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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Masami Hiramatsu <mhiramat@kernel.org>
Subject: [for-next][PATCH 7/8] tracing/probe: Reject exactly same probe event
Date: Thu, 19 Sep 2019 19:23:20 -0400	[thread overview]
Message-ID: <20190919232400.470062819@goodmis.org> (raw)
In-Reply-To: 20190919232313.198902049@goodmis.org

From: Masami Hiramatsu <mhiramat@kernel.org>

Reject exactly same probe events as existing probes.

Multiprobe allows user to define multiple probes on same
event. If user appends a probe which exactly same definition
(same probe address and same arguments) on existing event,
the event will record same probe information twice.
That can be confusing users, so reject it.

Link: http://lkml.kernel.org/r/156879694602.31056.5533024778165036763.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c | 52 +++++++++++++++++++++++++++++++------
 kernel/trace/trace_probe.h  |  3 ++-
 kernel/trace/trace_uprobe.c | 52 +++++++++++++++++++++++++++++++------
 3 files changed, 90 insertions(+), 17 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 0ba3239c0270..a6697e28ddda 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -528,10 +528,53 @@ static int unregister_trace_kprobe(struct trace_kprobe *tk)
 	return 0;
 }
 
+static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
+					 struct trace_kprobe *comp)
+{
+	struct trace_probe_event *tpe = orig->tp.event;
+	struct trace_probe *pos;
+	int i;
+
+	list_for_each_entry(pos, &tpe->probes, list) {
+		orig = container_of(pos, struct trace_kprobe, tp);
+		if (strcmp(trace_kprobe_symbol(orig),
+			   trace_kprobe_symbol(comp)) ||
+		    trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
+			continue;
+
+		/*
+		 * trace_probe_compare_arg_type() ensured that nr_args and
+		 * each argument name and type are same. Let's compare comm.
+		 */
+		for (i = 0; i < orig->tp.nr_args; i++) {
+			if (strcmp(orig->tp.args[i].comm,
+				   comp->tp.args[i].comm))
+				continue;
+		}
+
+		return true;
+	}
+
+	return false;
+}
+
 static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
 {
 	int ret;
 
+	ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
+	if (ret) {
+		/* Note that argument starts index = 2 */
+		trace_probe_log_set_index(ret + 1);
+		trace_probe_log_err(0, DIFF_ARG_TYPE);
+		return -EEXIST;
+	}
+	if (trace_kprobe_has_same_kprobe(to, tk)) {
+		trace_probe_log_set_index(0);
+		trace_probe_log_err(0, SAME_PROBE);
+		return -EEXIST;
+	}
+
 	/* Append to existing event */
 	ret = trace_probe_append(&tk->tp, &to->tp);
 	if (ret)
@@ -568,14 +611,7 @@ static int register_trace_kprobe(struct trace_kprobe *tk)
 			trace_probe_log_err(0, DIFF_PROBE_TYPE);
 			ret = -EEXIST;
 		} else {
-			ret = trace_probe_compare_arg_type(&tk->tp, &old_tk->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_kprobe(tk, old_tk);
+			ret = append_trace_kprobe(tk, old_tk);
 		}
 		goto end;
 	}
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index f805cc4cbe7c..4ee703728aec 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -436,7 +436,8 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 	C(BAD_INSN_BNDRY,	"Probe point is not an instruction boundary"),\
 	C(FAIL_REG_PROBE,	"Failed to register probe event"),\
 	C(DIFF_PROBE_TYPE,	"Probe type is different from existing probe"),\
-	C(DIFF_ARG_TYPE,	"Argument type or name is different from existing probe"),
+	C(DIFF_ARG_TYPE,	"Argument type or name is different from existing probe"),\
+	C(SAME_PROBE,		"There is already the exact same probe event"),
 
 #undef C
 #define C(a, b)		TP_ERR_##a
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index cbf4da4bf367..34dd6d0016a3 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -410,10 +410,53 @@ static int unregister_trace_uprobe(struct trace_uprobe *tu)
 	return 0;
 }
 
+static bool trace_uprobe_has_same_uprobe(struct trace_uprobe *orig,
+					 struct trace_uprobe *comp)
+{
+	struct trace_probe_event *tpe = orig->tp.event;
+	struct trace_probe *pos;
+	struct inode *comp_inode = d_real_inode(comp->path.dentry);
+	int i;
+
+	list_for_each_entry(pos, &tpe->probes, list) {
+		orig = container_of(pos, struct trace_uprobe, tp);
+		if (comp_inode != d_real_inode(orig->path.dentry) ||
+		    comp->offset != orig->offset)
+			continue;
+
+		/*
+		 * trace_probe_compare_arg_type() ensured that nr_args and
+		 * each argument name and type are same. Let's compare comm.
+		 */
+		for (i = 0; i < orig->tp.nr_args; i++) {
+			if (strcmp(orig->tp.args[i].comm,
+				   comp->tp.args[i].comm))
+				continue;
+		}
+
+		return true;
+	}
+
+	return false;
+}
+
 static int append_trace_uprobe(struct trace_uprobe *tu, struct trace_uprobe *to)
 {
 	int ret;
 
+	ret = trace_probe_compare_arg_type(&tu->tp, &to->tp);
+	if (ret) {
+		/* Note that argument starts index = 2 */
+		trace_probe_log_set_index(ret + 1);
+		trace_probe_log_err(0, DIFF_ARG_TYPE);
+		return -EEXIST;
+	}
+	if (trace_uprobe_has_same_uprobe(to, tu)) {
+		trace_probe_log_set_index(0);
+		trace_probe_log_err(0, SAME_PROBE);
+		return -EEXIST;
+	}
+
 	/* Append to existing event */
 	ret = trace_probe_append(&tu->tp, &to->tp);
 	if (!ret)
@@ -469,14 +512,7 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
 			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);
+			ret = append_trace_uprobe(tu, old_tu);
 		}
 		goto end;
 	}
-- 
2.20.1



  parent reply	other threads:[~2019-09-19 23:24 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-19 23:23 [for-next][PATCH 0/8] tracing: Final updates before sending to Linus Steven Rostedt
2019-09-19 23:23 ` [for-next][PATCH 1/8] ftrace: Simplify ftrace hash lookup code in clear_func_from_hash() Steven Rostedt
2019-09-19 23:23 ` [for-next][PATCH 2/8] tracing: Be more clever when dumping hex in __print_hex() Steven Rostedt
2019-09-19 23:23 ` [for-next][PATCH 3/8] tracing: Make sure variable reference alias has correct var_ref_idx Steven Rostedt
     [not found]   ` <20190921120618.DF81120665@mail.kernel.org>
2019-09-21 12:20     ` Steven Rostedt
2019-09-21 19:21       ` Sasha Levin
2019-09-21 19:23         ` Steven Rostedt
2019-09-19 23:23 ` [for-next][PATCH 4/8] tracing/kprobe: Fix NULL pointer access in trace_porbe_unlink() Steven Rostedt
2019-09-19 23:23 ` [for-next][PATCH 5/8] selftests/ftrace: Select an existing function in kprobe_eventname test Steven Rostedt
2019-09-19 23:23 ` [for-next][PATCH 6/8] tracing/probe: Fix to allow user to enable events on unloaded modules Steven Rostedt
2019-09-19 23:23 ` Steven Rostedt [this message]
2019-09-23 10:42   ` [for-next][PATCH 7/8] tracing/probe: Reject exactly same probe event Srikar Dronamraju
2019-09-23 17:15     ` Masami Hiramatsu
2019-09-23 17:42       ` Srikar Dronamraju
2019-09-19 23:23 ` [for-next][PATCH 8/8] selftests/ftrace: Update kprobe event error testcase Steven Rostedt

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