Re: [PATCH] x86/ftrace: Exclude functions in head64.c from function-tracing

Steven Rostedt
2017-06-27T13:38:34Z

On Tue, 27 Jun 2017 14:59:48 +0300
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> wrote:

> We've moved most logic of early boot up from startup_64() written in
> assembly to __startup_64() written in C.
>
> Fengguang reported breakage due to the change. It was tracked down to
> CONFIG_FUNCTION_TRACER being enabled.

Is this due to code that is in linux-next or is this issue currently in
mainline?

If it is in linux-next, I'll give you:

Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

and you can take it. If the issue happens in current mainline, then I'll
take it and push it out.

-- Steve

>
> Looks like function-tracing of the new code is harmful.
>
> Let's not comple the code with -pg compiler option.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Reported-by: Fengguang Wu <fengguang.wu@intel.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> ---
> arch/x86/kernel/Makefile | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
> index 4b994232cb57..0db512092f37 100644
> --- a/arch/x86/kernel/Makefile
> +++ b/arch/x86/kernel/Makefile
> @@ -18,6 +18,7 @@ CFLAGS_REMOVE_pvclock.o = -pg
> CFLAGS_REMOVE_kvmclock.o = -pg
> CFLAGS_REMOVE_ftrace.o = -pg
> CFLAGS_REMOVE_early_printk.o = -pg
> +CFLAGS_REMOVE_head64.o = -pg
> endif
>
> KASAN_SANITIZE_head$(BITS).o := n