[PATCH 4.9 023/121] tracing: Adding NULL checks for trace_array descriptor pointer

[Greg Kroah-Hartman]

From: Divya Indi <divya.indi@xxxxxxxxxx>

[ Upstream commit 953ae45a0c25e09428d4a03d7654f97ab8a36647 ]

As part of commit f45d1225adb0 ("tracing: Kernel access to Ftrace
instances") we exported certain functions. Here, we are adding some additional
NULL checks to ensure safe usage by users of these APIs.

Link: http://lkml.kernel.org/r/1565805327-579-4-git-send-email-divya.indi@xxxxxxxxxx

Signed-off-by: Divya Indi <divya.indi@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 kernel/trace/trace.c        | 3 +++
 kernel/trace/trace_events.c | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index b2fb25aefb2fc..67cee2774a6b8 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2600,6 +2600,9 @@ int trace_array_printk(struct trace_array *tr,
 	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
 		return 0;
 
+	if (!tr)
+		return -ENOENT;
+
 	va_start(ap, fmt);
 	ret = trace_array_vprintk(tr, ip, fmt, ap);
 	va_end(ap);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index af969f753e5e9..5bf072e437c41 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -790,6 +790,8 @@ static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
 	char *event = NULL, *sub = NULL, *match;
 	int ret;
 
+	if (!tr)
+		return -ENOENT;
 	/*
 	 * The buf format can be <subsystem>:<event-name>
 	 *  *:<event-name> means any event by that name.
-- 
2.25.1