Hi Russell, On May 24, 2012, at 7:17 PM, Russell King - ARM Linux wrote:
> On Thu, May 24, 2012 at 07:50:24PM +0000, Pantelis Antoniou wrote: >> omap2plus_defconfig builds with SMP & SMP_ON_UP set. >> On beagle (which is UP) is_smp() returns false and we don't call >> smp_init_cpus which in turn does not initialize smp_cross_call which >> remains NULL. >> >> When issuing a reboot we OOPS with a NULL dereference on stop smp_call. > > I've been wondering whether we should make smp_cross_call() a no-op instead > by default, rather than a NULL pointer. > > Alternatively, if may be well worth changing this to do: > > if (!cpumask_empty(&mask)) > smp_cross_call(&mask, IPI_CPU_STOP); > > instead, so we avoid calling smp_cross_call() when we're on a SMP system > with only one CPU online. I like this approach better because it removes > a potential call into platform code which is inappropriate. Both of these can work, and in fact have been tried. I am partial on both to be honest. Have a default no-op function for smp_cross_call() and guard with cpumask_empty(). Which do you want me to make a patch for? Regards -- Pantelis -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
