Messages in this thread | | | Date | Sun, 18 Feb 2007 19:19:53 +0300 | From | Oleg Nesterov <> | Subject | Re: freezer problems |
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On 02/18, Rafael J. Wysocki wrote: > > On Sunday, 18 February 2007 15:52, Oleg Nesterov wrote: > > > > And now another problem: exec. de_thread() sleeps in TASK_UNINTERRUPTIBLE > > waiting for all sub-threads to die, and we have the same "deadlock" if > > one of them is frozen. This is nasty. Probably we can change the ->state > > to TASK_INTERRUPTIBLE and add try_to_freeze(), or play with the new PF_ > > flag, but I am not sure it is safe to freeze() the task which is deep > > in the exec() path. > > Hm, I haven't been aware of this case. > > Well, probably we can do something like in the patch that I've just sent: the > child that enters the refrigerator should know that the parent is > uninterruptible and will wait for it to exit. Thus it can either mark the > parent as frozen or just exit the refrigerator without freezing itself.
Sub-thread could already sleep in refrigerator when another thread does exec. So we have no choice but somehow freeze the execer. But again, I don't know if it is safe to freeze it here, at de_thread() stage. It is called from load_xxx_binary(), we may hold some important locks...
Oleg.
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