test_firmware: fix a memory leak with reqs buffer

Dan Carpenter spotted that test_fw_config->reqs will be leaked if
trigger_batched_requests_store() is called two or more times.
The same appears with trigger_batched_requests_async_store().

This bug wasn't trigger by the tests, but observed by Dan's visual
inspection of the code.

The recommended workaround was to return -EBUSY if test_fw_config->reqs
is already allocated.

Fixes: 7feebfa ("test_firmware: add support for request_firmware_into_buf")
Cc: Luis Chamberlain <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Russ Weight <[email protected]>
Cc: Tianfei Zhang <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Colin Ian King <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: [email protected]
Cc: [email protected] # v5.4
Suggested-by: Dan Carpenter <[email protected]>
Suggested-by: Takashi Iwai <[email protected]>
Signed-off-by: Mirsad Goran Todorovac <[email protected]>
Reviewed-by: Dan Carpenter <[email protected]>
Acked-by: Luis Chamberlain <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Mirsad Goran Todorovac

lib/test_firmware.c

@@ -913,6 +913,11 @@ static ssize_t trigger_batched_requests_store(struct device *dev,
 
 	mutex_lock(&test_fw_mutex);
 
+	if (test_fw_config->reqs) {
+		rc = -EBUSY;
+		goto out_bail;
+	}
+
 	test_fw_config->reqs =
 		vzalloc(array3_size(sizeof(struct test_batched_req),
 				    test_fw_config->num_requests, 2));
@@ -1011,6 +1016,11 @@ ssize_t trigger_batched_requests_async_store(struct device *dev,
 
 	mutex_lock(&test_fw_mutex);
 
+	if (test_fw_config->reqs) {
+		rc = -EBUSY;
+		goto out_bail;
+	}
+
 	test_fw_config->reqs =
 		vzalloc(array3_size(sizeof(struct test_batched_req),
 				    test_fw_config->num_requests, 2));