Re: [PATCH] x86/alternative: Report missing return thunk details

[Josh Poimboeuf]

On Wed, Jul 13, 2022 at 02:38:19PM -0700, Kees Cook wrote:
> Debugging missing return thunks is easier if we can see where they're
> happening.
> 
> Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Link: https://lore.kernel.org/lkml/Ys66hwtFcGbYmoiZ@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: x86@xxxxxxxxxx
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---
>  arch/x86/kernel/alternative.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
> index d6858533e6e5..62f6b8b7c4a5 100644
> --- a/arch/x86/kernel/alternative.c
> +++ b/arch/x86/kernel/alternative.c
> @@ -555,7 +555,9 @@ void __init_or_module noinline apply_returns(s32 *start, s32 *end)
>  			dest = addr + insn.length + insn.immediate.value;
>  
>  		if (__static_call_fixup(addr, op, dest) ||
> -		    WARN_ON_ONCE(dest != &__x86_return_thunk))
> +		    WARN_ONCE(dest != &__x86_return_thunk,
> +			      "missing return thunk: %pS-%pS: %*ph",
> +			      addr, dest, 5, addr))

String needs a newline?

-- 
Josh