[PATCH] firmware: qcom: uefisecapp: Fix deadlock in qcuefi_acquire()

[Dan Carpenter]

If the __qcuefi pointer is not set, then in the original code, we would
hold onto the lock.  That means that if we tried to set it later, then
it would cause a deadlock.  Drop the lock on the error path.  That's
what all the callers are expecting.

Fixes: 759e7a2b62eb ("firmware: Add support for Qualcomm UEFI Secure Application")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
 drivers/firmware/qcom/qcom_qseecom_uefisecapp.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/firmware/qcom/qcom_qseecom_uefisecapp.c b/drivers/firmware/qcom/qcom_qseecom_uefisecapp.c
index 6fefa4fe80e8..447246bd04be 100644
--- a/drivers/firmware/qcom/qcom_qseecom_uefisecapp.c
+++ b/drivers/firmware/qcom/qcom_qseecom_uefisecapp.c
@@ -715,6 +715,10 @@ static int qcuefi_set_reference(struct qcuefi_client *qcuefi)
 static struct qcuefi_client *qcuefi_acquire(void)
 {
 	mutex_lock(&__qcuefi_lock);
+	if (!__qcuefi) {
+		mutex_unlock(&__qcuefi_lock);
+		return NULL;
+	}
 	return __qcuefi;
 }
 
-- 
2.45.2