Commit 4d655281 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt (VMware)
Browse files

tracing/boot Add kprobe event support 

Add kprobe event support on event node to boot-time tracing.
If the group name of event is "kprobes", the boot-time tracing
defines new probe event according to "probes" values.

 - ftrace.event.kprobes.EVENT.probes = PROBE[, PROBE2...]
   Defines new kprobe event based on PROBEs. It is able to define
   multiple probes on one event, but those must have same type of
   arguments.

For example,

 ftrace.events.kprobes.myevent {
	probes = "vfs_read $arg1 $arg2";
	enable;
 }

This will add kprobes:myevent on vfs_read with the 1st and the 2nd
arguments.

Link: http://lkml.kernel.org/r/157867240104.17873.9712052065426433111.stgit@devnote2



Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 81a59555

kernel/trace/trace_boot.c

+46 −0
Original line number Diff line number Diff line
@@ -76,6 +76,48 @@ trace_boot_enable_events(struct trace_array *tr, struct xbc_node *node) 
	}

}



#ifdef CONFIG_KPROBE_EVENTS

extern int trace_kprobe_run_command(const char *command);



static int __init

trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)

{

	struct xbc_node *anode;

	char buf[MAX_BUF_LEN];

	const char *val;

	char *p;

	int len;



	len = snprintf(buf, ARRAY_SIZE(buf) - 1, "p:kprobes/%s ", event);

	if (len >= ARRAY_SIZE(buf)) {

		pr_err("Event name is too long: %s\n", event);

		return -E2BIG;

	}

	p = buf + len;

	len = ARRAY_SIZE(buf) - len;



	xbc_node_for_each_array_value(node, "probes", anode, val) {

		if (strlcpy(p, val, len) >= len) {

			pr_err("Probe definition is too long: %s\n", val);

			return -E2BIG;

		}

		if (trace_kprobe_run_command(buf) < 0) {

			pr_err("Failed to add probe: %s\n", buf);

			return -EINVAL;

		}

	}



	return 0;

}

#else

static inline int __init

trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)

{

	pr_err("Kprobe event is not supported.\n");

	return -ENOTSUPP;

}

#endif



static void __init

trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,

			  struct xbc_node *enode)
@@ -88,6 +130,10 @@ trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode, 
	group = xbc_node_get_data(gnode);

	event = xbc_node_get_data(enode);



	if (!strcmp(group, "kprobes"))

		if (trace_boot_add_kprobe_event(enode, event) < 0)

			return;



	mutex_lock(&event_mutex);

	file = find_event_file(tr, group, event);

	if (!file) {

kernel/trace/trace_kprobe.c

+5 −0
Original line number Diff line number Diff line
@@ -902,6 +902,11 @@ static int create_or_delete_trace_kprobe(int argc, char **argv) 
	return ret == -ECANCELED ? -EINVAL : ret;

}



int trace_kprobe_run_command(const char *command)

{

	return trace_run_command(command, create_or_delete_trace_kprobe);

}



static int trace_kprobe_release(struct dyn_event *ev)

{

	struct trace_kprobe *tk = to_trace_kprobe(ev);

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