ublk: fail to start device if queue setup is interrupted

BugLink: https://bugs.launchpad.net/bugs/2037005
[ Upstream commit 53e7d08f6d6e214c40db1f51291bb2975c789dc2 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Roxana Nicolescu <roxana.nicolescu@canonical.com>

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 3ae22e7eb0b09e8c2bf6aedeba4c40f7174c10ab..495e1bf9003b68594ad9c6e3cb01e25edd15616a 100644 (file)
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -1539,7 +1539,8 @@ 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);