sched/x86/smp: Do not enable IRQs over calibrate_delay()
We should not ever enable IRQs until we're fully set up. This opens up a window where interrupts can hit the cpu and interrupts can do wakeups, wakeups need state that isn't set-up yet, in particular this cpu isn't elegible to run tasks, so if any cpu-affine task that got created in CPU_UP_PREPARE manages to get a wakeup, its affinity mask will get broken and we'll run into lots of 'interesting' problems. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-yaezmlbriluh166tfkgni22m@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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@ -219,14 +219,9 @@ static void __cpuinit smp_callin(void)
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* Update loops_per_jiffy in cpu_data. Previous call to
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* Update loops_per_jiffy in cpu_data. Previous call to
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* smp_store_cpu_info() stored a value that is close but not as
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* smp_store_cpu_info() stored a value that is close but not as
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* accurate as the value just calculated.
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* accurate as the value just calculated.
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*
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* Need to enable IRQs because it can take longer and then
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* the NMI watchdog might kill us.
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*/
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*/
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local_irq_enable();
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calibrate_delay();
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calibrate_delay();
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cpu_data(cpuid).loops_per_jiffy = loops_per_jiffy;
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cpu_data(cpuid).loops_per_jiffy = loops_per_jiffy;
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local_irq_disable();
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pr_debug("Stack at about %p\n", &cpuid);
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pr_debug("Stack at about %p\n", &cpuid);
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/*
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/*
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