Re: [PATCH v2] objtool: Documentation: document UACCESS warnings

From: Josh Poimboeuf
Date: Fri Apr 03 2020 - 12:20:51 EST


On Thu, Mar 26, 2020 at 11:37:06AM -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: Kamalesh Babulal <kamalesh@xxxxxxxxxxxxxxxxxx>
> Suggested-by: Matt Helsley <mhelsley@xxxxxxxxxx>
> Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Suggested-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> ---
> Changes V1 -> V2:
> * fix typo of listing uaccess_enable() twice rather than
> uaccess_disable() as per Matt and Kamalesh.
> * fix type of "should called" to "should be called" as per Randy.
> * Mention non-obvious compiler instrumentation ie. -pg/mcount
> -mfentry/fentry via tracing as per Peter.
> * Add sentence "It also helps verify..."
> * Add potential fix "1) remove explicit..."

Thanks, adding this one to the queue for tip.

--
Josh