Messages in this thread | | | Date | Mon, 16 Apr 2007 14:45:59 +0400 | From | Oleg Nesterov <> | Subject | Re: [PATCH -mm] scheduler: fix the return of the first time_slice |
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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.
Oleg.
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