[PATCH 1/2] ASoC: cs35l32: avoid uninitialized variable access

[PATCH 1/2] ASoC: cs35l32: avoid uninitialized variable access

[Arnd Bergmann]

gcc warns about the possibilty of accessing a property read from
devicetree in cs35l32_i2c_probe() when it has not been initialized
because CONFIG_OF is disabled:

sound/soc/codecs/cs35l32.c: In function 'cs35l32_i2c_probe':
sound/soc/codecs/cs35l32.c:278:2: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]

The code is actually correct because it checks the dev->of_node
variable first and we know this is NULL here, but by adding a
check for IS_ENABLED(CONFIG_OF), we can let the compiler know
as well, and also generate smaller object code.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 sound/soc/codecs/cs35l32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/codecs/cs35l32.c b/sound/soc/codecs/cs35l32.c
index 44c30fe3e315..52ffaa8eb02b 100644
--- a/sound/soc/codecs/cs35l32.c
+++ b/sound/soc/codecs/cs35l32.c
@@ -372,7 +372,7 @@ static int cs35l32_i2c_probe(struct i2c_client *i2c_client,
 			dev_err(&i2c_client->dev, "could not allocate pdata\n");
 			return -ENOMEM;
 		}
-		if (i2c_client->dev.of_node) {
+		if (IS_ENABLED(CONFIG_OF) && i2c_client->dev.of_node) {
 			ret = cs35l32_handle_of_data(i2c_client,
 						     &cs35l32->pdata);
 			if (ret != 0)
-- 
2.7.0

[PATCH 1/2] ASoC: cs35l32: avoid uninitialized variable access

[Arnd Bergmann]

gcc warns about the possibilty of accessing a property read from
devicetree in cs35l32_i2c_probe() when it has not been initialized
because CONFIG_OF is disabled:

sound/soc/codecs/cs35l32.c: In function 'cs35l32_i2c_probe':
sound/soc/codecs/cs35l32.c:278:2: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]

The code is actually correct because it checks the dev->of_node
variable first and we know this is NULL here, but by adding a
check for IS_ENABLED(CONFIG_OF), we can let the compiler know
as well, and also generate smaller object code.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 sound/soc/codecs/cs35l32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/codecs/cs35l32.c b/sound/soc/codecs/cs35l32.c
index 44c30fe3e315..52ffaa8eb02b 100644
--- a/sound/soc/codecs/cs35l32.c
+++ b/sound/soc/codecs/cs35l32.c
@@ -372,7 +372,7 @@ static int cs35l32_i2c_probe(struct i2c_client *i2c_client,
 			dev_err(&i2c_client->dev, "could not allocate pdata\n");
 			return -ENOMEM;
 		}
-		if (i2c_client->dev.of_node) {
+		if (IS_ENABLED(CONFIG_OF) && i2c_client->dev.of_node) {
 			ret = cs35l32_handle_of_data(i2c_client,
 						     &cs35l32->pdata);
 			if (ret != 0)
-- 
2.7.0

[PATCH 2/2] ASoC: s3c24xx: use const snd_soc_component_driver pointer

[Arnd Bergmann]

An older patch to convert the API in the s3c i2s driver
ended up passing a const pointer into a function that takes
a non-const pointer, so we now get a warning:

sound/soc/samsung/s3c2412-i2s.c: In function 's3c2412_iis_dev_probe':
sound/soc/samsung/s3c2412-i2s.c:172:9: error: passing argument 3 of 's3c_i2sv2_register_component' discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]

However, the s3c_i2sv2_register_component() function again
passes the pointer into another function taking a const, so
we just need to change its prototype.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: eca3b01d0885 ("ASoC: switch over to use snd_soc_register_component() on s3c i2s")
---
 sound/soc/samsung/s3c-i2s-v2.c | 2 +-
 sound/soc/samsung/s3c-i2s-v2.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/soc/samsung/s3c-i2s-v2.c b/sound/soc/samsung/s3c-i2s-v2.c
index df65c5b494b1..b6ab3fc5789e 100644
--- a/sound/soc/samsung/s3c-i2s-v2.c
+++ b/sound/soc/samsung/s3c-i2s-v2.c
@@ -709,7 +709,7 @@ static int s3c2412_i2s_resume(struct snd_soc_dai *dai)
 #endif
 
 int s3c_i2sv2_register_component(struct device *dev, int id,
-			   struct snd_soc_component_driver *cmp_drv,
+			   const struct snd_soc_component_driver *cmp_drv,
 			   struct snd_soc_dai_driver *dai_drv)
 {
 	struct snd_soc_dai_ops *ops = (struct snd_soc_dai_ops *)dai_drv->ops;
diff --git a/sound/soc/samsung/s3c-i2s-v2.h b/sound/soc/samsung/s3c-i2s-v2.h
index 90abab364b49..d0684145ed1f 100644
--- a/sound/soc/samsung/s3c-i2s-v2.h
+++ b/sound/soc/samsung/s3c-i2s-v2.h
@@ -101,7 +101,7 @@ extern int s3c_i2sv2_probe(struct snd_soc_dai *dai,
  * soc core.
  */
 extern int s3c_i2sv2_register_component(struct device *dev, int id,
-					struct snd_soc_component_driver *cmp_drv,
+					const struct snd_soc_component_driver *cmp_drv,
 					struct snd_soc_dai_driver *dai_drv);
 
 #endif /* __SND_SOC_S3C24XX_S3C_I2SV2_I2S_H */
-- 
2.7.0

[PATCH 2/2] ASoC: s3c24xx: use const snd_soc_component_driver pointer

[Arnd Bergmann]

An older patch to convert the API in the s3c i2s driver
ended up passing a const pointer into a function that takes
a non-const pointer, so we now get a warning:

sound/soc/samsung/s3c2412-i2s.c: In function 's3c2412_iis_dev_probe':
sound/soc/samsung/s3c2412-i2s.c:172:9: error: passing argument 3 of 's3c_i2sv2_register_component' discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]

However, the s3c_i2sv2_register_component() function again
passes the pointer into another function taking a const, so
we just need to change its prototype.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: eca3b01d0885 ("ASoC: switch over to use snd_soc_register_component() on s3c i2s")
---
 sound/soc/samsung/s3c-i2s-v2.c | 2 +-
 sound/soc/samsung/s3c-i2s-v2.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/soc/samsung/s3c-i2s-v2.c b/sound/soc/samsung/s3c-i2s-v2.c
index df65c5b494b1..b6ab3fc5789e 100644
--- a/sound/soc/samsung/s3c-i2s-v2.c
+++ b/sound/soc/samsung/s3c-i2s-v2.c
@@ -709,7 +709,7 @@ static int s3c2412_i2s_resume(struct snd_soc_dai *dai)
 #endif
 
 int s3c_i2sv2_register_component(struct device *dev, int id,
-			   struct snd_soc_component_driver *cmp_drv,
+			   const struct snd_soc_component_driver *cmp_drv,
 			   struct snd_soc_dai_driver *dai_drv)
 {
 	struct snd_soc_dai_ops *ops = (struct snd_soc_dai_ops *)dai_drv->ops;
diff --git a/sound/soc/samsung/s3c-i2s-v2.h b/sound/soc/samsung/s3c-i2s-v2.h
index 90abab364b49..d0684145ed1f 100644
--- a/sound/soc/samsung/s3c-i2s-v2.h
+++ b/sound/soc/samsung/s3c-i2s-v2.h
@@ -101,7 +101,7 @@ extern int s3c_i2sv2_probe(struct snd_soc_dai *dai,
  * soc core.
  */
 extern int s3c_i2sv2_register_component(struct device *dev, int id,
-					struct snd_soc_component_driver *cmp_drv,
+					const struct snd_soc_component_driver *cmp_drv,
 					struct snd_soc_dai_driver *dai_drv);
 
 #endif /* __SND_SOC_S3C24XX_S3C_I2SV2_I2S_H */
-- 
2.7.0

[PATCH 2/2] ASoC: s3c24xx: use const snd_soc_component_driver pointer

[Arnd Bergmann]

An older patch to convert the API in the s3c i2s driver
ended up passing a const pointer into a function that takes
a non-const pointer, so we now get a warning:

sound/soc/samsung/s3c2412-i2s.c: In function 's3c2412_iis_dev_probe':
sound/soc/samsung/s3c2412-i2s.c:172:9: error: passing argument 3 of 's3c_i2sv2_register_component' discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]

However, the s3c_i2sv2_register_component() function again
passes the pointer into another function taking a const, so
we just need to change its prototype.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: eca3b01d0885 ("ASoC: switch over to use snd_soc_register_component() on s3c i2s")
---
 sound/soc/samsung/s3c-i2s-v2.c | 2 +-
 sound/soc/samsung/s3c-i2s-v2.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/soc/samsung/s3c-i2s-v2.c b/sound/soc/samsung/s3c-i2s-v2.c
index df65c5b494b1..b6ab3fc5789e 100644
--- a/sound/soc/samsung/s3c-i2s-v2.c
+++ b/sound/soc/samsung/s3c-i2s-v2.c
@@ -709,7 +709,7 @@ static int s3c2412_i2s_resume(struct snd_soc_dai *dai)
 #endif
 
 int s3c_i2sv2_register_component(struct device *dev, int id,
-			   struct snd_soc_component_driver *cmp_drv,
+			   const struct snd_soc_component_driver *cmp_drv,
 			   struct snd_soc_dai_driver *dai_drv)
 {
 	struct snd_soc_dai_ops *ops = (struct snd_soc_dai_ops *)dai_drv->ops;
diff --git a/sound/soc/samsung/s3c-i2s-v2.h b/sound/soc/samsung/s3c-i2s-v2.h
index 90abab364b49..d0684145ed1f 100644
--- a/sound/soc/samsung/s3c-i2s-v2.h
+++ b/sound/soc/samsung/s3c-i2s-v2.h
@@ -101,7 +101,7 @@ extern int s3c_i2sv2_probe(struct snd_soc_dai *dai,
  * soc core.
  */
 extern int s3c_i2sv2_register_component(struct device *dev, int id,
-					struct snd_soc_component_driver *cmp_drv,
+					const struct snd_soc_component_driver *cmp_drv,
 					struct snd_soc_dai_driver *dai_drv);
 
 #endif /* __SND_SOC_S3C24XX_S3C_I2SV2_I2S_H */
-- 
2.7.0

Re: [PATCH 2/2] ASoC: s3c24xx: use const snd_soc_component_driver pointer

[Krzysztof Kozlowski]

On 26.01.2016 02:07, Arnd Bergmann wrote:
> An older patch to convert the API in the s3c i2s driver
> ended up passing a const pointer into a function that takes
> a non-const pointer, so we now get a warning:
> 
> sound/soc/samsung/s3c2412-i2s.c: In function 's3c2412_iis_dev_probe':
> sound/soc/samsung/s3c2412-i2s.c:172:9: error: passing argument 3 of 's3c_i2sv2_register_component' discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
> 
> However, the s3c_i2sv2_register_component() function again
> passes the pointer into another function taking a const, so
> we just need to change its prototype.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Fixes: eca3b01d0885 ("ASoC: switch over to use snd_soc_register_component() on s3c i2s")
> ---
>  sound/soc/samsung/s3c-i2s-v2.c | 2 +-
>  sound/soc/samsung/s3c-i2s-v2.h | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 

Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>

Best regards,
Krzysztof

[PATCH 2/2] ASoC: s3c24xx: use const snd_soc_component_driver pointer

[Krzysztof Kozlowski]

On 26.01.2016 02:07, Arnd Bergmann wrote:
> An older patch to convert the API in the s3c i2s driver
> ended up passing a const pointer into a function that takes
> a non-const pointer, so we now get a warning:
> 
> sound/soc/samsung/s3c2412-i2s.c: In function 's3c2412_iis_dev_probe':
> sound/soc/samsung/s3c2412-i2s.c:172:9: error: passing argument 3 of 's3c_i2sv2_register_component' discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
> 
> However, the s3c_i2sv2_register_component() function again
> passes the pointer into another function taking a const, so
> we just need to change its prototype.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Fixes: eca3b01d0885 ("ASoC: switch over to use snd_soc_register_component() on s3c i2s")
> ---
>  sound/soc/samsung/s3c-i2s-v2.c | 2 +-
>  sound/soc/samsung/s3c-i2s-v2.h | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 

Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>

Best regards,
Krzysztof

Applied "ASoC: s3c24xx: use const snd_soc_component_driver pointer" to the asoc tree

[Mark Brown]

The patch

   ASoC: s3c24xx: use const snd_soc_component_driver pointer

has been applied to the asoc tree at

   git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From ba4bc32eaa39ba7687f0958ae90eec94da613b46 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Mon, 25 Jan 2016 18:07:33 +0100
Subject: [PATCH] ASoC: s3c24xx: use const snd_soc_component_driver pointer

An older patch to convert the API in the s3c i2s driver
ended up passing a const pointer into a function that takes
a non-const pointer, so we now get a warning:

sound/soc/samsung/s3c2412-i2s.c: In function 's3c2412_iis_dev_probe':
sound/soc/samsung/s3c2412-i2s.c:172:9: error: passing argument 3 of 's3c_i2sv2_register_component' discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]

However, the s3c_i2sv2_register_component() function again
passes the pointer into another function taking a const, so
we just need to change its prototype.

Fixes: eca3b01d0885 ("ASoC: switch over to use snd_soc_register_component() on s3c i2s")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 sound/soc/samsung/s3c-i2s-v2.c | 2 +-
 sound/soc/samsung/s3c-i2s-v2.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/soc/samsung/s3c-i2s-v2.c b/sound/soc/samsung/s3c-i2s-v2.c
index df65c5b494b1..b6ab3fc5789e 100644
--- a/sound/soc/samsung/s3c-i2s-v2.c
+++ b/sound/soc/samsung/s3c-i2s-v2.c
@@ -709,7 +709,7 @@ static int s3c2412_i2s_resume(struct snd_soc_dai *dai)
 #endif
 
 int s3c_i2sv2_register_component(struct device *dev, int id,
-			   struct snd_soc_component_driver *cmp_drv,
+			   const struct snd_soc_component_driver *cmp_drv,
 			   struct snd_soc_dai_driver *dai_drv)
 {
 	struct snd_soc_dai_ops *ops = (struct snd_soc_dai_ops *)dai_drv->ops;
diff --git a/sound/soc/samsung/s3c-i2s-v2.h b/sound/soc/samsung/s3c-i2s-v2.h
index 90abab364b49..d0684145ed1f 100644
--- a/sound/soc/samsung/s3c-i2s-v2.h
+++ b/sound/soc/samsung/s3c-i2s-v2.h
@@ -101,7 +101,7 @@ extern int s3c_i2sv2_probe(struct snd_soc_dai *dai,
  * soc core.
  */
 extern int s3c_i2sv2_register_component(struct device *dev, int id,
-					struct snd_soc_component_driver *cmp_drv,
+					const struct snd_soc_component_driver *cmp_drv,
 					struct snd_soc_dai_driver *dai_drv);
 
 #endif /* __SND_SOC_S3C24XX_S3C_I2SV2_I2S_H */
-- 
2.7.0.rc3

Re: [PATCH 1/2] ASoC: cs35l32: avoid uninitialized variable access

[Austin, Brian]

On Jan 25, 2016, at 11:07 AM, Arnd Bergmann <arnd@arndb.de<mailto:arnd@arndb.de>> wrote:

gcc warns about the possibilty of accessing a property read from
devicetree in cs35l32_i2c_probe() when it has not been initialized
because CONFIG_OF is disabled:

sound/soc/codecs/cs35l32.c: In function 'cs35l32_i2c_probe':
sound/soc/codecs/cs35l32.c:278:2: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]

The code is actually correct because it checks the dev->of_node
variable first and we know this is NULL here, but by adding a
check for IS_ENABLED(CONFIG_OF), we can let the compiler know
as well, and also generate smaller object code.

Signed-off-by: Arnd Bergmann <arnd@arndb.de<mailto:arnd@arndb.de>>
---
sound/soc/codecs/cs35l32.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Thanks,

Acked-by: Brian Austin <brian.austin@cirrus.com<mailto:brian.austin@cirrus.com>>

Re: [PATCH 1/2] ASoC: cs35l32: avoid uninitialized variable access

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 295 bytes --]

On Mon, Jan 25, 2016 at 06:07:32PM +0100, Arnd Bergmann wrote:

> -		if (i2c_client->dev.of_node) {
> +		if (IS_ENABLED(CONFIG_OF) && i2c_client->dev.of_node) {

This feels it's going to be happening a lot and we should probably have
a dev_has_of_node() helper that does the IS_ENABLED() check.

[-- Attachment #2: signature.asc --]
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[PATCH 1/2] ASoC: cs35l32: avoid uninitialized variable access

[Mark Brown]

On Mon, Jan 25, 2016 at 06:07:32PM +0100, Arnd Bergmann wrote:

> -		if (i2c_client->dev.of_node) {
> +		if (IS_ENABLED(CONFIG_OF) && i2c_client->dev.of_node) {

This feels it's going to be happening a lot and we should probably have
a dev_has_of_node() helper that does the IS_ENABLED() check.
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Re: [PATCH 1/2] ASoC: cs35l32: avoid uninitialized variable access

[Russell King - ARM Linux]

On Mon, Jan 25, 2016 at 06:07:32PM +0100, Arnd Bergmann wrote:
> gcc warns about the possibilty of accessing a property read from
> devicetree in cs35l32_i2c_probe() when it has not been initialized
> because CONFIG_OF is disabled:
> 
> sound/soc/codecs/cs35l32.c: In function 'cs35l32_i2c_probe':
> sound/soc/codecs/cs35l32.c:278:2: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]
> 
> The code is actually correct because it checks the dev->of_node
> variable first and we know this is NULL here, but by adding a
> check for IS_ENABLED(CONFIG_OF), we can let the compiler know
> as well, and also generate smaller object code.

No, the code is buggy, and the compiler is very correct in warning about
it.

The code there is:

        of_property_read_u32(np, "cirrus,boost-manager", &val);
        switch (val) {

of_property_read_u32() is aliased to of_property_read_u32_array() via:

static inline int of_property_read_u32(const struct device_node *np,
                                       const char *propname,
                                       u32 *out_value)
{
        return of_property_read_u32_array(np, propname, out_value, 1);
}

which does this:

int of_property_read_u32_array(const struct device_node *np,
                               const char *propname, u32 *out_values,
                               size_t sz)
{
        const __be32 *val = of_find_property_value_of_size(np, propname,
                                                (sz * sizeof(*out_values)));

        if (IS_ERR(val))
                return PTR_ERR(val);

        while (sz--)
                *out_values++ = be32_to_cpup(val++);
        return 0;
}

Note that 'out_values' is not written to if of_find_property_value_of_size()
returns an error.  Therefore, if cirrus,boost-manager is missing, the
resulting value of 'val' is left uninitialised.

-- 
RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

[PATCH 1/2] ASoC: cs35l32: avoid uninitialized variable access

[Russell King - ARM Linux]

On Mon, Jan 25, 2016 at 06:07:32PM +0100, Arnd Bergmann wrote:
> gcc warns about the possibilty of accessing a property read from
> devicetree in cs35l32_i2c_probe() when it has not been initialized
> because CONFIG_OF is disabled:
> 
> sound/soc/codecs/cs35l32.c: In function 'cs35l32_i2c_probe':
> sound/soc/codecs/cs35l32.c:278:2: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]
> 
> The code is actually correct because it checks the dev->of_node
> variable first and we know this is NULL here, but by adding a
> check for IS_ENABLED(CONFIG_OF), we can let the compiler know
> as well, and also generate smaller object code.

No, the code is buggy, and the compiler is very correct in warning about
it.

The code there is:

        of_property_read_u32(np, "cirrus,boost-manager", &val);
        switch (val) {

of_property_read_u32() is aliased to of_property_read_u32_array() via:

static inline int of_property_read_u32(const struct device_node *np,
                                       const char *propname,
                                       u32 *out_value)
{
        return of_property_read_u32_array(np, propname, out_value, 1);
}

which does this:

int of_property_read_u32_array(const struct device_node *np,
                               const char *propname, u32 *out_values,
                               size_t sz)
{
        const __be32 *val = of_find_property_value_of_size(np, propname,
                                                (sz * sizeof(*out_values)));

        if (IS_ERR(val))
                return PTR_ERR(val);

        while (sz--)
                *out_values++ = be32_to_cpup(val++);
        return 0;
}

Note that 'out_values' is not written to if of_find_property_value_of_size()
returns an error.  Therefore, if cirrus,boost-manager is missing, the
resulting value of 'val' is left uninitialised.

-- 
RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

Re: [PATCH 1/2] ASoC: cs35l32: avoid uninitialized variable access

[Arnd Bergmann]

On Saturday 05 March 2016, Russell King - ARM Linux wrote:
> On Mon, Jan 25, 2016 at 06:07:32PM +0100, Arnd Bergmann wrote:
> > gcc warns about the possibilty of accessing a property read from
> > devicetree in cs35l32_i2c_probe() when it has not been initialized
> > because CONFIG_OF is disabled:
> > 
> > sound/soc/codecs/cs35l32.c: In function 'cs35l32_i2c_probe':
> > sound/soc/codecs/cs35l32.c:278:2: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]
> > 
> > The code is actually correct because it checks the dev->of_node
> > variable first and we know this is NULL here, but by adding a
> > check for IS_ENABLED(CONFIG_OF), we can let the compiler know
> > as well, and also generate smaller object code.
> 
> No, the code is buggy, and the compiler is very correct in warning about
> it.

...
> 
> Note that 'out_values' is not written to if of_find_property_value_of_size()
> returns an error.  Therefore, if cirrus,boost-manager is missing, the
> resulting value of 'val' is left uninitialised.

You are right, this is an actual bug in the driver, and my patch just
hides it. Interestingly, this is not the case that the warning was about,
as we get the warning only when CONFIG_OF is disabled and the code
is correct (because dev->of_node is guaranteed to be NULL), but we
don't get the warning when CONFIG_OF is enabled and we can actually
run into the problem.

Fixing the driver to have correct error handling on the property
functions will make the warning go away and fix the bug you pointed
out, so we should definitely do that and drop my patch.

	Arnd

Re: [PATCH 1/2] ASoC: cs35l32: avoid uninitialized variable access

[Arnd Bergmann]

On Saturday 05 March 2016, Russell King - ARM Linux wrote:
> On Mon, Jan 25, 2016 at 06:07:32PM +0100, Arnd Bergmann wrote:
> > gcc warns about the possibilty of accessing a property read from
> > devicetree in cs35l32_i2c_probe() when it has not been initialized
> > because CONFIG_OF is disabled:
> > 
> > sound/soc/codecs/cs35l32.c: In function 'cs35l32_i2c_probe':
> > sound/soc/codecs/cs35l32.c:278:2: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]
> > 
> > The code is actually correct because it checks the dev->of_node
> > variable first and we know this is NULL here, but by adding a
> > check for IS_ENABLED(CONFIG_OF), we can let the compiler know
> > as well, and also generate smaller object code.
> 
> No, the code is buggy, and the compiler is very correct in warning about
> it.

...
> 
> Note that 'out_values' is not written to if of_find_property_value_of_size()
> returns an error.  Therefore, if cirrus,boost-manager is missing, the
> resulting value of 'val' is left uninitialised.

You are right, this is an actual bug in the driver, and my patch just
hides it. Interestingly, this is not the case that the warning was about,
as we get the warning only when CONFIG_OF is disabled and the code
is correct (because dev->of_node is guaranteed to be NULL), but we
don't get the warning when CONFIG_OF is enabled and we can actually
run into the problem.

Fixing the driver to have correct error handling on the property
functions will make the warning go away and fix the bug you pointed
out, so we should definitely do that and drop my patch.

	Arnd

[PATCH 1/2] ASoC: cs35l32: avoid uninitialized variable access

[Arnd Bergmann]

On Saturday 05 March 2016, Russell King - ARM Linux wrote:
> On Mon, Jan 25, 2016 at 06:07:32PM +0100, Arnd Bergmann wrote:
> > gcc warns about the possibilty of accessing a property read from
> > devicetree in cs35l32_i2c_probe() when it has not been initialized
> > because CONFIG_OF is disabled:
> > 
> > sound/soc/codecs/cs35l32.c: In function 'cs35l32_i2c_probe':
> > sound/soc/codecs/cs35l32.c:278:2: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]
> > 
> > The code is actually correct because it checks the dev->of_node
> > variable first and we know this is NULL here, but by adding a
> > check for IS_ENABLED(CONFIG_OF), we can let the compiler know
> > as well, and also generate smaller object code.
> 
> No, the code is buggy, and the compiler is very correct in warning about
> it.

...
> 
> Note that 'out_values' is not written to if of_find_property_value_of_size()
> returns an error.  Therefore, if cirrus,boost-manager is missing, the
> resulting value of 'val' is left uninitialised.

You are right, this is an actual bug in the driver, and my patch just
hides it. Interestingly, this is not the case that the warning was about,
as we get the warning only when CONFIG_OF is disabled and the code
is correct (because dev->of_node is guaranteed to be NULL), but we
don't get the warning when CONFIG_OF is enabled and we can actually
run into the problem.

Fixing the driver to have correct error handling on the property
functions will make the warning go away and fix the bug you pointed
out, so we should definitely do that and drop my patch.

	Arnd