Hi all, while trying to plug a race in the CPU hotplug code on xAPIC systems, I was analyzing IPI transmission patterns. The handlers in arch/x86/include/asm/ipi.h first wait for ICR, then send. In contrast, arch_irq_work_raise sends the self-IPI directly and then waits. This looks inconsistent. Is it intended?
BTW, the races are in wakeup_secondary_cpu_via_init and wakeup_secondary_cpu_via_nmi (lacking IRQ disable around ICR accesses). There we also send first, then wait for completion. But I guess that is due to the code originally only being used during boot. Will send fixes for those once the sync pattern is clear to me. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SES-DE Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
