Hi Kees,
On Fri, Feb 23, 2024 at 08:59:45AM -0800, Kees Cook wrote:
> The UBSAN instrumentation cannot work in the vDSO since it is executing
> in userspace, so disable it in the Makefile. Fixes the build failures
> such as:
>
> arch/sparc/vdso/vclock_gettime.c:217: undefined reference to `__ubsan_handle_shift_out_of_bounds'
>
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> Cc: Andreas Larsson <andreas@xxxxxxxxxxx>
> Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx>
> Cc: Sam Ravnborg <sam@xxxxxxxxxxxx>
> Cc: Helge Deller <deller@xxxxxx>
> Cc: Guo Ren <guoren@xxxxxxxxxx>
> Cc: sparclinux@xxxxxxxxxxxxxxx
> ---
> arch/sparc/vdso/Makefile | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/sparc/vdso/Makefile b/arch/sparc/vdso/Makefile
> index 7f5eedf1f5e0..e8aef2c8ae99 100644
> --- a/arch/sparc/vdso/Makefile
> +++ b/arch/sparc/vdso/Makefile
> @@ -2,6 +2,7 @@
> #
> # Building vDSO images for sparc.
> #
> +UBSAN_SANITIZE := n
When I read:
config UBSAN_SANITIZE_ALL
bool "Enable instrumentation for the entire kernel"
depends on ARCH_HAS_UBSAN_SANITIZE_ALL
default y
help
This option activates instrumentation for the entire kernel.
If you don't enable this option, you have to explicitly specify
UBSAN_SANITIZE := y for the files/directories you want to check for UB.
Enabling this option will get kernel image size increased
significantly.
I am left with the understanding that only arch's that
selects ARCH_HAS_UBSAN_SANITIZE_ALL would need to turn off
UBSAN_SANITIZE.
Are this fix papering over some other bug where we enable
UBSAN_SANITIZE_ALL for arch's that should not have it,
or something else that enable it?
Sam
