* [PATCH] ALSA: mips: avoid potential uninitialized variable use
@ 2017-01-16 11:04 Arnd Bergmann
2017-01-16 12:28 ` Takashi Iwai
0 siblings, 1 reply; 4+ messages in thread
From: Arnd Bergmann @ 2017-01-16 11:04 UTC (permalink / raw)
To: Jaroslav Kysela, Takashi Iwai
Cc: linux-mips, Arnd Bergmann, alsa-devel, linux-kernel
MIPS allmodconfig results in this warning:
sound/mips/hal2.c: In function 'hal2_gain_get':
sound/mips/hal2.c:224:35: error: 'r' may be used uninitialized in this function [-Werror=maybe-uninitialized]
sound/mips/hal2.c:223:35: error: 'l' may be used uninitialized in this function [-Werror=maybe-uninitialized]
sound/mips/hal2.c: In function 'hal2_gain_put':
sound/mips/hal2.c:260:13: error: 'new' may be used uninitialized in this function [-Werror=maybe-uninitialized]
sound/mips/hal2.c:260:13: error: 'old' may be used uninitialized in this function [-Werror=maybe-uninitialized]
It's easy enough to avoid by adding a 'default' clause to the switch
statements here. I assume that in practice no other case can happen,
but adding a default puts us on the safe side and shuts up the warnings.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
sound/mips/hal2.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/sound/mips/hal2.c b/sound/mips/hal2.c
index ede449f0b50d..0af4f7a9b3e7 100644
--- a/sound/mips/hal2.c
+++ b/sound/mips/hal2.c
@@ -219,6 +219,9 @@ static int hal2_gain_get(struct snd_kcontrol *kcontrol,
l = (tmp >> H2I_C2_L_GAIN_SHIFT) & 15;
r = (tmp >> H2I_C2_R_GAIN_SHIFT) & 15;
break;
+ default:
+ l = 0;
+ r = 0;
}
ucontrol->value.integer.value[0] = l;
ucontrol->value.integer.value[1] = r;
@@ -256,6 +259,9 @@ static int hal2_gain_put(struct snd_kcontrol *kcontrol,
new |= (r << H2I_C2_R_GAIN_SHIFT);
hal2_i_write32(hal2, H2I_ADC_C2, new);
break;
+ default:
+ new = 0;
+ old = 0;
}
return old != new;
}
--
2.9.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] ALSA: mips: avoid potential uninitialized variable use
@ 2017-01-16 12:28 ` Takashi Iwai
0 siblings, 0 replies; 4+ messages in thread
From: Takashi Iwai @ 2017-01-16 12:28 UTC (permalink / raw)
To: Arnd Bergmann; +Cc: Jaroslav Kysela, alsa-devel, linux-mips, linux-kernel
On Mon, 16 Jan 2017 12:04:56 +0100,
Arnd Bergmann wrote:
>
> MIPS allmodconfig results in this warning:
>
> sound/mips/hal2.c: In function 'hal2_gain_get':
> sound/mips/hal2.c:224:35: error: 'r' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> sound/mips/hal2.c:223:35: error: 'l' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> sound/mips/hal2.c: In function 'hal2_gain_put':
> sound/mips/hal2.c:260:13: error: 'new' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> sound/mips/hal2.c:260:13: error: 'old' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>
> It's easy enough to avoid by adding a 'default' clause to the switch
> statements here. I assume that in practice no other case can happen,
> but adding a default puts us on the safe side and shuts up the warnings.
Well, these cases are logical errors that must not happen, so
returning an error would be a "safer", IMO.
thanks,
Takashi
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> sound/mips/hal2.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/sound/mips/hal2.c b/sound/mips/hal2.c
> index ede449f0b50d..0af4f7a9b3e7 100644
> --- a/sound/mips/hal2.c
> +++ b/sound/mips/hal2.c
> @@ -219,6 +219,9 @@ static int hal2_gain_get(struct snd_kcontrol *kcontrol,
> l = (tmp >> H2I_C2_L_GAIN_SHIFT) & 15;
> r = (tmp >> H2I_C2_R_GAIN_SHIFT) & 15;
> break;
> + default:
> + l = 0;
> + r = 0;
> }
> ucontrol->value.integer.value[0] = l;
> ucontrol->value.integer.value[1] = r;
> @@ -256,6 +259,9 @@ static int hal2_gain_put(struct snd_kcontrol *kcontrol,
> new |= (r << H2I_C2_R_GAIN_SHIFT);
> hal2_i_write32(hal2, H2I_ADC_C2, new);
> break;
> + default:
> + new = 0;
> + old = 0;
> }
> return old != new;
> }
> --
> 2.9.0
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] ALSA: mips: avoid potential uninitialized variable use
@ 2017-01-16 12:28 ` Takashi Iwai
0 siblings, 0 replies; 4+ messages in thread
From: Takashi Iwai @ 2017-01-16 12:28 UTC (permalink / raw)
To: Arnd Bergmann; +Cc: Jaroslav Kysela, alsa-devel, linux-mips, linux-kernel
On Mon, 16 Jan 2017 12:04:56 +0100,
Arnd Bergmann wrote:
>
> MIPS allmodconfig results in this warning:
>
> sound/mips/hal2.c: In function 'hal2_gain_get':
> sound/mips/hal2.c:224:35: error: 'r' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> sound/mips/hal2.c:223:35: error: 'l' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> sound/mips/hal2.c: In function 'hal2_gain_put':
> sound/mips/hal2.c:260:13: error: 'new' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> sound/mips/hal2.c:260:13: error: 'old' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>
> It's easy enough to avoid by adding a 'default' clause to the switch
> statements here. I assume that in practice no other case can happen,
> but adding a default puts us on the safe side and shuts up the warnings.
Well, these cases are logical errors that must not happen, so
returning an error would be a "safer", IMO.
thanks,
Takashi
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> sound/mips/hal2.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/sound/mips/hal2.c b/sound/mips/hal2.c
> index ede449f0b50d..0af4f7a9b3e7 100644
> --- a/sound/mips/hal2.c
> +++ b/sound/mips/hal2.c
> @@ -219,6 +219,9 @@ static int hal2_gain_get(struct snd_kcontrol *kcontrol,
> l = (tmp >> H2I_C2_L_GAIN_SHIFT) & 15;
> r = (tmp >> H2I_C2_R_GAIN_SHIFT) & 15;
> break;
> + default:
> + l = 0;
> + r = 0;
> }
> ucontrol->value.integer.value[0] = l;
> ucontrol->value.integer.value[1] = r;
> @@ -256,6 +259,9 @@ static int hal2_gain_put(struct snd_kcontrol *kcontrol,
> new |= (r << H2I_C2_R_GAIN_SHIFT);
> hal2_i_write32(hal2, H2I_ADC_C2, new);
> break;
> + default:
> + new = 0;
> + old = 0;
> }
> return old != new;
> }
> --
> 2.9.0
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] ALSA: mips: avoid potential uninitialized variable use
2017-01-16 12:28 ` Takashi Iwai
(?)
@ 2017-01-16 13:26 ` Arnd Bergmann
-1 siblings, 0 replies; 4+ messages in thread
From: Arnd Bergmann @ 2017-01-16 13:26 UTC (permalink / raw)
To: Takashi Iwai
Cc: Jaroslav Kysela, alsa-devel, linux-mips, Linux Kernel Mailing List
On Mon, Jan 16, 2017 at 1:28 PM, Takashi Iwai <tiwai@suse.de> wrote:
> On Mon, 16 Jan 2017 12:04:56 +0100,
> Arnd Bergmann wrote:
>> It's easy enough to avoid by adding a 'default' clause to the switch
>> statements here. I assume that in practice no other case can happen,
>> but adding a default puts us on the safe side and shuts up the warnings.
>
> Well, these cases are logical errors that must not happen, so
> returning an error would be a "safer", IMO.
Agreed. I sent out a v2 now.
Arnd
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-01-16 13:26 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2017-01-16 11:04 [PATCH] ALSA: mips: avoid potential uninitialized variable use Arnd Bergmann
2017-01-16 12:28 ` Takashi Iwai
2017-01-16 12:28 ` Takashi Iwai
2017-01-16 13:26 ` Arnd Bergmann
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