From: Divya Indi <divya.i...@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.i...@oracle.com

Signed-off-by: Divya Indi <divya.i...@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rost...@goodmis.org>
Signed-off-by: Sasha Levin <sas...@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 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



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