Re: [PATCH v4 1/5] arm64: Add framework to turn IPI as NMI
From: Marc Zyngier <maz@kernel.org>
Date: 2020-10-10 22:59:11
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On Sat, 10 Oct 2020 02:58:55 +0100, Masayoshi Mizuma [off-list ref] wrote: [...]
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+void ipi_nmi_setup(int cpu) +{ + if (!ipi_desc) + return;ipi_nmi_setup() may be called twice for CPU0: set_smp_ipi_range => set_smp_ipi_nmi => ipi_nmi_setup => ipi_setup => ipi_nmi_setup Actually, I got the following error message via the second ipi_nmi_setup(): GICv3: Pseudo-NMIs enabled using relaxed ICC_PMR_EL1 synchronisation GICv3: Cannot set NMI property of enabled IRQ 8 genirq: Failed to setup NMI delivery: irq 8 Why don't we have a check to prevent that? Like as: if (cpumask_test_cpu(cpu, ipi_desc->percpu_enabled)) return;
That's definitely the wrong thing to do. prepare_nmi_setup() shouldn't be called twice, and papering over it isn't acceptable. M. -- Without deviation from the norm, progress is not possible. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel