Messages in this thread | | | From | (Eric W. Biederman) | Subject | Re: [patch] genirq/MSI: restore __do_IRQ() compat logic temporarily | Date | Tue, 12 Sep 2006 08:37:42 -0600 |
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Ingo Molnar <mingo@elte.hu> writes:
> * Eric W. Biederman <ebiederm@xmission.com> wrote: > >> Ok. Looking at it I almost certain the problem is that >> we lost the hunk of code removed in: 266f0566761cf88906d634727b3d9fc2556f5cbd >> i386: Fix stack switching in do_IRQ >> >> - if (!irq_desc[irq].handle_irq) { >> - __do_IRQ(irq, regs); >> - goto out_exit; >> - } >> >> The msi code does not yet set desc->handle_irq. So when we attempt to >> call it we get a NULL pointer dereference. > > indeed ... We thought the MSI cleanup went all the way with the irqchips > conversion, that's we suggested to Andrew to drop this chunk in -mm too.
Sorry. At the time I was trying for a minimal fix to much more fundamental brain damage.
>> Except for adding that hunk back in and breaking 4K stacks I don't >> have an immediate fix. > > i've attached a bandaid patch for -mm below. Brandon, does this solve > the crash you are seeing? > >> I do have a pending cleanup that should result in us setting >> handle_irq in all cases. I will see if I can advance that shortly. > > yeah, that's the right solution.
The core problem at the moment is that the generic code in msi.c still knows about apics. So struct irq_chip needs to be pushed to the individual architectures. At which point it becomes easy to ensure we have a proper handle_irq value as we aren't trying to be impossibly generic.
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