Re: [PATCH] objtool: Documentation: document UACCESS warnings

[Matt Helsley]

On Mon, Mar 23, 2020 at 05:13:20PM -0700, Nick Desaulniers wrote:
> Compiling with Clang and CONFIG_KASAN=y was exposing a few warnings:
>   call to memset() with UACCESS enabled
> 
> Document how to fix these for future travelers.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/876
> Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> ---
>  .../Documentation/stack-validation.txt        | 20 +++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/tools/objtool/Documentation/stack-validation.txt b/tools/objtool/Documentation/stack-validation.txt
> index de094670050b..156fee13ba02 100644
> --- a/tools/objtool/Documentation/stack-validation.txt
> +++ b/tools/objtool/Documentation/stack-validation.txt
> @@ -289,6 +289,26 @@ they mean, and suggestions for how to fix them.
>        might be corrupt due to a gcc bug.  For more details, see:
>        https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70646
>  
> +9. file.o: warning: objtool: funcA() call to funcB() with UACCESS enabled
> +
> +   This means that an unexpected call to a non-whitelisted function exists
> +   outside of arch-specific guards.
> +   X86: SMAP (stac/clac): __uaccess_begin()/__uaccess_end()
> +   ARM: PAN: uaccess_enable()/uaccess_enable()
I think you meant to put "disable" here  ^^^^^^

Cheers,
    -Matt Helsley