X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;ds=sidebyside;f=kernel%2Ftrace%2Ftrace_printk.c;h=ad1d6164e94603cf29f1b26f0a58f8c37988d57b;hb=79df8fa79b6a2aced892ad2b2c9832e7d9bdea6b;hp=1c2b28536feb8113a408b2335c38fb0a0c4272e1;hpb=b4a237598aa740562f842db76d97465c44fb74c1;p=firefly-linux-kernel-4.4.55.git

diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index 1c2b28536feb..ad1d6164e946 100644
--- a/kernel/trace/trace_printk.c
+++ b/kernel/trace/trace_printk.c
@@ -36,6 +36,10 @@ struct trace_bprintk_fmt {
 static inline struct trace_bprintk_fmt *lookup_format(const char *fmt)
 {
 	struct trace_bprintk_fmt *pos;
+
+	if (!fmt)
+		return ERR_PTR(-EINVAL);
+
 	list_for_each_entry(pos, &trace_bprintk_fmt_list, list) {
 		if (!strcmp(pos->fmt, fmt))
 			return pos;
@@ -57,7 +61,8 @@ void hold_module_trace_bprintk_format(const char **start, const char **end)
 	for (iter = start; iter < end; iter++) {
 		struct trace_bprintk_fmt *tb_fmt = lookup_format(*iter);
 		if (tb_fmt) {
-			*iter = tb_fmt->fmt;
+			if (!IS_ERR(tb_fmt))
+				*iter = tb_fmt->fmt;
 			continue;
 		}
 
@@ -273,6 +278,7 @@ static const char **find_next(void *v, loff_t *pos)
 	if (*pos < last_index + start_index)
 		return __start___tracepoint_str + (*pos - last_index);
 
+	start_index += last_index;
 	return find_next_mod_format(start_index, v, fmt, pos);
 }
 
@@ -295,6 +301,9 @@ static int t_show(struct seq_file *m, void *v)
 	const char *str = *fmt;
 	int i;
 
+	if (!*fmt)
+		return 0;
+
 	seq_printf(m, "0x%lx : \"", *(unsigned long *)fmt);
 
 	/*