On Tue, 2016-08-23 at 08:05 -0700, Joe Perches wrote: > A compiler does not have a standards based requirement to > initialize arbitrary padding bytes. > > I believe gcc always does zero all padding anyway.
I would not worry for kernel code, because the amount of scrutiny there will be enough to 'fix potential bugs' [1], but a lot of user land code would suffer from various bugs as well that might sit there forever. [1] Also, most call sites in the kernel are using same call stack, so the offset of '1-7 leaked bytes' vs kernel stack is constant, making exploits quite challenging. Even if the current standards are lazy (are they, I did not check ?), security needs would call for a sane compiler behavior and changing the standards accordingly.