Re: [PATCH 3/3] kprobes/x86: stacktool: ignore kretprobe_trampoline_holder

[Josh Poimboeuf]

On Thu, Sep 17, 2015 at 05:14:37PM -0500, Chris J Arges wrote:
> The function kretprobe_trampoline_holder isn't called explicility and therefore
> should be ignored by stacktool.
> 
> Signed-off-by: Chris J Arges <chris.j.arges@xxxxxxxxxxxxx>
> ---
>  arch/x86/kernel/kprobes/core.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
> index 1deffe6..3ade909 100644
> --- a/arch/x86/kernel/kprobes/core.c
> +++ b/arch/x86/kernel/kprobes/core.c
> @@ -49,6 +49,7 @@
>  #include <linux/kdebug.h>
>  #include <linux/kallsyms.h>
>  #include <linux/ftrace.h>
> +#include <linux/stacktool.h>
>  
>  #include <asm/cacheflush.h>
>  #include <asm/desc.h>
> @@ -704,6 +705,7 @@ static void __used kretprobe_trampoline_holder(void)
>  }
>  NOKPROBE_SYMBOL(kretprobe_trampoline_holder);
>  NOKPROBE_SYMBOL(kretprobe_trampoline);
> +STACKTOOL_IGNORE_FUNC(kretprobe_trampoline_holder);
>  
>  /*
>   * Called from kretprobe_trampoline
> -- 
> 1.9.1

The kretprobe trampoline isn't called directly but it can still be
executed at runtime.  I think we should make sure it does the "right
thing" with respect to frame pointers and CFI before telling stacktool
to ignore it.

-- 
Josh
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