And this discussion reminds me again that I do not understand how setns() and PR_SET_CHILD_SUBREAPER should play together... Add cc's.
Suppose we have a process P in the root namespace and another namespace X. P does setns() and enters the X namespace. P forks a child C. C forks a grandchild G. C exits. The question is, where should we reparent the grandchild G? In the normal case it will be reparented to X->child_reaper and this looks correct. But lets suppose that P runs with the ->has_child_subreaper bit set. In this case it will be reparented to P's sub-reaper or a global init, and given that P can't control its ->has_child_subreaper flag this does not look right to me. I can make a simple patch but perhaps I missed something or we actually want this (imo strange) behaviour? Oleg.
