In the Linux kernel, the following vulnerability has been resolved:s390/dasd: fix Oops in dasd_alias_get_start_dev due to missing pavgroupFix Oops in dasd_alias_get_start_dev() function caused by the pavgroup
pointer being NULL.The pavgroup pointer is checked on the entrance of the function but
without the lcu->lock being held. Therefore there is a race window
between dasd_alias_get_start_dev() and _lcu_update() which sets
pavgroup to NULL with the lcu->lock held.Fix by checking the pavgroup pointer with lcu->lock held.