Commit 41af3cf5 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt (VMware)
Browse files

tracing/uprobe: Add multi-probe per uprobe event support 

Allow user to define several probes on one uprobe event.
Note that this only support appending method. So deleting
event will delete all probes on the event.

Link: http://lkml.kernel.org/r/156095687876.28024.13840331032234992863.stgit@devnote2



Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent ca89bc07

kernel/trace/trace.c

+1 −1
Original line number Diff line number Diff line
@@ -4823,7 +4823,7 @@ static const char readme_msg[] = 
	"\t\t\t  Write into this file to define/undefine new trace events.\n"

#endif

#ifdef CONFIG_UPROBE_EVENTS

	"  uprobe_events\t\t- Add/remove/show the userspace dynamic events\n"

	"  uprobe_events\t\t- Create/append/remove/show the userspace dynamic events\n"

	"\t\t\t  Write into this file to define/undefine new trace events.\n"

#endif

#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)

kernel/trace/trace_uprobe.c

+42 −18
Original line number Diff line number Diff line
@@ -364,15 +364,32 @@ static int unregister_trace_uprobe(struct trace_uprobe *tu) 
{

	int ret;



	if (trace_probe_has_sibling(&tu->tp))

		goto unreg;



	ret = unregister_uprobe_event(tu);

	if (ret)

		return ret;



unreg:

	dyn_event_remove(&tu->devent);

	trace_probe_unlink(&tu->tp);

	free_trace_uprobe(tu);

	return 0;

}



static int append_trace_uprobe(struct trace_uprobe *tu, struct trace_uprobe *to)

{

	int ret;



	/* Append to existing event */

	ret = trace_probe_append(&tu->tp, &to->tp);

	if (!ret)

		dyn_event_add(&tu->devent);



	return ret;

}



/*

 * Uprobe with multiple reference counter is not allowed. i.e.

 * If inode and offset matches, reference counter offset *must*
@@ -382,25 +399,21 @@ static int unregister_trace_uprobe(struct trace_uprobe *tu) 
 * as the new one does not conflict with any other existing

 * ones.

 */

static struct trace_uprobe *find_old_trace_uprobe(struct trace_uprobe *new)

static int validate_ref_ctr_offset(struct trace_uprobe *new)

{

	struct dyn_event *pos;

	struct trace_uprobe *tmp, *old = NULL;

	struct trace_uprobe *tmp;

	struct inode *new_inode = d_real_inode(new->path.dentry);



	old = find_probe_event(trace_probe_name(&new->tp),

				trace_probe_group_name(&new->tp));



	for_each_trace_uprobe(tmp, pos) {

		if ((old ? old != tmp : true) &&

		    new_inode == d_real_inode(tmp->path.dentry) &&

		if (new_inode == d_real_inode(tmp->path.dentry) &&

		    new->offset == tmp->offset &&

		    new->ref_ctr_offset != tmp->ref_ctr_offset) {

			pr_warn("Reference counter offset mismatch.");

			return ERR_PTR(-EINVAL);

			return -EINVAL;

		}

	}

	return old;

	return 0;

}



/* Register a trace_uprobe and probe_event */
@@ -411,17 +424,28 @@ static int register_trace_uprobe(struct trace_uprobe *tu) 


	mutex_lock(&event_mutex);



	/* register as an event */

	old_tu = find_old_trace_uprobe(tu);

	if (IS_ERR(old_tu)) {

		ret = PTR_ERR(old_tu);

	ret = validate_ref_ctr_offset(tu);

	if (ret)

		goto end;

	}



	/* register as an event */

	old_tu = find_probe_event(trace_probe_name(&tu->tp),

				  trace_probe_group_name(&tu->tp));

	if (old_tu) {

		/* delete old event */

		ret = unregister_trace_uprobe(old_tu);

		if (ret)

		if (is_ret_probe(tu) != is_ret_probe(old_tu)) {

			trace_probe_log_set_index(0);

			trace_probe_log_err(0, DIFF_PROBE_TYPE);

			ret = -EEXIST;

		} else {

			ret = trace_probe_compare_arg_type(&tu->tp, &old_tu->tp);

			if (ret) {

				/* Note that argument starts index = 2 */

				trace_probe_log_set_index(ret + 1);

				trace_probe_log_err(0, DIFF_ARG_TYPE);

				ret = -EEXIST;

			} else

				ret = append_trace_uprobe(tu, old_tu);

		}

		goto end;

	}