On Wed, Jun 01, 2022 at 12:50:47PM +0200, Lukas Bulwahn wrote:
> Dear Josh,
>
> Commit dbae0a934f09 ("x86/cpu: Remove CONFIG_X86_SMAP and "nosmap"")
> from Borislav removes the config X86_SMAP and makes smap on x86
> default.
>
> Josh, your commit 03f16cd020eb ("objtool: Add CONFIG_OBJTOOL") makes
> config UBSAN_UNREACHABLE in lib/Kconfig.ubsan refer to this
> non-existing config X86_SMAP.
>
> See this hunk in lib/Kconfig.ubsan:
>
> diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
> index f3c57ed51838..c4fe15d38b60 100644
> --- a/lib/Kconfig.ubsan
> +++ b/lib/Kconfig.ubsan
> @@ -94,7 +94,7 @@ config UBSAN_UNREACHABLE
> bool "Perform checking for unreachable code"
> # objtool already handles unreachable checking and gets angry about
> # seeing UBSan instrumentation located in unreachable places.
> - depends on !STACK_VALIDATION
> + depends on !(OBJTOOL && (STACK_VALIDATION || UNWINDER_ORC || X86_SMAP))
> depends on $(cc-option,-fsanitize=unreachable)
> help
> This option enables -fsanitize=unreachable which checks for control
>
> I think X86_SMAP can just be dropped in this line, but I leave it up
> to you to change, as I am not completely certain on the needed change
> and if that just breaks the config dependencies for stack validation.
>
> By the way, this issue was identified with the script
> ./scripts/checkkconfigsymbols.py
Hi Lukas,
Thanks for reporting this. I'll post a fix shortly.
--
Josh
