On 24/11/2015 at 14:51:24 +0100, Rasmus Villemoes wrote : > ...and don't do it wrong. > > "not ok or N/A" has length 13. Add the trailing newline, and the > snprintf return value will be 14. However, we lied to snprintf and > told it that only 13 bytes were available. Hence snprintf has only > written "not ok or N/" and a trailing '\0' to the buffer. Next we > continue lying, this time to the upper sysfs layer, claiming that we > wrote 14 meaningful bytes to the buffer. That'll make the upper layer > copy "not ok or N/" plus two nul bytes to user space (one nul byte > from snprintf, the other since sysfs takes care to clear the buffer > before giving it to the ->show method). > > In the other cases, the claimed buffer size is closer to sufficient, > but we'll still get a nul byte instead of a newline written to user > space. There's absolutely no reason to try to predict the output > size, and there's plenty of room in the buffer, so just use sprintf. > > Signed-off-by: Rasmus Villemoes <[email protected]> > --- > drivers/rtc/rtc-ds1685.c | 12 +++++------- > 1 file changed, 5 insertions(+), 7 deletions(-) > Applied, thanks.
-- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
