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From: Masami Hiramatsu <>
To: Steven Rostedt <>
Subject: [PATCH 1/3] tracing/probe: Fix to allow user to enable events on unloaded modules
Date: Wed, 18 Sep 2019 17:55:37 +0900
Message-ID: <156879693733.31056.9331322616994665167.stgit@devnote2> (raw)
In-Reply-To: <156879692790.31056.9404391078827158266.stgit@devnote2>

Fix to allow user to enable probe events on unloaded modules.

This operations was allowed before commit 60d53e2c3b75 ("tracing/probe:
Split trace_event related data from trace_probe"), because if users
need to probe module init functions, they have to enable those probe
events before loading module.

Fixes: 60d53e2c3b75 ("tracing/probe: Split trace_event related data from trace_probe")
Signed-off-by: Masami Hiramatsu <>
 kernel/trace/trace_kprobe.c |   17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 7579c53bb053..0ba3239c0270 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -371,31 +371,24 @@ static int enable_trace_kprobe(struct trace_event_call *call,
 	if (enabled)
 		return 0;
-	enabled = false;
 	list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
 		tk = container_of(pos, struct trace_kprobe, tp);
 		if (trace_kprobe_has_gone(tk))
 		ret = __enable_trace_kprobe(tk);
-		if (ret) {
-			if (enabled) {
-				__disable_trace_kprobe(tp);
-				enabled = false;
-			}
+		if (ret)
-		}
 		enabled = true;
-	if (!enabled) {
-		/* No probe is enabled. Roll back */
+	if (ret) {
+		/* Failed to enable one of them. Roll back all */
+		if (enabled)
+			__disable_trace_kprobe(tp);
 		if (file)
 			trace_probe_remove_file(tp, file);
 			trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
-		if (!ret)
-			/* Since all probes are gone, this is not available */
 	return ret;

  reply index

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-18  8:55 [PATCH 0/3] tracing/probe: Fix some issues on multiprobe support Masami Hiramatsu
2019-09-18  8:55 ` Masami Hiramatsu [this message]
2019-09-18  8:55 ` [PATCH 2/3] tracing/probe: Reject exactly same probe event Masami Hiramatsu
2019-09-18  8:55 ` [PATCH 3/3] selftests/ftrace: Update kprobe event error testcase Masami Hiramatsu

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