Hello all, It looks like I sent this email to the wrong mailing list according to RedHat so I am sending it here: >From my earlier post: https://www.redhat.com/archives/dm-devel/2020-September/msg00083.html Would it be better to move the unsetting the address of sdev to NULL lower? This would protect against the crash we see when the alua_rtpg function tries to access the sdev address that has been set to NULL in alua_bus_detach by another thread. --- a/linux-5.4.17/drivers/scsi/device_handler/scsi_dh_alua.c 2020-07-29 22:48:30.000000000 -0600 +++ b/linux-5.4.17/drivers/scsi/device_handler/scsi_dh_alua.c 2020-09-07 13:38:23.771575702 -0600 @@ -1146,15 +1146,15 @@ spin_lock(&h->pg_lock); pg = rcu_dereference_protected(h->pg, lockdep_is_held(&h->pg_lock)); - rcu_assign_pointer(h->pg, NULL); - h->sdev = NULL; - spin_unlock(&h->pg_lock); if (pg) { spin_lock_irq(&pg->lock); list_del_rcu(&h->node); spin_unlock_irq(&pg->lock); kref_put(&pg->kref, release_port_group); } + rcu_assign_pointer(h->pg, NULL); + h->sdev = NULL; + spin_unlock(&h->pg_lock); sdev->handler_data = NULL; kfree(h); } Thanks, Brian Brian Bunker SW Eng brian@xxxxxxxxxxxxxxx
