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From:   Divya Indi <divya.indi@oracle.com>
To:     Steven Rostedt <rostedt@goodmis.org>, linux-kernel@vger.kernel.org
Cc:     Divya Indi <divya.indi@oracle.com>, Joe Jin <joe.jin@oracle.com>,
        Srinivas Eeda <srinivas.eeda@oracle.com>,
        Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
Subject: [PATCH 3/5] tracing: Adding NULL checks
Date:   Wed, 14 Aug 2019 10:55:25 -0700
Message-Id: <1565805327-579-4-git-send-email-divya.indi@oracle.com>
In-Reply-To: <1565805327-579-1-git-send-email-divya.indi@oracle.com>
References: <1565805327-579-1-git-send-email-divya.indi@oracle.com>
Sender: linux-kernel-owner@vger.kernel.org
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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.

Signed-off-by: Divya Indi <divya.indi@oracle.com>
---
 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 468ecc5..22bf166 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3205,6 +3205,9 @@ 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 0ce3db6..2621995 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -800,6 +800,8 @@ 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.
-- 
1.8.3.1