Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1501241
| From | Balbir Singh <bsingharora@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: Oops on Power8 (was Re: [PATCH v2 1/7] workqueue: make workqueue available early during boot) |
| Date | 2016-10-15 03:30 +0200 |
| Message-ID | <sslXr-Hv-1@gated-at.bofh.it> (permalink) |
| References | (2 earlier) <sirB7-5py-13@gated-at.bofh.it> <sqGMF-zG-9@gated-at.bofh.it> <sqIv7-1FC-5@gated-at.bofh.it> <sr3pT-666-15@gated-at.bofh.it> <sschr-2Xb-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 15/10/16 02:07, Tejun Heo wrote: > Hello, Michael. > > On Tue, Oct 11, 2016 at 10:22:13PM +1100, Michael Ellerman wrote: >> The oops happens because we're in enqueue_task_fair() and p->se->cfs_rq >> is NULL. >> >> The cfs_rq is NULL because we did set_task_rq(p, 2048), where 2048 is >> NR_CPUS. That causes us to index past the end of the tg->cfs_rq array in >> set_task_rq() and happen to get NULL. >> >> We never should have done set_task_rq(p, 2048), because 2048 is >= >> nr_cpu_ids, which means it's not a valid CPU number, and set_task_rq() >> doesn't cope with that. > > Hmm... it doesn't reproduce it here and can't see how the commit would > affect this given that it doesn't really change when the kworker > kthreads are being created. > >> Presumably we shouldn't be ending up with tsk_cpus_allowed() being >> empty, but I haven't had time to track down why that's happening. > I think the basic analysis shows the change to creation of unbounded workqueues from the unbound_hash, but those have a pool cpumask empty. > Can you please add WARN_ON_ONCE(!tsk_nr_cpus_allowed(p)) to > select_task_rq() and post what that says? > > Thanks. > Balbir Singh.
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Re: Oops on Power8 (was Re: [PATCH v2 1/7] workqueue: make workqueue available early during boot) Tejun Heo <tj@kernel.org> - 2016-10-14 17:10 +0200
Re: Oops on Power8 (was Re: [PATCH v2 1/7] workqueue: make workqueue available early during boot) Balbir Singh <bsingharora@gmail.com> - 2016-10-15 03:30 +0200
Re: Oops on Power8 (was Re: [PATCH v2 1/7] workqueue: make workqueue available early during boot) Michael Ellerman <mpe@ellerman.id.au> - 2016-10-15 11:50 +0200
Re: Oops on Power8 (was Re: [PATCH v2 1/7] workqueue: make workqueue available early during boot) Tejun Heo <tj@kernel.org> - 2016-10-17 20:20 +0200
Re: Oops on Power8 (was Re: [PATCH v2 1/7] workqueue: make workqueue available early during boot) Michael Ellerman <mpe@ellerman.id.au> - 2016-10-17 14:30 +0200
Re: Oops on Power8 (was Re: [PATCH v2 1/7] workqueue: make workqueue available early during boot) Balbir Singh <bsingharora@gmail.com> - 2016-10-17 15:00 +0200
Re: Oops on Power8 (was Re: [PATCH v2 1/7] workqueue: make workqueue available early during boot) Michael Ellerman <mpe@ellerman.id.au> - 2016-10-18 04:40 +0200
Re: Oops on Power8 (was Re: [PATCH v2 1/7] workqueue: make workqueue available early during boot) Tejun Heo <tj@kernel.org> - 2016-10-17 20:20 +0200
Re: Oops on Power8 (was Re: [PATCH v2 1/7] workqueue: make workqueue available early during boot) Tejun Heo <tj@kernel.org> - 2016-10-17 21:40 +0200
Re: Oops on Power8 (was Re: [PATCH v2 1/7] workqueue: make workqueue available early during boot) Tejun Heo <tj@kernel.org> - 2016-10-18 21:10 +0200
Re: Oops on Power8 (was Re: [PATCH v2 1/7] workqueue: make workqueue available early during boot) Michael Ellerman <mpe@ellerman.id.au> - 2016-10-19 17:00 +0200
[PATCH wq/for-4.10] workqueue: move wq_numa_init() to workqueue_init() Tejun Heo <tj@kernel.org> - 2016-10-19 18:20 +0200
csiph-web