From: Arnd Bergmann <arnd@xxxxxxxx> gcc-11 warns when building with W=1: drivers/leds/led-class-flash.c: In function 'flash_fault_show': drivers/leds/led-class-flash.c:210:16: error: 'sprintf' argument 3 overlaps destination object 'buf' [-Werror=restrict] 210 | return sprintf(buf, "%s\n", buf); | ^~~~~~~~~~~~~~~~~~~~~~~~~ drivers/leds/led-class-flash.c:187:54: note: destination object referenced by 'restrict'-qualified argument 1 was declared here 187 | struct device_attribute *attr, char *buf) | ~~~~~~^~~ There is no need for the sprintf() here when a strcat() does the same thing without invoking undefined behavior. Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> --- drivers/leds/led-class-flash.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/leds/led-class-flash.c b/drivers/leds/led-class-flash.c index 185e17055317..6fe9d700dfef 100644 --- a/drivers/leds/led-class-flash.c +++ b/drivers/leds/led-class-flash.c @@ -207,7 +207,7 @@ static ssize_t flash_fault_show(struct device *dev, mask <<= 1; } - return sprintf(buf, "%s\n", buf); + return strlen(strcat(buf, "\n")); } static DEVICE_ATTR_RO(flash_fault); -- 2.29.2