On Mon, May 20, 2013 at 02:37:43PM +0200, Heiko Carstens wrote: > I just got a dump from a system running a 3.0.something kernel, however I > think the problem exists with current kernels as well. > > Testcase was some I/O intense workload together with cpu hotplug stress. > > When trying to bring a cpu online we got an endless loop on the cpu that > issued the cpu_up and called smp_call_function_single() within its cpu > hotplug notifier:
[...] > It looks to me like the IPI(s) was lost when cpu 3 was brought down before: [...] > So it looks to me like yet another CPU_DYING cpu hotplug notifier is needed > for the generic smp code, which looks for pending IPIs on the to be brought > down cpu and executes them. > > Does that make sense? Ok, I was able to reproduce it. And the fix should be in the s390 specific arch code within __cpu_disable() just before the cpu gets removed from the cpu online mask. No idea why this never has been seen before. -- 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/
