On Wed, Jul 26, 2023 at 03:30:34PM +0200, Stefano Garzarella wrote:
> On Wed, Jul 26, 2023 at 07:39:01PM +0800, Ming Lei wrote:
> > 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;
>
> Should we do somenthig similar also in ublk_ctrl_end_recovery()?
Good catch, ublk_ctrl_end_recovery() do need similar handling, otherwise
similar kernel oops may be triggered too.
>
> Maybe also in ublk_ctrl_del_dev() we can return -EINTR.
It doesn't matter for ublk_ctrl_del_dev() given it just waits for
existed users, but still good to return -EINTR to user.
Thanks,
Ming
