On Wed, Aug 10, 2016 at 12:26 AM, Tejun Heo <tj@xxxxxxxxxx> wrote: > Hello, Balbir. > > On Tue, Aug 09, 2016 at 05:02:47PM +1000, Balbir Singh wrote: >> > Hmm? Where does mem_cgroup_iter grab cgroup_mutex? cgroup_mutex nests >> > outside cgroup_threadgroup_rwsem or most other mutexes for that matter >> > and isn't exposed from cgroup core. >> > >> >> I based my theory on the code >> >> mem_cgroup_iter -> css_next_descendant_pre which asserts >> >> cgroup_assert_mutex_or_rcu_locked(), >> >> although you are right, we hold RCU lock while calling css_* routines. > > That's "or". The iterator can be called either with RCU lock or > cgroup_mutex. cgroup core may use it under cgroup_mutex. Everyone > else uses it with rcu. > > Thanks. > Hi, Tejun Thanks agreed! Could you please consider queuing the fix after review. Balbir Singh. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>