Re: [PATCH]broadcast IPI race condition on CPU hotplug

From: Li Shaohua
Date: Mon Apr 25 2005 - 23:32:41 EST


Hi,
On Tue, 2005-04-26 at 12:25, Zwane Mwaikambo wrote:
>
> > 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.
>
> Ok, but isn't it sufficient to use send_ipi_mask in smp_call_function
> instead?
I'm not sure if other routines using broadcast IPI have this bug. Fixing
the send_ipi_all API looks more generic. Is there any reason we should
use broadcast IPI?

Thanks,
Shaohua

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