Messages in this thread | | | Date | Mon, 22 Jul 2019 20:37:19 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH v3 1/9] smp: Run functions concurrently in smp_call_function_many() |
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On Mon, 22 Jul 2019, Peter Zijlstra wrote:
> On Thu, Jul 18, 2019 at 05:58:29PM -0700, Nadav Amit wrote: > > +/* > > + * Call a function on all processors. May be used during early boot while > > + * early_boot_irqs_disabled is set. > > + */ > > +static inline void on_each_cpu(smp_call_func_t func, void *info, int wait) > > +{ > > + on_each_cpu_mask(cpu_online_mask, func, info, wait); > > +} > > I'm thinking that one if buggy, nothing protects online mask here.
The current implementation has preemption disabled before touching cpu_online_mask which at least protects against a CPU going away as that prevents the stomp machine thread from getting on the CPU. But it's not protected against a CPU coming online concurrently.
Thanks,
tglx
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