s390/dasd: fix Oops in dasd_alias_get_start_dev due to missing pavgroup

[linux-stable] / drivers / s390 / block / dasd_alias.c

diff --git a/drivers/s390/block/dasd_alias.c b/drivers/s390/block/dasd_alias.c
index dc78a523a69f2104d911555b097a6407a8e04cc1..b6b938aa6615894087d20943624e60bac54754a8 100644 (file)
--- a/drivers/s390/block/dasd_alias.c
+++ b/drivers/s390/block/dasd_alias.c
@@ -675,12 +675,12 @@ int dasd_alias_remove_device(struct dasd_device *device)
 struct dasd_device *dasd_alias_get_start_dev(struct dasd_device *base_device)
 {
        struct dasd_eckd_private *alias_priv, *private = base_device->private;
-       struct alias_pav_group *group = private->pavgroup;
        struct alias_lcu *lcu = private->lcu;
        struct dasd_device *alias_device;
+       struct alias_pav_group *group;
        unsigned long flags;
 
-       if (!group || !lcu)
+       if (!lcu)
                return NULL;
        if (lcu->pav == NO_PAV ||
            lcu->flags & (NEED_UAC_UPDATE | UPDATE_PENDING))
@@ -697,6 +697,11 @@ struct dasd_device *dasd_alias_get_start_dev(struct dasd_device *base_device)
        }
 
        spin_lock_irqsave(&lcu->lock, flags);
+       group = private->pavgroup;
+       if (!group) {
+               spin_unlock_irqrestore(&lcu->lock, flags);
+               return NULL;
+       }
        alias_device = group->next;
        if (!alias_device) {
                if (list_empty(&group->aliaslist)) {