At Mon, 16 Apr 2007 14:45:59 +0400, Oleg Nesterov wrote: > > On 04/16, Satoru Takeuchi wrote: > > > > --- linux-2.6.21-rc6-mm1.tsfix.orig/kernel/exit.c 2007-04-15 > > 16:56:12.000000000 +0900 > > +++ linux-2.6.21-rc6-mm1.tsfix/kernel/exit.c 2007-04-15 > > 16:56:17.000000000 +0900 > > @@ -680,10 +680,14 @@ > > reaper = child_reaper(father); > > break; > > } > > + if (reaper->time_slice_reaper == father) > > + reaper->time_slice_reaper = NULL; > > } while (reaper->exit_state); > > > > list_for_each_safe(_p, _n, &father->children) { > > p = list_entry(_p, struct task_struct, sibling); > > + if (p->time_slice_reaper == father) > > + p->time_slice_reaper = NULL; > > choose_new_parent(p, reaper); > > reparent_thread(p, father); > > } > > Index: linux-2.6.21-rc6-mm1.tsfix/kernel/sched.c > > =================================================================== > > --- linux-2.6.21-rc6-mm1.tsfix.orig/kernel/sched.c 2007-04-15 > > 16:56:12.000000000 +0900 > > +++ linux-2.6.21-rc6-mm1.tsfix/kernel/sched.c 2007-04-15 > > 16:56:17.000000000 +0900 > > @@ -1693,7 +1693,7 @@ > > * The remainder of the first timeslice might be recovered by > > * the parent if the child exits early enough. > > */ > > - p->first_time_slice = 1; > > + p->time_slice_reaper = current; > > p->timestamp = sched_clock(); > > local_irq_enable(); > > I am afraid this doesn't work for CLONE_THREAD. Suppose that some sub-thread > (not > main thread) T1 creates another sub-thread, T2. > > T2->time_slice_reaper = T1. > > then T1 exits, but forget_original_parent(T1) doesn't change > T2->time_slice_reaper, > because T2 is not on T1->children list. Now T2->time_slice_reaper points to an > already freed task_struct.
I intended that CLONE_THREAD case is managed on the do-while loop seeking `reaper'. However, anyway, my patch has a bug. On T1 exiting, if there are any living threads ahead of T2, T2->time_slice_reaper isn't checked. What a easy mistake ... sorry. I'll post fixed version soon. Satoru - 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/