Re: [PATCH] ublk_drv: fix NULL pointer dereference in ublk_ctrl_start_recovery()

[Li Nan <linan666@xxxxxxxxxxxxxxx>]

在 2024/6/3 8:39, Ming Lei 写道:

[...]

> > diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> > index 4e159948c912..99b621b2d40f 100644
> > --- a/drivers/block/ublk_drv.c
> > +++ b/drivers/block/ublk_drv.c
> > @@ -2630,7 +2630,8 @@ static void ublk_queue_reinit(struct ublk_device *ub, struct ublk_queue *ubq)
> >   {
> >   	int i;
> >   
> > -	WARN_ON_ONCE(!(ubq->ubq_daemon && ubq_daemon_is_dying(ubq)));
> > +	if (WARN_ON_ONCE(!(ubq->ubq_daemon && ubq_daemon_is_dying(ubq))))
> > +		return;
>
> Yeah, it is one bug. However, it could be addressed by adding the check in
> ublk_ctrl_start_recovery() and return immediately in case of NULL ubq->ubq_daemon,
> what do you think about this way?

Check ub->nr_queues_ready seems better. How about:

@@ -2662,6 +2662,8 @@ static int ublk_ctrl_start_recovery(struct 
ublk_device *ub,
        mutex_lock(&ub->mutex);
        if (!ublk_can_use_recovery(ub))
                goto out_unlock;
+       if (!ub->nr_queues_ready)
+               goto out_unlock;
        /*
         * START_RECOVERY is only allowd after:
         *

> Thanks,
> Ming

--
Thanks,
Nan