regmap: fix possible ZERO_SIZE_PTR pointer dereferencing error.

Since we cannot make sure the 'val_count' will always be none zero
here, and then if it equals to zero, the kmemdup() will return
ZERO_SIZE_PTR, which equals to ((void *)16).

So this patch fix this with just doing the zero check before calling
kmemdup().

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index b903aff59af3..e677a1b79f95 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1659,6 +1659,9 @@ out:
         } else {
                 void *wval;
 
+                if (!val_count)
+                        return -EINVAL;
+
                 wval = kmemdup(val, val_count * val_bytes, GFP_KERNEL);
                 if (!wval) {
                         dev_err(map->dev, "Error in memory allocation\n");