Re: [PATCH] structleak: disable BYREF_ALL in combination with KASAN_STACK

Kees Cook
2019-06-20T17:36:01Z

On Tue, Jun 18, 2019 at 11:47:13AM +0200, Arnd Bergmann wrote:
> The combination of KASAN_STACK and GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
> leads to much larger kernel stack usage, as seen from the warnings
> about functions that now exceed the 2048 byte limit:

Is the preference that this go into v5.2 (there's not much time left),
or should this be v5.3? (You didn't mark it as Cc: stable?)

> one. I picked the dependency in GCC_PLUGIN_STRUCTLEAK_BYREF_ALL, as
> this option is designed to make uninitialized stack usage less harmful
> when enabled on its own, but it also prevents KASAN from detecting those
> cases in which it was in fact needed.

Right -- there's not much sense in both being enabled. I'd agree with
this rationale.

--
Kees Cook