On Tue, Jan 21, 2014 at 02:02:06PM +0100, Jan Kiszka wrote: > 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.
Could be I had no clue what I was doing and copy/pasted the code until it compiled and ran. In fact, I've got no clue what an ICR is. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
