Messages in this thread | | | Subject | Re: [PATCH]broadcast IPI race condition on CPU hotplug | From | Li Shaohua <> | Date | Wed, 27 Apr 2005 09:11:59 +0800 |
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On Tue, 2005-04-26 at 21:21, Andi Kleen wrote: > On Tue, Apr 26, 2005 at 10:20:44AM +0800, Li Shaohua wrote: > > Hi, > > After a CPU is booted but before it's officially up (set online map, and > > enable interrupt), the CPU possibly will receive a broadcast IPI. After > > it's up, it will handle the stale interrupt soon and maybe cause oops if > > it's a smp-call-function-interrupt. This is quite possible in CPU > > hotplug case, but nearly can't occur at boot time. Below patch replaces > > broadcast IPI with send_ipi_mask just like the cluster mode. > > No way we are making this common operation much slower just > to fix an obscure race at boot time. PLease come up with a fix > that only impacts the boot process. We can't prevent a CPU to receive a broadcast interrupt. Ack the interrupt and mark the cpu online can't be atomic operation, so the CPU either receives unexpected interrupt or loses interrupt.
Thanks, Shaohua
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