ublk: fail to start device if queue setup is interrupted

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 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@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230726144502.566785-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 1c823750c95af139f92b7f8b9f5bdee309e5e02d..7938221f4f7e253091bdb6e0a6a087977226e629 100644 (file)
--- 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);