Messages in this thread |  | | Date | Tue, 4 Oct 2016 10:22:15 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [tip:sched/urgent] Revert "sched/core: Do not use smp_processor_id() with preempt enabled in smpboot_thread_fn()" |
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On Tue, 4 Oct 2016, tip-bot for Ingo Molnar wrote: > The original change widens a preempt-off section, to avoid a seemingly unsafe > smp_processor_id() use. > > During review I overlooked two facts: > > - The code to calls a non-trivial function callback: > > ht->park(td->cpu); > > ... which might (and does occasionally) sleep, triggering the warning. > > - More importantly, as pointed out by Peter Zijlstra, using > smp_processor_id() in that context is safe, if it's done from > a kernel thread that is pinned to a single CPU - which is the > case here. > > So revert to the original code that enables preemption sooner. > > Reported-by: kernel test robot <xiaolong.ye@intel.com> > Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
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