2013-08-20 03:28:37

by Michael Neuling

Subject: [PATCH] kvm tools: powerpc: Fix init order for xics

xics_init() assumes kvm->nrcpus is already setup. kvm->nrcpus is setup
in kvm_cpu_init()

Unfortunately xics_init() and kvm_cpu_init() both use base_init(). So
depending on the order randomly determined by the compiler, xics_init()
may initialised see kvm->nrcpus as 0 and not setup any of the icp VCPU
pointers. This manifests itself later in boot when trying to raise an
IRQ resulting in a null pointer deference/segv.

This moves xics_init() to use dev_base_init() to ensure it happens after
kvm_cpu_init().

Signed-off-by: Michael Neuling <[email protected]>

diff --git a/tools/kvm/powerpc/xics.c b/tools/kvm/powerpc/xics.c
index cf64a08..c1ef35b 100644
--- a/tools/kvm/powerpc/xics.c
+++ b/tools/kvm/powerpc/xics.c
@@ -505,7 +505,7 @@ static int xics_init(struct kvm *kvm)

return 0;
}
-base_init(xics_init);
+dev_base_init(xics_init);


void kvm__irq_line(struct kvm *kvm, int irq, int level)

2013-08-27 11:52:36

by Pekka Enberg

Subject: Re: [PATCH] kvm tools: powerpc: Fix init order for xics

On Tue, Aug 20, 2013 at 6:28 AM, Michael Neuling <[email protected]> wrote:
> xics_init() assumes kvm->nrcpus is already setup. kvm->nrcpus is setup
> in kvm_cpu_init()
>
> Unfortunately xics_init() and kvm_cpu_init() both use base_init(). So
> depending on the order randomly determined by the compiler, xics_init()
> may initialised see kvm->nrcpus as 0 and not setup any of the icp VCPU
> pointers. This manifests itself later in boot when trying to raise an
> IRQ resulting in a null pointer deference/segv.
>
> This moves xics_init() to use dev_base_init() to ensure it happens after
> kvm_cpu_init().
>
> Signed-off-by: Michael Neuling <[email protected]>

Applied, thanks a lot!