[PATCH v2] staging: gpib: Fix memory leak in ni_usb_init()

[Zilin Guan]

In ni_usb_init(), if ni_usb_setup_init() fails, the function returns
immediately without freeing the allocated memory for writes, leading
to a memory leak.

Fix this by freeing writes before returning the error code.

Fixes: 4e127de14fa7 ("staging: gpib: Add National Instruments USB GPIB driver")
Suggested-by: Dave Penkler <dpenkler@xxxxxxxxx>
Co-developed-by: Jianhao Xu <jianhao.xu@xxxxxxxxxx>
Signed-off-by: Jianhao Xu <jianhao.xu@xxxxxxxxxx>
Signed-off-by: Zilin Guan <zilin@xxxxxxxxxx>
---
Changes in v2:
- Use early return to simplify error handling logic.

 drivers/gpib/ni_usb/ni_usb_gpib.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpib/ni_usb/ni_usb_gpib.c b/drivers/gpib/ni_usb/ni_usb_gpib.c
index 1f8412de9fa3..2352c6817440 100644
--- a/drivers/gpib/ni_usb/ni_usb_gpib.c
+++ b/drivers/gpib/ni_usb/ni_usb_gpib.c
@@ -1799,10 +1799,12 @@ static int ni_usb_init(struct gpib_board *board)
 		return -ENOMEM;
 
 	writes_len = ni_usb_setup_init(board, writes);
-	if (writes_len)
-		retval = ni_usb_write_registers(ni_priv, writes, writes_len, &ibsta);
-	else
+	if (!writes_len) {
+		kfree(writes);
 		return -EFAULT;
+	}
+
+	retval = ni_usb_write_registers(ni_priv, writes, writes_len, &ibsta);
 	kfree(writes);
 	if (retval) {
 		dev_err(&usb_dev->dev, "register write failed, retval=%i\n", retval);
-- 
2.34.1