On Wed, Nov 30, 2022 at 09:21:54PM +0800, Li Nan wrote: > T1 T2 T3 > //delete device > del_gendisk > bdi_unregister > bdi_remove_from_list > synchronize_rcu_expedited > > //rmdir cgroup > blkcg_destroy_blkgs > blkg_destroy > percpu_ref_kill > blkg_release > call_rcu > rq_qos_exit > ioc_rqos_exit > kfree(ioc) > __blkg_release > blkg_free > blkg_free_workfn > pd_free_fn > ioc_pd_free > spin_lock_irqsave > ->ioc is freed > > Fix the problem by moving the operation on ioc in ioc_pd_free() to > ioc_pd_offline(), and just free resource in ioc_pd_free() like iolatency > and throttle. > > Signed-off-by: Li Nan <linan122@xxxxxxxxxx> I wonder what we really wanna do is pinning ioc while blkgs are still around but I think this should work too. Acked-by: Tejun Heo <tj@xxxxxxxxxx> Thanks. -- tejun
