* [PATCH] acpi: avoid uninialized-variable warning
@ 2020-04-28 21:55 Arnd Bergmann
2020-04-28 22:08 ` Andy Shevchenko
0 siblings, 1 reply; 2+ messages in thread
From: Arnd Bergmann @ 2020-04-28 21:55 UTC (permalink / raw)
To: Rafael J. Wysocki, Len Brown
Cc: Arnd Bergmann, Andy Shevchenko, Rob Herring, Sakari Ailus,
Pierre-Louis Bossart, Mika Westerberg, Thomas Gleixner,
Heikki Krogerus, Geert Uytterhoeven, linux-acpi, linux-kernel
Older compilers like gcc-4.8 produce a bogus warning here
In file included from include/linux/compiler_types.h:68:0,
from <command-line>:0:
drivers/acpi/property.c: In function 'acpi_data_prop_read':
include/linux/compiler-gcc.h:75:45: error: 'obj' may be used uninitialized in this function [-Werror=maybe-uninitialized]
#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
^
drivers/acpi/property.c:934:27: note: 'obj' was declared here
const union acpi_object *obj;
^
Ensure the output is always initialized even when returning an error
to avoid the warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/acpi/property.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
index e601c4511a8b..3aa71daeb0b4 100644
--- a/drivers/acpi/property.c
+++ b/drivers/acpi/property.c
@@ -587,8 +587,10 @@ static int acpi_data_get_property_array(const struct acpi_device_data *data,
int ret, i;
ret = acpi_data_get_property(data, name, ACPI_TYPE_PACKAGE, &prop);
- if (ret)
+ if (ret && obj) {
+ *obj = NULL;
return ret;
+ }
if (type != ACPI_TYPE_ANY) {
/* Check that all elements are of correct type. */
--
2.26.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] acpi: avoid uninialized-variable warning
2020-04-28 21:55 [PATCH] acpi: avoid uninialized-variable warning Arnd Bergmann
@ 2020-04-28 22:08 ` Andy Shevchenko
0 siblings, 0 replies; 2+ messages in thread
From: Andy Shevchenko @ 2020-04-28 22:08 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Rafael J. Wysocki, Len Brown, Andy Shevchenko, Rob Herring,
Sakari Ailus, Pierre-Louis Bossart, Mika Westerberg,
Thomas Gleixner, Heikki Krogerus, Geert Uytterhoeven,
ACPI Devel Maling List, Linux Kernel Mailing List
On Wed, Apr 29, 2020 at 1:03 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
> Older compilers like gcc-4.8 produce a bogus warning here
>
> In file included from include/linux/compiler_types.h:68:0,
> from <command-line>:0:
> drivers/acpi/property.c: In function 'acpi_data_prop_read':
> include/linux/compiler-gcc.h:75:45: error: 'obj' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
> ^
> drivers/acpi/property.c:934:27: note: 'obj' was declared here
> const union acpi_object *obj;
> ^
>
> Ensure the output is always initialized even when returning an error
> to avoid the warning.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> drivers/acpi/property.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
> index e601c4511a8b..3aa71daeb0b4 100644
> --- a/drivers/acpi/property.c
> +++ b/drivers/acpi/property.c
> @@ -587,8 +587,10 @@ static int acpi_data_get_property_array(const struct acpi_device_data *data,
> int ret, i;
>
> ret = acpi_data_get_property(data, name, ACPI_TYPE_PACKAGE, &prop);
> - if (ret)
> + if (ret && obj) {
It changes semantics and requires obj to be non-NULL.
Should be
if (ret) {
if (obj)
*obj = NULL;
return ret;
}
> + *obj = NULL;
> return ret;
> + }
>
> if (type != ACPI_TYPE_ANY) {
> /* Check that all elements are of correct type. */
> --
> 2.26.0
>
--
With Best Regards,
Andy Shevchenko
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