[PATCH 4.19 238/280] mfd: sm501: Fix potential NULL pointer dereference

[Greg Kroah-Hartman]

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>

commit ae7b8eda27b33b1f688dfdebe4d46f690a8f9162 upstream.

There is a potential NULL pointer dereference in case devm_kzalloc()
fails and returns NULL.

Fix this by adding a NULL check on *lookup*

This bug was detected with the help of Coccinelle.

Fixes: b2e63555592f ("i2c: gpio: Convert to use descriptors")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/mfd/sm501.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/mfd/sm501.c
+++ b/drivers/mfd/sm501.c
@@ -1145,6 +1145,9 @@ static int sm501_register_gpio_i2c_insta
 	lookup = devm_kzalloc(&pdev->dev,
 			      sizeof(*lookup) + 3 * sizeof(struct gpiod_lookup),
 			      GFP_KERNEL);
+	if (!lookup)
+		return -ENOMEM;
+
 	lookup->dev_id = "i2c-gpio";
 	if (iic->pin_sda < 32)
 		lookup->table[0].chip_label = "SM501-LOW";