Re: [PATCH v3 15/16] x86, kprobes: Fix optprobe_template_func type mismatch

[Kees Cook]

On Tue, Sep 14, 2021 at 12:10:44PM -0700, Sami Tolvanen wrote:
> The optprobe_template_func symbol is defined in inline assembly,
> but it's not marked global, which conflicts with the C declaration
> needed for STACK_FRAME_NON_STANDARD and confuses the compiler when
> CONFIG_CFI_CLANG is enabled.
> 
> Marking the symbol global would make the compiler happy, but as the
> compiler also generates a CFI jump table entry for all address-taken
> functions, the jump table ends up containing a jump to the .rodata
> section where optprobe_template_func resides, which results in an
> objtool warning.
> 
> Use ASM_STACK_FRAME_NON_STANDARD instead to avoid both issues.
> 
> Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

-- 
Kees Cook