Messages in this thread | | | Date | Wed, 22 Nov 2023 06:03:58 -1000 | From | Tejun Heo <> | Subject | Re: [PATCH] workqueue: Make sure that wq_unbound_cpumask is never empty |
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On Tue, Nov 21, 2023 at 11:39:36AM -1000, Tejun Heo wrote: > During boot, depending on how the housekeeping and workqueue.unbound_cpus > masks are set, wq_unbound_cpumask can end up empty. Since 8639ecebc9b1 > ("workqueue: Implement non-strict affinity scope for unbound workqueues"), > this may end up feeding -1 as a CPU number into scheduler leading to oopses. > > BUG: unable to handle page fault for address: ffffffff8305e9c0 > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > ... > Call Trace: > <TASK> > select_idle_sibling+0x79/0xaf0 > select_task_rq_fair+0x1cb/0x7b0 > try_to_wake_up+0x29c/0x5c0 > wake_up_process+0x19/0x20 > kick_pool+0x5e/0xb0 > __queue_work+0x119/0x430 > queue_work_on+0x29/0x30 > ... > > An empty wq_unbound_cpumask is a clear misconfiguration and already > disallowed once system is booted up. Let's warn on and ignore > unbound_cpumask restrictions which lead to no unbound cpus. While at it, > also remove now unncessary empty check on wq_unbound_cpumask in > wq_select_unbound_cpu(). > > Signed-off-by: Tejun Heo <tj@kernel.org> > Reported-by: Yong He <alexyonghe@tencent.com> > Link: http://lkml.kernel.org/r/20231120121623.119780-1-alexyonghe@tencent.com > Fixes: 8639ecebc9b1 ("workqueue: Implement non-strict affinity scope for unbound workqueues") > Cc: stable@vger.kernel.org # v6.6+
Applied to wq/for-6.7-fixes.
Thanks.
-- tejun
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