This is the mail archive of the
systemtap@sourceware.org
mailing list for the systemtap project.
Re: [PATCH -tip v8 07/26] [BUGFIX] x86: Prohibit probing on thunk functions and restore
- From: Steven Rostedt <rostedt at goodmis dot org>
- To: Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>
- Cc: linux-kernel at vger dot kernel dot org, Ingo Molnar <mingo at kernel dot org>, Andi Kleen <andi at firstfloor dot org>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Sandeepa Prabhu <sandeepa dot prabhu at linaro dot org>, Frederic Weisbecker <fweisbec at gmail dot com>, x86 at kernel dot org, fche at redhat dot com, mingo at redhat dot com, systemtap at sourceware dot org, "H. Peter Anvin" <hpa at zytor dot com>, Thomas Gleixner <tglx at linutronix dot de>
- Date: Fri, 21 Mar 2014 21:00:20 -0400
- Subject: Re: [PATCH -tip v8 07/26] [BUGFIX] x86: Prohibit probing on thunk functions and restore
- Authentication-results: sourceware.org; auth=none
- References: <20140305115843 dot 22766 dot 8355 dot stgit at ltc230 dot yrl dot intra dot hitachi dot co dot jp> <20140305115932 dot 22766 dot 76074 dot stgit at ltc230 dot yrl dot intra dot hitachi dot co dot jp>
On Wed, 05 Mar 2014 20:59:32 +0900
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> wrote:
> thunk_ra trace_hardirqs_on_thunk,trace_hardirqs_on_caller
> diff --git a/arch/x86/lib/thunk_64.S b/arch/x86/lib/thunk_64.S
> index a63efd6..92d9fea 100644
> --- a/arch/x86/lib/thunk_64.S
> +++ b/arch/x86/lib/thunk_64.S
> @@ -8,6 +8,7 @@
> #include <linux/linkage.h>
> #include <asm/dwarf2.h>
> #include <asm/calling.h>
> +#include <asm/asm.h>
>
> /* rdi: arg1 ... normal C conventions. rax is saved/restored. */
> .macro THUNK name, func, put_ret_addr_in_rdi=0
> @@ -25,6 +26,7 @@
> call \func
> jmp restore
> CFI_ENDPROC
> + _ASM_NOKPROBE(\name)
> .endm
>
> #ifdef CONFIG_TRACE_IRQFLAGS
> @@ -43,3 +45,4 @@ restore:
> RESTORE_ARGS
> ret
> CFI_ENDPROC
> + _ASM_NOKPROBE(restore)
>
Does kallsyms return something for this? I'm curious to what it does.
It might find something that we didn't expect. Do you have debug code
to list out all the black listed items found at boot up?
-- Steve