > + u32 status1 = 0; > > > > > > > int err; > > > > > > > > > > > > > > err = snd_rme_get_status1(kcontrol, &status1); > > > > > > > @@ -2539,7 +2539,7 @@ static int snd_rme_spdif_format_get(struct snd_kcontrol *kcontrol, > > > > > > > static int snd_rme_sync_source_get(struct snd_kcontrol *kcontrol, > > > > > > > struct snd_ctl_elem_value *ucontrol) > > > > > > > { > > > > > > > - u32 status1; > > > > > > > + u32 status1 = 0; > > > > > > > int err; > > > > > > > > > > > > > > err = snd_rme_get_status1(kcontrol, &status1); > > > > > > > > > > > > > > > > > > > The warning itself is rather dubious. But it'd certainly give a safer > > > > > > feeling to cover the uninitialized variables, so it would still make > > > > > > some sense. > > > > > > > > > > > > But, the code change can be improved. e.g. initialize the value in > > > > > > the callee side, instead of callers; then it'll reduce all changes to > > > > > > a one-liner. > > > > > > > > > > > > At the next time, please look at the patterns you changed more closely > > > > > > and think again whether it's the best change or not before submission. > > > > > > On the second look, often you see things from a different perspective > > > > > > :) > > > > > > > > > > > > > > > > > > thanks, > > > > > > > > > > > > Takashi > > > > > > > > > > > > > > > > Hi Takashi, > > > > > > > > > > Thank you for the feedback and complement. > > > > > Yes, will check the pattern and avoid this going forward. > > > > > As all the functions call "snd_rme_get_status1", > > > > > initialized here but smatch didn't silence them. > > > > > > > > > > I prefer initializing a variable in caller side as it owns > > > > > and aware of initialized value sent. > > > > > > > > > > Sorry, if I had misunderstood your suggestion. > > > > > > > > Well, you seem driven too much by smatch. Just look at your patch > > > > again. > > > > > > > > You're repeating the same initializations and passing to the same > > > > function. And those are the only callers of snd_rme_get_status1(). > > > > So, instead of initializing in the caller side, initialize the value > > > > in snd_rme_get_status1(). Then the whole your changes will be > > > > oneliner like below. > > > > > > > > > > > > Takashi > > > > > > > > --- a/sound/usb/mixer_quirks.c > > > > +++ b/sound/usb/mixer_quirks.c > > > > @@ -2548,6 +2548,7 @@ static int snd_rme_get_status1(struct snd_kcontrol *kcontrol, > > > > CLASS(snd_usb_lock, pm)(chip); > > > > if (pm.err < 0) > > > > return pm.err; > > > > + *status1 = 0; > > > > return snd_rme_read_value(chip, SND_RME_GET_STATUS1, status1); > > > > } > > > > > > > > > > > > > > Hi Takashi, > > > > > > Yes, tried that before, smatch didn't silence them. > > > > Then it's an obvious failure of smatch. > > > > Or you might set *status1 = 0 at the beginning of > > snd_rme_get_status1() although it makes little sense. > > > > > If it is worth having this change though they are not silenced, > > > will raise v2 otherwise will drop this patch. > > > > If the smatch still complains, it's not worth. > > > > > > Takashi > > > > Hi Takashi, > > This is the change I tried but smatch didn't silence them. > > diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c > index 828af3095b86..10354576d325 100644 > --- a/sound/usb/mixer_quirks.c > +++ b/sound/usb/mixer_quirks.c > @@ -2443,6 +2443,7 @@ static int snd_rme_get_status1(struct snd_kcontrol > *kcontrol, > CLASS(snd_usb_lock, pm)(chip); > if (pm.err < 0) > return pm.err; > + *status1 = 0; > return snd_rme_read_value(chip, SND_RME_GET_STATUS1, status1); > } > > Below are reported with the change, as seen they are not silenced. > > sound/usb/mixer_quirks.c:2463 snd_rme_rate_get() error: uninitialized > symbol 'status1'. > sound/usb/mixer_quirks.c:2468 snd_rme_rate_get() error: uninitialized > symbol 'status1'. > sound/usb/mixer_quirks.c:2473 snd_rme_rate_get() error: uninitialized > symbol 'status1'. > sound/usb/mixer_quirks.c:2496 snd_rme_sync_state_get() error: > uninitialized symbol 'status1'. > sound/usb/mixer_quirks.c:2502 snd_rme_sync_state_get() error: > uninitialized symbol 'status1'. > sound/usb/mixer_quirks.c:2523 snd_rme_spdif_if_get() error: uninitialized > symbol 'status1'. > sound/usb/mixer_quirks.c:2536 snd_rme_spdif_format_get() error: > uninitialized symbol 'status1'. > sound/usb/mixer_quirks.c:2549 snd_rme_sync_source_get() error: > uninitialized symbol 'status1'. > sound/usb/mixer_quirks.c:4137 snd_djm_controls_info() warn: potential > spectre issue 'ctl->options' [r] (local cap)
As mentioned, try to put *status1=0 line before CLASS() call in the above. If this still doesn't help, it's a bug of smatch, and we should ignore it.
Takashi
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