[PATCH] slimbus: qcom-ngd: fix NULL pointer dereference in qcom_slim_ngd_xfer_msg()

[Anas Iqbal]

txn->msg is dereferenced without a prior NULL check in
qcom_slim_ngd_xfer_msg(), which may lead to a NULL pointer
dereference.

Although current callers initialize txn->msg, add a defensive
check to prevent potential crashes if a NULL pointer is passed.

Fixes: 917809e2280bb ("slimbus: ngd: Add qcom SLIMBus NGD driver")
Signed-off-by: Anas Iqbal <mohd.abd.6602@xxxxxxxxx>
---
 drivers/slimbus/qcom-ngd-ctrl.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/slimbus/qcom-ngd-ctrl.c b/drivers/slimbus/qcom-ngd-ctrl.c
index 9aa7218b4e8d..241f5e08b582 100644
--- a/drivers/slimbus/qcom-ngd-ctrl.c
+++ b/drivers/slimbus/qcom-ngd-ctrl.c
@@ -805,6 +805,9 @@ static int qcom_slim_ngd_xfer_msg(struct slim_controller *sctrl,
 	if (txn->dt == SLIM_MSG_DEST_ENUMADDR)
 		return -EPROTONOSUPPORT;
 
+	if (!txn->msg)
+		return -EINVAL;
+
 	if (txn->msg->num_bytes > SLIM_MSGQ_BUF_LEN ||
 			txn->rl > SLIM_MSGQ_BUF_LEN) {
 		dev_err(ctrl->dev, "msg exceeds HW limit\n");
-- 
2.43.0