On 02/19, Rafael J. Wysocki wrote: > > On Monday, 19 February 2007 21:23, Oleg Nesterov wrote: > > > > @@ -199,6 +189,10 @@ static void thaw_tasks(int thaw_user_spa > > > > > > do_each_thread(g, p) { > > > + if (freezer_should_skip(p)) > > > + cancel_freezing(p); > > > + } while_each_thread(g, p); > > > + do_each_thread(g, p) { > > > if (!freezeable(p)) > > > continue; > > > > Any reason for 2 separate do_each_thread() loops ? > > Yes. If there is a "freeze" request pending for the vfork parent (TIF_FREEZE > set), we have to cancel it before the child is unfrozen, since otherwise the > parent may go freezing after we try to reset PF_FROZEN for it.
I see, thanks... thaw_process() doesn't take TIF_FREEZE into account. But doesn't this mean we have a race? Suppose that try_to_freeze_tasks() failed. It does cancel_freezing() for each process before return, but what if some thread already checked TIF_FREEZE and (for simplicity) it is preempted before frozen_process() in refrigerator(). thaw_tasks() runs, ignores this task (P), returns. P gets CPU, and becomes frozen, but nobody will thaw it. No? Oleg. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/