Commit 9cfcf99e authored by Li Lingfeng's avatar Li Lingfeng Committed by Song Liu
Browse files

md: get rdev->mddev with READ_ONCE() 



Users may get rdev->mddev by sysfs while rdev is releasing.
So use both READ_ONCE() and WRITE_ONCE() to prevent load/store tearing
and to read/write mddev atomically.

Signed-off-by: default avatarLi Lingfeng <lilingfeng3@huawei.com>
Reviewed-by: default avatarYu Kuai <yukuai3@huawei.com>
Signed-off-by: default avatarSong Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20231229070500.3602712-1-lilingfeng@huaweicloud.com
parent faeaf210

drivers/md/md.c

+2 −2
Original line number Diff line number Diff line
@@ -2591,7 +2591,7 @@ static void md_kick_rdev_from_array(struct md_rdev *rdev) 
	list_del_rcu(&rdev->same_set);

	pr_debug("md: unbind<%pg>\n", rdev->bdev);

	mddev_destroy_serial_pool(rdev->mddev, rdev);

	rdev->mddev = NULL;

	WRITE_ONCE(rdev->mddev, NULL);

	sysfs_remove_link(&rdev->kobj, "block");

	sysfs_put(rdev->sysfs_state);

	sysfs_put(rdev->sysfs_unack_badblocks);
@@ -3664,7 +3664,7 @@ rdev_attr_store(struct kobject *kobj, struct attribute *attr, 
	struct kernfs_node *kn = NULL;

	bool suspend = false;

	ssize_t rv;

	struct mddev *mddev = rdev->mddev;

	struct mddev *mddev = READ_ONCE(rdev->mddev);



	if (!entry->store)

		return -EIO;