On Mon, Nov 22, 2010 at 10:53:00AM +0100, Per Fransson wrote: > > > > I wonder whether it is good idea to enable interrupts here? What > > if we came here from an interrupt handler with interrupts already > > disabled? > > > > I guess you did this because smp_call_function() needs to have > > interrupts enabled, right? > > > > Yup, that's why I did it. > > > As we still need to make sure that all the secondary CPUs are > > stopped, should we do just something like: > > > > ? ? ? ?smp_send_stop(); > > > > and then in ipi_cpu_stop() we check whether oops_in_progress is set > > and save the cpu state before entering that never-ending loop? > > But we still need to wait for it to complete, right? Will smp_send_stop() > handle the requirements of the underlying ipi regardless of the initial state? In a crashing state, any kind of IPIs are not guaranteed. The other CPUs may be in an IRQ-protected region waiting for a lock which the crashing CPU already holds, and so the IPI won't be received. However, we do need smp_send_stop() to wait for a limited time for the other CPUs to respond to the request. We should also do something more intelligent than spinning in a while(1) loop.
