On Sat, Jul 30, 2016 at 7:25 PM, Heiko Carstens <heiko.carst...@de.ibm.com> wrote: > On Wed, Jul 27, 2016 at 05:23:05PM +0200, Thomas Gleixner wrote: >> On Wed, 27 Jul 2016, Heiko Carstens wrote: >> > [ 3.162961] ([<0000000000176c30>] select_task_rq+0xc0/0x1a8) >> > [ 3.162963] ([<0000000000177d64>] try_to_wake_up+0x2e4/0x478) >> > [ 3.162968] ([<000000000015d46c>] create_worker+0x174/0x1c0) >> > [ 3.162971] ([<0000000000161a98>] alloc_unbound_pwq+0x360/0x438) >> >> > For some unknown reason select_task_rq() gets called with a task that has >> > nr_cpus_allowed == 0. Hence "cpu = cpumask_any(tsk_cpus_allowed(p));" >> > within select_task_rq() will set cpu to nr_cpu_ids which in turn causes the >> > warning later on. >> > >> > It only happens with more than one node, otherwise it seems to work fine. >> > >> > Any idea what could be wrong here? >> >> create_worker() >> tsk = kthread_create_on_node(); >> kthread_bind_mask(tsk, pool->attrs->cpumask); >> do_set_cpus_allowed(tsk, mask); >> set_cpus_allowed_common(tsk, mask); >> cpumask_copy(&tsk->cpus_allowed, mask); >> tsk->nr_cpus_allowed = cpumask_weight(mask); >> wake_up_process(task); >> >> So this looks like pool->attrs->cpumask is simply empty..... > > Just had some time to look into this a bit more. Looks like we initialize > the cpu_to_node_masks (way) too late on s390 for fake numa. So Peter's > patch just revealed that problem. > > I'll see if initializing the masks earlier will fix this, but I think it > will.
Hello, Is there any fix for this issue? I can see the issue on arm64 running v4.7 kernel too. And the oops can be avoided by reverting commit e9d867a(sched: Allow per-cpu kernel threads to run on online && !active). Thanks, Ming Lei
