tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure

PATCH In review Steven Rostedt 1 participant 1 message Jul 26, 2018

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Stable branch Tracing

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Steven Rostedt

author maintainer

2018-07-26 23:06 UTC #0 lore raw

PATCH 4/7 tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure

From: Artem Savkov <[email protected]>

If enable_trace_kprobe fails to enable the probe in enable_k(ret)probe it returns an error, but does not unset the tp flags it set previously. This results in a probe being considered enabled and failures like being unable to remove the probe through kprobe_events file since probes_open() expects every probe to be disabled.

Link http://lkml.kernel.org/r/[email protected] open here

Cc Ingo Molnar <[email protected]>

Cc [email protected]

Fixes 41a7dd420c57 ("tracing/kprobes: Support ftrace_event_file base multibuffer")

Acked-by Masami Hiramatsu <[email protected]>

Reviewed-by Josh Poimboeuf <[email protected]>

Signed-off-by Artem Savkov <[email protected]>

Signed-off-by Steven Rostedt (VMware) <[email protected]>

---
 kernel/trace/trace_kprobe.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

kernel/trace/trace_kprobe.c +11 -2

index 21f718472942..27ace4513c43 100644
@@ -400,11 +400,10 @@ static struct trace_kprobe *find_trace_kprobe(const char *event,
 static int
 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 {
+	struct event_file_link *link;
 	int ret = 0;
 
 	if (file) {
-		struct event_file_link *link;
-
 		link = kmalloc(sizeof(*link), GFP_KERNEL);
 		if (!link) {
 			ret = -ENOMEM;

@@ -424,6 +423,16 @@ enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 		else
 			ret = enable_kprobe(&tk->rp.kp);
 	}
+
+	if (ret) {
+		if (file) {
+			list_del_rcu(&link->list);
+			kfree(link);
+			tk->tp.flags &= ~TP_FLAG_TRACE;
+		} else {
+			tk->tp.flags &= ~TP_FLAG_PROFILE;
+		}
+	}
  out:
 	return ret;
 }

Signature · 1 line

2.17.1