[PATCH v4 net-next] dpll: Add an assertion to check freq_supported_num

[Jiasheng Jiang <jiashengjiangcool@gmail.com>]

Since the driver is broken in the case that src->freq_supported is not
NULL but src->freq_supported_num is 0, add an assertion for it.

Signed-off-by: Jiasheng Jiang <jiashengjiangcool@gmail.com>
---
Changelog:

v3 -> v4:

1. Add return after WARN_ON().

v2 -> v3:

1. Add "net-next" to the subject.
2. Remove the "Fixes" tag and "Cc: stable".
3. Replace BUG_ON with WARN_ON.

v1 -> v2:

1. Replace the check with an assertion.
---
 drivers/dpll/dpll_core.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/dpll/dpll_core.c b/drivers/dpll/dpll_core.c
index 32019dc33cca..940c26b9dd53 100644
--- a/drivers/dpll/dpll_core.c
+++ b/drivers/dpll/dpll_core.c
@@ -443,8 +443,11 @@ static void dpll_pin_prop_free(struct dpll_pin_properties *prop)
 static int dpll_pin_prop_dup(const struct dpll_pin_properties *src,
 			     struct dpll_pin_properties *dst)
 {
+	if (WARN_ON(src->freq_supported && !src->freq_supported_num))
+		return -EINVAL;
+
 	memcpy(dst, src, sizeof(*dst));
-	if (src->freq_supported && src->freq_supported_num) {
+	if (src->freq_supported) {
 		size_t freq_size = src->freq_supported_num *
 				   sizeof(*src->freq_supported);
 		dst->freq_supported = kmemdup(src->freq_supported,
-- 
2.25.1