alua_rtpg() can race with alua_bus_detach(). The assertion that
alua_dh_data *h->sdev must be non-NULL is not guaranteed because
alua_bus_detach sets this field to NULL before removing the entry
from the port group's dh_list.
This happens when a device is about to be removed, so don't BUG out
but continue silently.
Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
Reviewed-by: Hannes Reinecke <hare@xxxxxxxx>
---
drivers/scsi/device_handler/scsi_dh_alua.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 2b60f493f90e..a59783020c66 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -652,9 +652,15 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
rcu_read_lock();
list_for_each_entry_rcu(h,
&tmp_pg->dh_list, node) {
- /* h->sdev should always be valid */
- BUG_ON(!h->sdev);
- h->sdev->access_state = desc[0];
+ /*
+ * We might be racing with
+ * alua_bus_detach here
+ */
+ struct scsi_device *sdev =
+ h->sdev;
+ if (sdev)
+ sdev->access_state =
+ desc[0];
}
rcu_read_unlock();
}
@@ -694,11 +700,13 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
pg->expiry = 0;
rcu_read_lock();
list_for_each_entry_rcu(h, &pg->dh_list, node) {
- BUG_ON(!h->sdev);
- h->sdev->access_state =
+ struct scsi_device *sdev = h->sdev;
+ if (!sdev)
+ continue;
+ sdev->access_state =
(pg->state & SCSI_ACCESS_STATE_MASK);
if (pg->pref)
- h->sdev->access_state |=
+ sdev->access_state |=
SCSI_ACCESS_STATE_PREFERRED;
}
rcu_read_unlock();
--
2.12.2
