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From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
	Ingo Molnar <mingo@redhat.com>,
	linux-kernel@vger.kernel.org,
	Tom Zanussi <tom.zanussi@linux.intel.com>,
	Ravi Bangoria <ravi.bangoria@linux.ibm.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Arnaldo Carvalho de Melo <acme@kernel.org>
Subject: [PATCH v2 06/12] tracing/kprobe: Add per-probe delete from event
Date: Thu, 20 Jun 2019 00:08:08 +0900
Message-ID: <156095688848.28024.15798690082378432435.stgit@devnote2> (raw)
In-Reply-To: <156095682948.28024.14190188071338900568.stgit@devnote2>

Allow user to delete a probe from event. This is done by head
match. For example, if we have 2 probes on an event

$ cat kprobe_events
p:kprobes/testprobe _do_fork r1=%ax r2=%dx
p:kprobes/testprobe idle_fork r1=%ax r2=%cx

Then you can remove one of them by passing the head of definition
which identify the probe.

$ echo "-:kprobes/testprobe idle_fork" >> kprobe_events

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 kernel/trace/trace_kprobe.c |   25 ++++++++++++++++++++++++-
 kernel/trace/trace_probe.c  |   18 ++++++++++++++++++
 kernel/trace/trace_probe.h  |    2 ++
 3 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index f43098bf62dd..18c4175b6585 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -137,13 +137,36 @@ static bool trace_kprobe_is_busy(struct dyn_event *ev)
 	return trace_probe_is_enabled(&tk->tp);
 }
 
+static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
+					    int argc, const char **argv)
+{
+	char buf[MAX_ARGSTR_LEN + 1];
+
+	if (!argc)
+		return true;
+
+	if (!tk->symbol)
+		snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
+	else if (tk->rp.kp.offset)
+		snprintf(buf, sizeof(buf), "%s+%u",
+			 trace_kprobe_symbol(tk), tk->rp.kp.offset);
+	else
+		snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
+	if (strcmp(buf, argv[0]))
+		return false;
+	argc--; argv++;
+
+	return trace_probe_match_command_args(&tk->tp, argc, argv);
+}
+
 static bool trace_kprobe_match(const char *system, const char *event,
 			int argc, const char **argv, struct dyn_event *ev)
 {
 	struct trace_kprobe *tk = to_trace_kprobe(ev);
 
 	return strcmp(trace_probe_name(&tk->tp), event) == 0 &&
-	    (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0);
+	    (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
+	    trace_kprobe_match_command_head(tk, argc, argv);
 }
 
 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 651a1449acde..f8c3c65c035d 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -1047,3 +1047,21 @@ int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
 
 	return 0;
 }
+
+bool trace_probe_match_command_args(struct trace_probe *tp,
+				    int argc, const char **argv)
+{
+	char buf[MAX_ARGSTR_LEN + 1];
+	int i;
+
+	if (tp->nr_args < argc)
+		return false;
+
+	for (i = 0; i < argc; i++) {
+		snprintf(buf, sizeof(buf), "%s=%s",
+			 tp->args[i].name, tp->args[i].comm);
+		if (strcmp(buf, argv[i]))
+			return false;
+	}
+	return true;
+}
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 39926e8a344b..2dcc4e317787 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -332,6 +332,8 @@ int trace_probe_remove_file(struct trace_probe *tp,
 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
 						struct trace_event_file *file);
 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b);
+bool trace_probe_match_command_args(struct trace_probe *tp,
+				    int argc, const char **argv);
 
 #define trace_probe_for_each_link(pos, tp)	\
 	list_for_each_entry(pos, &(tp)->event->files, list)


  parent reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-19 15:07 [PATCH v2 00/12] tracing/probe: Add multi-probes per event support Masami Hiramatsu
2019-06-19 15:07 ` [PATCH v2 01/12] tracing/probe: Split trace_event related data from trace_probe Masami Hiramatsu
2019-06-19 15:07 ` [PATCH v2 02/12] tracing/dynevent: Delete all matched events Masami Hiramatsu
2019-06-19 15:07 ` [PATCH v2 03/12] tracing/dynevent: Pass extra arguments to match operation Masami Hiramatsu
2019-06-19 15:07 ` [PATCH v2 04/12] tracing/kprobe: Add multi-probe per event support Masami Hiramatsu
2019-06-19 15:07 ` [PATCH v2 05/12] tracing/uprobe: Add multi-probe per uprobe " Masami Hiramatsu
2019-06-19 15:08 ` Masami Hiramatsu [this message]
2019-06-19 15:08 ` [PATCH v2 07/12] tracing/uprobe: Add per-probe delete from event Masami Hiramatsu
2019-06-19 15:08 ` [PATCH v2 08/12] tracing/probe: Add immediate parameter support Masami Hiramatsu
2019-06-19 15:08 ` [PATCH v2 09/12] tracing/probe: Add immediate string " Masami Hiramatsu
2019-06-19 15:08 ` [PATCH v2 10/12] selftests/ftrace: Add a testcase for kprobe multiprobe event Masami Hiramatsu
2019-06-19 15:08 ` [PATCH v2 11/12] selftests/ftrace: Add syntax error test for immediates Masami Hiramatsu
2019-06-19 15:09 ` [PATCH v2 12/12] selftests/ftrace: Add syntax error test for multiprobe Masami Hiramatsu
2019-07-04  6:39 ` [PATCH v2 00/12] tracing/probe: Add multi-probes per event support Masami Hiramatsu
2019-07-04 11:28   ` Steven Rostedt
2019-07-30  6:23     ` Masami Hiramatsu
2019-07-30 15:03       ` Steven Rostedt
2019-07-31 15:25 ` Steven Rostedt
2019-08-01 14:01   ` Masami Hiramatsu

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