1 files changed, 18 insertions, 1 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 93b0da13350..f97c3b2f2f8 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -570,7 +570,7 @@ static void mddev_put(struct mddev *mddev)
             mddev->ctime == 0 && !mddev->hold_active) {
                 /* Array is not configured at all, and not held active,
                  * so destroy it */
-                list_del(&mddev->all_mddevs);
+                list_del_init(&mddev->all_mddevs);
                 bs = mddev->bio_set;
                 mddev->bio_set = NULL;
                 if (mddev->gendisk) {
@@ -4489,11 +4489,20 @@ md_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 
         if (!entry->show)
                 return -EIO;
+        spin_lock(&all_mddevs_lock);
+        if (list_empty(&mddev->all_mddevs)) {
+                spin_unlock(&all_mddevs_lock);
+                return -EBUSY;
+        }
+        mddev_get(mddev);
+        spin_unlock(&all_mddevs_lock);
+
         rv = mddev_lock(mddev);
         if (!rv) {
                 rv = entry->show(mddev, page);
                 mddev_unlock(mddev);
         }
+        mddev_put(mddev);
         return rv;
 }
 
@@ -4509,11 +4518,19 @@ md_attr_store(struct kobject *kobj, struct attribute *attr,
                 return -EIO;
         if (!capable(CAP_SYS_ADMIN))
                 return -EACCES;
+        spin_lock(&all_mddevs_lock);
+        if (list_empty(&mddev->all_mddevs)) {
+                spin_unlock(&all_mddevs_lock);
+                return -EBUSY;
+        }
+        mddev_get(mddev);
+        spin_unlock(&all_mddevs_lock);
         rv = mddev_lock(mddev);
         if (!rv) {
                 rv = entry->store(mddev, page, length);
                 mddev_unlock(mddev);
         }
+        mddev_put(mddev);
         return rv;
 }