Messages in this thread | | | Subject | Re: [RFC 01/12] KVM: arm/arm64: Avoid multiple dist->spis kfree | From | Marc Zyngier <> | Date | Mon, 19 Mar 2018 13:46:15 +0000 |
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On 19/03/18 09:20, 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 twice and on > the second time it causes a "kernel BUG at mm/slub.c:3912!" > > This patch avoids freeing dist->spis twice. > > Signed-off-by: Eric Auger <eric.auger@redhat.com> > --- > virt/kvm/arm/vgic/vgic-init.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c > index 743ca5c..38fd5f1 100644 > --- a/virt/kvm/arm/vgic/vgic-init.c > +++ b/virt/kvm/arm/vgic/vgic-init.c > @@ -324,7 +324,10 @@ static void kvm_vgic_dist_destroy(struct kvm *kvm) > dist->ready = false; > dist->initialized = false; > > - kfree(dist->spis); > + if (dist->spis) { > + kfree(dist->spis); > + dist->spis = NULL; > + }
Given that kfree(NULL) is always a valid thing to do, you could write the same thing just as
dist-> spis = NULL;
without any test.
> dist->nr_spis = 0; > > if (vgic_supports_direct_msis(kvm)) >
You also may want to add a Fixes tag to it.
Thanks,
M. -- Jazz is not dead. It just smells funny...
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