In the Linux kernel, the following vulnerability has been resolved:
ublk_drv: fix NULL pointer dereference in ublk_ctrl_start_recovery()
When two UBLK_CMD_START_USER_RECOVERY commands are submitted, the
first one sets 'ubq->ubq_daemon' to NULL, and the second one triggers
WARN in ublk_queue_reinit() and subsequently a NULL pointer dereference
issue.
Fix it by adding the check in ublk_ctrl_start_recovery() and return
immediately in case of zero 'ub->nr_queues_ready'.
BUG: kernel NULL pointer dereference, address: 0000000000000028
RIP: 0010:ublk_ctrl_start_recovery.constprop.0+0x82/0x180
Call Trace:
CWE-476