In ublk_ctrl_start_dev(), if wait_for_completion_interruptible() is interrupted by signal, queues aren't setup successfully yet, so we have to fail UBLK_CMD_START_DEV, otherwise kernel oops can be triggered. Reported by German when working for supporting ublk on qemu-storage-deamon which requires single thread ublk daemon. Fixes: 71f28f3136af ("ublk_drv: add io_uring based userspace block driver") Reported-by: German Maglione <gmaglione@xxxxxxxxxx> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> --- drivers/block/ublk_drv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 1c823750c95a..7938221f4f7e 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -1847,7 +1847,8 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd) if (ublksrv_pid <= 0) return -EINVAL; - wait_for_completion_interruptible(&ub->completion); + if (wait_for_completion_interruptible(&ub->completion) != 0) + return -EINTR; schedule_delayed_work(&ub->monitor_work, UBLK_DAEMON_MONITOR_PERIOD); -- 2.40.1