scsi: bsg: Fix device unregistration

device_initialize() is used to take a refcount on the device. However,
put_device() is not called during device teardown. This leads to a
leak of private data of the driver core, dev_name(), etc. This is
reported by kmemleak at boot time if we compile kernel with
DEBUG_TEST_DRIVER_REMOVE.

Fix memory leaks during unregistration and implement a release
function.

Link: https://lore.kernel.org/r/20210911105306.1511-1-yuzenghui@huawei.com
Fixes: ead09dd3aed5 ("scsi: bsg: Simplify device registration")
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/block/bsg.c b/block/bsg.c
index 3510951..882f56b 100644 (file)
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -165,13 +165,20 @@ static const struct file_operations bsg_fops = {
        .llseek         =       default_llseek,
 };
 
+static void bsg_device_release(struct device *dev)
+{
+       struct bsg_device *bd = container_of(dev, struct bsg_device, device);
+
+       ida_simple_remove(&bsg_minor_ida, MINOR(bd->device.devt));
+       kfree(bd);
+}
+
 void bsg_unregister_queue(struct bsg_device *bd)
 {
        if (bd->queue->kobj.sd)
                sysfs_remove_link(&bd->queue->kobj, "bsg");
        cdev_device_del(&bd->cdev, &bd->device);
-       ida_simple_remove(&bsg_minor_ida, MINOR(bd->device.devt));
-       kfree(bd);
+       put_device(&bd->device);
 }
 EXPORT_SYMBOL_GPL(bsg_unregister_queue);
 
@@ -193,11 +200,13 @@ struct bsg_device *bsg_register_queue(struct request_queue *q,
        if (ret < 0) {
                if (ret == -ENOSPC)
                        dev_err(parent, "bsg: too many bsg devices\n");
-               goto out_kfree;
+               kfree(bd);
+               return ERR_PTR(ret);
        }
        bd->device.devt = MKDEV(bsg_major, ret);
        bd->device.class = bsg_class;
        bd->device.parent = parent;
+       bd->device.release = bsg_device_release;
        dev_set_name(&bd->device, "%s", name);
        device_initialize(&bd->device);
 
@@ -205,7 +214,7 @@ struct bsg_device *bsg_register_queue(struct request_queue *q,
        bd->cdev.owner = THIS_MODULE;
        ret = cdev_device_add(&bd->cdev, &bd->device);
        if (ret)
-               goto out_ida_remove;
+               goto out_put_device;
 
        if (q->kobj.sd) {
                ret = sysfs_create_link(&q->kobj, &bd->device.kobj, "bsg");
@@ -217,10 +226,8 @@ struct bsg_device *bsg_register_queue(struct request_queue *q,
 
 out_device_del:
        cdev_device_del(&bd->cdev, &bd->device);
-out_ida_remove:
-       ida_simple_remove(&bsg_minor_ida, MINOR(bd->device.devt));
-out_kfree:
-       kfree(bd);
+out_put_device:
+       put_device(&bd->device);
        return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(bsg_register_queue);