Messages in this thread | | | Date | Sun, 14 Aug 2011 19:51:19 +0200 | From | Oleg Nesterov <> | Subject | Re: Possible race between cgroup_attach_proc and de_thread, and questionable code in de_thread. |
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On 07/28, Paul E. McKenney wrote: > > On Thu, Jul 28, 2011 at 11:08:13AM +1000, NeilBrown wrote: > > > > I disagree. It also requires - by virtue of the use of while_each_thread() - > > that 'g' remains on the list that 't' is walking along. > > Doesn't the following code in the loop body deal with this possibilty? > > /* Exit if t or g was unhashed during refresh. */ > if (t->state == TASK_DEAD || g->state == TASK_DEAD) > goto unlock;
This code is completely wrong even if while_each_thread() was fine.
I sent the patch but it was ignored.
[PATCH] fix the racy check_hung_uninterruptible_tasks()->rcu_lock_break() http://marc.info/?l=linux-kernel&m=127688790019041
Oleg.
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