[PATCH AUTOSEL 4.4 09/64] tracing: Adding NULL checks for trace_array descriptor pointer

Sasha Levin
2020-09-18T02:23:26Z

From: Divya Indi <divya.indi@oracle.com>

[ 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@oracle.com

Signed-off-by: Divya Indi <divya.indi@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 06efd18bf3e38..17ea5f9d36b48 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2271,6 +2271,9 @@ 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 bd4c0bb61ad72..9d6e755d17546 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -755,6 +755,8 @@ 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