On Wed, Mar 10, 2021 at 03:56:02PM -0800, Andrew Morton wrote:
On Tue, 9 Mar 2021 13:42:55 -0800 Kees Cook keescook@chromium.org wrote:
Choosing the initial state of static branches changes the assembly layout (if the condition is expected to be likely, inline, or unlikely, out of line via a jump). The _TRUE/_FALSE defines for CONFIG_INIT_ON_*_DEFAULT_ON were accidentally removed. These need to stay so that the CONFIG controls the pessimization of the resulting static branch NOP/JMP locations.
Changelog doesn't really explain why anyone would want to apply this patch. This is especially important for -stable patches.
IOW, what is the user visible effect of the bug?
Yeah, that's a good point, and in writing more details I decided this wasn't actually worth a stable patch, and should just get folded into later patches.
Thanks for the sanity-check!