[PATCH -fixes v3 0/6] Fixes KASAN and other along the way

[Marco Elver]

On Fri, 25 Feb 2022 at 13:40, Alexandre Ghiti
<alexandre.ghiti at canonical.com> wrote:
>
> As reported by Aleksandr, syzbot riscv is broken since commit
> 54c5639d8f50 ("riscv: Fix asan-stack clang build"). This commit actually
> breaks KASAN_INLINE which is not fixed in this series, that will come later
> when found.
>
> Nevertheless, this series fixes small things that made the syzbot
> configuration + KASAN_OUTLINE fail to boot.
>
> Note that even though the config at [1] boots fine with this series, I
> was not able to boot the small config at [2] which fails because
> kasan_poison receives a really weird address 0x4075706301000000 (maybe a
> kasan person could provide some hint about what happens below in
> do_ctors -> __asan_register_globals):

asan_register_globals is responsible for poisoning redzones around
globals. As hinted by 'do_ctors', it calls constructors, and in this
case a compiler-generated constructor that calls
__asan_register_globals with metadata generated by the compiler. That
metadata contains information about global variables. Note, these
constructors are called on initial boot, but also every time a kernel
module (that has globals) is loaded.

It may also be a toolchain issue, but it's hard to say. If you're
using GCC to test, try Clang (11 or later), and vice-versa.