Igor Mammedov <[email protected]> writes: > Hang is observed on virtual machines during CPU hotplug, > especially in big guests with many CPUs. (It reproducible > more often if host is over-committed). > > It happens because master CPU gives up waiting on > secondary CPU and allows it to run wild. As result > AP causes locking or crashing system. For example > as described here: https://lkml.org/lkml/2014/3/6/257 > > If master CPU have sent STARTUP IPI successfully, > make it wait indefinitely till AP boots.
But what happens on a real machine when the other CPU is dead? I've seen that. Kernel still boots. With your patch it would hang. I don't think you can do that. It needs to have some timeout. Maybe a longer or configurable one? -Andi -- [email protected] -- Speaking for myself only -- 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/
