[PATCH] power: supply: sysfs: Remove duplicate NUL termination

[PATCH] power: supply: sysfs: Remove duplicate NUL termination

[Kees Cook]

GCC 15's new -Wunterminated-string-initialization notices that one of
the sysfs attr strings would lack the implicit trailing NUL byte during
initialization:

drivers/power/supply/power_supply_sysfs.c:183:57: warning: initializer-string for array of 'char' truncates NUL terminator but destination lacks 'nonstring' attribute (32 chars into 31 available) [-Wunterminated-string-initialization]
  183 |         POWER_SUPPLY_ATTR(CHARGE_CONTROL_START_THRESHOLD),
      |                                                         ^
drivers/power/supply/power_supply_sysfs.c:36:23: note: in definition of macro '_POWER_SUPPLY_ATTR'
   36 |         .attr_name = #_name "\0",               \
      |                       ^~~~~
drivers/power/supply/power_supply_sysfs.c:183:9: note: in expansion of macro 'POWER_SUPPLY_ATTR'
  183 |         POWER_SUPPLY_ATTR(CHARGE_CONTROL_START_THRESHOLD),
      |         ^~~~~~~~~~~~~~~~~

However, the macro used was explicitly adding a trailing NUL byte (which
is not needed). Remove this to avoid the GCC warning. No binary
differences are seen after this change (there was always run for a NUL
byte, it's just that the _second_ NUL byte was getting truncated).

Signed-off-by: Kees Cook <kees@kernel.org>
---
Cc: Sebastian Reichel <sre@kernel.org>
Cc: <linux-pm@vger.kernel.org>
---
 drivers/power/supply/power_supply_sysfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c
index edb058c19c9c..439dd0bf8644 100644
--- a/drivers/power/supply/power_supply_sysfs.c
+++ b/drivers/power/supply/power_supply_sysfs.c
@@ -33,7 +33,7 @@ struct power_supply_attr {
 [POWER_SUPPLY_PROP_ ## _name] =			\
 {						\
 	.prop_name = #_name,			\
-	.attr_name = #_name "\0",		\
+	.attr_name = #_name,			\
 	.text_values = _text,			\
 	.text_values_len = _len,		\
 }
-- 
2.34.1

Re: [PATCH] power: supply: sysfs: Remove duplicate NUL termination

[Sebastian Reichel]

On Wed, 16 Apr 2025 15:27:41 -0700, Kees Cook wrote:
> GCC 15's new -Wunterminated-string-initialization notices that one of
> the sysfs attr strings would lack the implicit trailing NUL byte during
> initialization:
> 
> drivers/power/supply/power_supply_sysfs.c:183:57: warning: initializer-string for array of 'char' truncates NUL terminator but destination lacks 'nonstring' attribute (32 chars into 31 available) [-Wunterminated-string-initialization]
>   183 |         POWER_SUPPLY_ATTR(CHARGE_CONTROL_START_THRESHOLD),
>       |                                                         ^
> drivers/power/supply/power_supply_sysfs.c:36:23: note: in definition of macro '_POWER_SUPPLY_ATTR'
>    36 |         .attr_name = #_name "\0",               \
>       |                       ^~~~~
> drivers/power/supply/power_supply_sysfs.c:183:9: note: in expansion of macro 'POWER_SUPPLY_ATTR'
>   183 |         POWER_SUPPLY_ATTR(CHARGE_CONTROL_START_THRESHOLD),
>       |         ^~~~~~~~~~~~~~~~~
> 
> [...]

Applied, thanks!

[1/1] power: supply: sysfs: Remove duplicate NUL termination
      commit: 77f5bb150132bbbcd6bc37ffdc80c9e140e373a4

Best regards,
-- 
Sebastian Reichel <sebastian.reichel@collabora.com>