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

From: Li Nan
Date: Sun Jun 02 2024 - 22:20:18 EST




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