Re: [PATCH 17/18] tracing: Add indirect to indirect access for function based events

[Steven Rostedt]

On Fri, 9 Feb 2018 10:47:58 -0500
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> Good catch!
> 
> It should have been:
> 
> 		return process_redirects(arg, val, buf);

Although I need to add this :-p

diff --git a/kernel/trace/trace_event_ftrace.c b/kernel/trace/trace_event_ftrace.c
index 673336e352be..2690d4e46322 100644
--- a/kernel/trace/trace_event_ftrace.c
+++ b/kernel/trace/trace_event_ftrace.c
@@ -562,7 +564,7 @@ process_event(struct func_event *fevent, const char *token, enum func_states sta
                ret = add_arg_redirect(fevent->last_arg, val, 0);
                if (ret)
                        break;
-               return FUNC_STATE_VAR;
+               return FUNC_STATE_BRACKET_END;
 
        case FUNC_STATE_REDIRECT_BRACKET:
                if (WARN_ON(!fevent->last_arg))
@@ -656,6 +658,7 @@ static unsigned long process_redirects(struct func_arg *arg, unsigned long val,
                        ret = probe_kernel_read(buf, (void *)val, sizeof(long));
                        if (ret)
                                return 0;
+                       val = *(unsigned long *)buf;
                }
        }
        return val;

Because it wasn't parsing properly, and then not getting the redirect.

-- Steve