tracing: Adding NULL checks for trace_array descriptor pointer

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>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index fa4f742..79fe4d6 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3297,6 +3297,9 @@ 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 fba87d1..2a3ac23 100644 (file)
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -793,6 +793,8 @@ 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.