Re: [PATCH v3 01/12] KVM: arm/arm64: Set dist->spis to NULL after kfree

Christoffer Dall
2018-04-24T21:06:33Z

On Fri, Apr 13, 2018 at 10:20:47AM +0200, Eric Auger wrote:
> in case kvm_vgic_map_resources() fails, typically if the vgic
> distributor is not defined, __kvm_vgic_destroy will be called
> several times. Indeed kvm_vgic_map_resources() is called on
> first vcpu run. As a result dist->spis is freeed more than once
> and on the second time it causes a "kernel BUG at mm/slub.c:3912!"
>
> Set dist->spis to NULL to avoid the crash.
>
> Fixes: ad275b8bb1e6 ("KVM: arm/arm64: vgic-new: vgic_init: implement
> vgic_init")
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>

Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>

>
> ---
>
> v2 -> v3:
> - added Marc's R-b and Fixed commit
> ---
> virt/kvm/arm/vgic/vgic-init.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
> index 68378fe..c52f03d 100644
> --- a/virt/kvm/arm/vgic/vgic-init.c
> +++ b/virt/kvm/arm/vgic/vgic-init.c
> @@ -308,6 +308,7 @@ static void kvm_vgic_dist_destroy(struct kvm *kvm)
> dist->initialized = false;
>
> kfree(dist->spis);
> + dist->spis = NULL;
> dist->nr_spis = 0;
>
> if (vgic_supports_direct_msis(kvm))
> --
> 2.5.5
>