# Re: \[PATCH v4 01/15\] stacktrace/x86: add function for detecting reliable stack traces

- From: Miroslav Benes \<mbenes@suse.cz\>
- Date: 2017-01-27 08:48:35 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2017/01/4921487
- Thread: https://ratatoskr.run/linuxppc-dev/2017/01/4916352/t.md

```text

> diff --git a/include/linux/stacktrace.h b/include/linux/stacktrace.h
> index 0a34489..8e8b67b 100644
> --- a/include/linux/stacktrace.h
> +++ b/include/linux/stacktrace.h
> @@ -18,6 +18,8 @@ extern void save_stack_trace_regs(struct pt_regs *regs,
>  				  struct stack_trace *trace);
>  extern void save_stack_trace_tsk(struct task_struct *tsk,
>  				struct stack_trace *trace);
> +extern int save_stack_trace_tsk_reliable(struct task_struct *tsk,
> +					 struct stack_trace *trace);
>  
>  extern void print_stack_trace(struct stack_trace *trace, int spaces);
>  extern int snprint_stack_trace(char *buf, size_t size,
> @@ -29,12 +31,12 @@ extern void save_stack_trace_user(struct stack_trace *trace);
>  # define save_stack_trace_user(trace)              do { } while (0)
>  #endif
>  
> -#else
> +#else /* !CONFIG_STACKTRACE */
>  # define save_stack_trace(trace)			do { } while (0)
>  # define save_stack_trace_tsk(tsk, trace)		do { } while (0)
>  # define save_stack_trace_user(trace)			do { } while (0)
>  # define print_stack_trace(trace, spaces)		do { } while (0)
>  # define snprint_stack_trace(buf, size, trace, spaces)	do { } while (0)

Is there a reason you did not define empty save_stack_trace_tsk_reliable() 
here? Right, it should not be needed now as livepatching is the only user, 
but still.

Miroslav
```