2012/10/18 Tejun Heo <tj@xxxxxxxxxx>: > Hello, Frederic. > > On Thu, Oct 18, 2012 at 04:50:59PM +0200, Frederic Weisbecker wrote: >> Ah right I was confused. Hmm, indeed we have a race here on >> cgroup_fork(). How about using css_try_get() in cgroup_fork() and >> refetch the parent's css until we succeed? This requires rcu_read_lock >> though, and freeing the css_set under RCU. >> >> Don't know which is better. > > For now, I'll revert the patches and cc stable. Let's think about > improving it later. Ok for reverting in cgroup_fork(). Is it necessary for the cgroup_post_fork() thing? I don't immediately see any race involved there. >> Different problem but I really would like we sanitize the cgroup hooks >> in fork. There is cgroup_fork(), cgroup_post_fork() which takes that >> big css_set_lock, plus the big threadgroup lock... I hope we can >> simplify the mess there. > > Oh yeah, I've been looking at that one too. There are a few problems > in that area. I think all we need is clearing ->cgroups to NULL on > copy_process() and all the rest can be moved to cgroup_post_fork(). > I'd also like to make it very explicit that migration can't happen > before post_fork is complete. Sounds right. > >> > I really don't know. Why isn't it locking the threadgroup to begin >> > with? >> >> No idea, sounds like something to fix. > > Alrighty. Ok thanks. > Thanks. > > -- > tejun _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
