[PATCH] regmap: cache: Add extra parameter check in regcache_init

[Schspa Shi]

When num_reg_defaults > 0 but reg_defaults is NULL, there will be a
NULL pointer exception.

Current code has no such usage, but as additional hardening, also
check this to prevent any chance of crashing.

Signed-off-by: Schspa Shi <schspa@xxxxxxxxx>
---
 drivers/base/regmap/regcache.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index d0f5bc827978..d8c31c8ac4a0 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -133,6 +133,12 @@ int regcache_init(struct regmap *map, const struct regmap_config *config)
 		return -EINVAL;
 	}
 
+	if (config->num_reg_defaults && !config->reg_defaults) {
+		dev_err(map->dev,
+			"Register defaults number are set without the reg!\n");
+		return -EINVAL;
+	}
+
 	for (i = 0; i < config->num_reg_defaults; i++)
 		if (config->reg_defaults[i].reg % map->reg_stride)
 			return -EINVAL;
-- 
2.29.0