[PATCH 4/8] tracing/probe: Check maxactive error cases

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>

Check maxactive on kprobe error case, because maxactive
is only for kretprobe, not for kprobe. Also, maxactive
should not be 0, it should be at least 1.

Link: 155253780952.14922.15784129810238750331.stgit@devnote2">http://lkml.kernel.org/r/155253780952.14922.15784129810238750331.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
 kernel/trace/trace_kprobe.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index ceafa0a2b1d1..a14837545295 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -624,7 +624,11 @@ static int trace_kprobe_create(int argc, const char *argv[])
 	if (event)
 		event++;
 
-	if (is_return && isdigit(argv[0][1])) {
+	if (isdigit(argv[0][1])) {
+		if (!is_return) {
+			pr_info("Maxactive is not for kprobe");
+			return -EINVAL;
+		}
 		if (event)
 			len = event - &argv[0][1] - 1;
 		else
@@ -634,8 +638,8 @@ static int trace_kprobe_create(int argc, const char *argv[])
 		memcpy(buf, &argv[0][1], len);
 		buf[len] = '\0';
 		ret = kstrtouint(buf, 0, &maxactive);
-		if (ret) {
-			pr_info("Failed to parse maxactive.\n");
+		if (ret || !maxactive) {
+			pr_info("Invalid maxactive number\n");
 			return ret;
 		}
 		/* kretprobes instances are iterated over via a list. The
-- 
2.20.1