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Commit a342a028 authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Steven Rostedt
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tracing/kprobes: Init print_fmt for kprobe events 



This is part of a patch set that removes the show_format method
in the ftrace event macros.

Add the print_fmt initialization to the kprobe events.
The print_fmt is still not used, but will be in the follow up
patches.

Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B273D45.3080100@cn.fujitsu.com>
Acked-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 50307a45

kernel/trace/trace_kprobe.c

+63 −1
Original line number Diff line number Diff line
@@ -1250,6 +1250,62 @@ static int kretprobe_event_show_format(struct ftrace_event_call *call, 
					 ", REC->" FIELD_STRING_RETIP);

}



static int __set_print_fmt(struct trace_probe *tp, char *buf, int len)

{

	int i;

	int pos = 0;



	const char *fmt, *arg;



	if (!probe_is_return(tp)) {

		fmt = "(%lx)";

		arg = "REC->" FIELD_STRING_IP;

	} else {

		fmt = "(%lx <- %lx)";

		arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;

	}



	/* When len=0, we just calculate the needed length */

#define LEN_OR_ZERO (len ? len - pos : 0)



	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);



	for (i = 0; i < tp->nr_args; i++) {

		pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%%lx",

				tp->args[i].name);

	}



	pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);



	for (i = 0; i < tp->nr_args; i++) {

		pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",

				tp->args[i].name);

	}



#undef LEN_OR_ZERO



	/* return the length of print_fmt */

	return pos;

}



static int set_print_fmt(struct trace_probe *tp)

{

	int len;

	char *print_fmt;



	/* First: called with 0 length to calculate the needed length */

	len = __set_print_fmt(tp, NULL, 0);

	print_fmt = kmalloc(len + 1, GFP_KERNEL);

	if (!print_fmt)

		return -ENOMEM;



	/* Second: actually write the @print_fmt */

	__set_print_fmt(tp, print_fmt, len + 1);

	tp->call.print_fmt = print_fmt;



	return 0;

}



#ifdef CONFIG_EVENT_PROFILE



/* Kprobe profile handler */
@@ -1456,10 +1512,14 @@ static int register_probe_event(struct trace_probe *tp) 
		call->show_format = kprobe_event_show_format;

		call->define_fields = kprobe_event_define_fields;

	}

	if (set_print_fmt(tp) < 0)

		return -ENOMEM;

	call->event = &tp->event;

	call->id = register_ftrace_event(&tp->event);

	if (!call->id)

	if (!call->id) {

		kfree(call->print_fmt);

		return -ENODEV;

	}

	call->enabled = 0;

	call->regfunc = probe_event_enable;

	call->unregfunc = probe_event_disable;
@@ -1472,6 +1532,7 @@ static int register_probe_event(struct trace_probe *tp) 
	ret = trace_add_event_call(call);

	if (ret) {

		pr_info("Failed to register kprobe event: %s\n", call->name);

		kfree(call->print_fmt);

		unregister_ftrace_event(&tp->event);

	}

	return ret;
@@ -1481,6 +1542,7 @@ static void unregister_probe_event(struct trace_probe *tp) 
{

	/* tp->event is unregistered in trace_remove_event_call() */

	trace_remove_event_call(&tp->call);

	kfree(tp->call.print_fmt);

}



/* Make a debugfs interface for controling probe points */