On Wed, Jul 24, 2013 at 11:56:18AM -0700, Stephen Boyd wrote: > On 07/09, Stephen Boyd wrote: > > If one process calls sys_reboot and that process then stops other > > CPUs while those CPUs are within a spin_lock() region we can > > potentially encounter a deadlock scenario like below. > > > > CPU 0 CPU 1 > > ----- ----- > > spin_lock(my_lock) > > smp_send_stop() > > <send IPI> handle_IPI() > > disable_preemption/irqs > > while(1); > > <PREEMPT> > > spin_lock(my_lock) <--- Waits forever > > > > We shouldn't attempt to run any other tasks after we send a stop > > IPI to a CPU so disable preemption so that this task runs to > > completion. > > > > Reported-by: Sundarajan Srinivasan <sunda...@codeaurora.com> > > Signed-off-by: Stephen Boyd <sb...@codeaurora.org> > > --- > > > > Resending this patch now that the context has changed. > > Ping? Shall I put this in the patch tracker?
Well, looking at x86, they use local_irq_disable() before sending the stop, so I think we should do the same for cross-arch consistency. -- 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/
