On 01/04, Mandeep Singh Baines wrote: > > Oleg Nesterov (oleg@xxxxxxxxxx) wrote: > > On 12/21, Frederic Weisbecker wrote: > > > > > > On Wed, Dec 21, 2011 at 11:24:13AM -0800, Mandeep Singh Baines wrote: > > > > > > > > If you call exec from a thread other than g, g is now unlinked. So > > > > "t != g" will always be true. If you then pthread_create, you now > > > > have two threads so "t != __prev" will also always be true. So > > > > you now have an infinite loop. > > > > > > Oh you're right. > > > > > > But then we can't use t != t->group_leader because that assumes while_each_thread() > > > started on the leader. > > > > Yes, this can't work. > > > > Besides, we need more burriers to rely on the ->group_leader check. > > > > See http://marc.info/?t=127688987300002 > > > > I went through the thread. Were there any other concerns other than > requiring that you start with the group_leader and the barrier? > > You could modify zap_other_threads to start with the group leader by > skipping p: > > if (p == t) > continue; Yes, we can but there are other while_each_thread(nonleader) users. Yes we can fix them too but this looks a bit ugly and we need to change while_each_thread() anyway. And I do not see why this change will be simpler if we restrict it to group_leader. And note that zap_other_threads() is fine in any case, it is called under ->siglock. > > in particular, http://marc.info/?l=linux-kernel&m=127714242731448 > > I think this should work, but then we should do something with the > > users like zap_threads(). > > > > With that patch, won't you potentially miss the exec thread if an exec > occurs while you're iterating over the list? Is that OK? Of course it is not OK ;) Note the "we should do something with" above. Oleg. _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
