| Message ID | 1484237774-19047-1-git-send-email-marc.zyngier@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Jan 12, 2017 at 04:16:14PM +0000, Marc Zyngier wrote: > Dmitry Vyukov reported that the syzkaller fuzzer triggered a > deadlock in the vgic setup code when an error was detected, as > the cleanup code tries to take a lock that is already held by > the setup code. > > The fix is to avoid retaking the lock when cleaning up, by > telling the cleanup function that we already hold it. > > Cc: stable@vger.kernel.org > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> > --- > virt/kvm/arm/vgic/vgic-init.c | 18 +++++++++++++----- > virt/kvm/arm/vgic/vgic-v2.c | 2 -- > virt/kvm/arm/vgic/vgic-v3.c | 2 -- > 3 files changed, 13 insertions(+), 9 deletions(-) > > diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c > index 5114391..c737ea0 100644 > --- a/virt/kvm/arm/vgic/vgic-init.c > +++ b/virt/kvm/arm/vgic/vgic-init.c > @@ -268,15 +268,11 @@ static void kvm_vgic_dist_destroy(struct kvm *kvm) > { > struct vgic_dist *dist = &kvm->arch.vgic; > > - mutex_lock(&kvm->lock); > - > dist->ready = false; > dist->initialized = false; > > kfree(dist->spis); > dist->nr_spis = 0; > - > - mutex_unlock(&kvm->lock); > } > > void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu) > @@ -286,7 +282,8 @@ void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu) > INIT_LIST_HEAD(&vgic_cpu->ap_list_head); > } > > -void kvm_vgic_destroy(struct kvm *kvm) > +/* To be called with kvm->lock held */ > +static void __kvm_vgic_destroy(struct kvm *kvm) > { > struct kvm_vcpu *vcpu; > int i; > @@ -297,6 +294,13 @@ void kvm_vgic_destroy(struct kvm *kvm) > kvm_vgic_vcpu_destroy(vcpu); > } > > +void kvm_vgic_destroy(struct kvm *kvm) > +{ > + mutex_lock(&kvm->lock); > + __kvm_vgic_destroy(kvm); > + mutex_unlock(&kvm->lock); > +} > + > /** > * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest > * is a GICv2. A GICv3 must be explicitly initialized by the guest using the > @@ -348,6 +352,10 @@ int kvm_vgic_map_resources(struct kvm *kvm) > ret = vgic_v2_map_resources(kvm); > else > ret = vgic_v3_map_resources(kvm); > + > + if (ret) > + __kvm_vgic_destroy(kvm); > + > out: > mutex_unlock(&kvm->lock); > return ret; > diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c > index 9bab867..834137e 100644 > --- a/virt/kvm/arm/vgic/vgic-v2.c > +++ b/virt/kvm/arm/vgic/vgic-v2.c > @@ -293,8 +293,6 @@ int vgic_v2_map_resources(struct kvm *kvm) > dist->ready = true; > > out: > - if (ret) > - kvm_vgic_destroy(kvm); > return ret; > } > > diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c > index 7df1b90..a4c7fff 100644 > --- a/virt/kvm/arm/vgic/vgic-v3.c > +++ b/virt/kvm/arm/vgic/vgic-v3.c > @@ -308,8 +308,6 @@ int vgic_v3_map_resources(struct kvm *kvm) > dist->ready = true; > > out: > - if (ret) > - kvm_vgic_destroy(kvm); > return ret; > } > > -- > 2.1.4 >
Hi Marc, On 12/01/2017 17:16, Marc Zyngier wrote: > Dmitry Vyukov reported that the syzkaller fuzzer triggered a > deadlock in the vgic setup code when an error was detected, as > the cleanup code tries to take a lock that is already held by > the setup code. > > The fix is to avoid retaking the lock when cleaning up, by > telling the cleanup function that we already hold it. > > Cc: stable@vger.kernel.org > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Thanks Eric > --- > virt/kvm/arm/vgic/vgic-init.c | 18 +++++++++++++----- > virt/kvm/arm/vgic/vgic-v2.c | 2 -- > virt/kvm/arm/vgic/vgic-v3.c | 2 -- > 3 files changed, 13 insertions(+), 9 deletions(-) > > diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c > index 5114391..c737ea0 100644 > --- a/virt/kvm/arm/vgic/vgic-init.c > +++ b/virt/kvm/arm/vgic/vgic-init.c > @@ -268,15 +268,11 @@ static void kvm_vgic_dist_destroy(struct kvm *kvm) > { > struct vgic_dist *dist = &kvm->arch.vgic; > > - mutex_lock(&kvm->lock); > - > dist->ready = false; > dist->initialized = false; > > kfree(dist->spis); > dist->nr_spis = 0; > - > - mutex_unlock(&kvm->lock); > } > > void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu) > @@ -286,7 +282,8 @@ void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu) > INIT_LIST_HEAD(&vgic_cpu->ap_list_head); > } > > -void kvm_vgic_destroy(struct kvm *kvm) > +/* To be called with kvm->lock held */ > +static void __kvm_vgic_destroy(struct kvm *kvm) > { > struct kvm_vcpu *vcpu; > int i; > @@ -297,6 +294,13 @@ void kvm_vgic_destroy(struct kvm *kvm) > kvm_vgic_vcpu_destroy(vcpu); > } > > +void kvm_vgic_destroy(struct kvm *kvm) > +{ > + mutex_lock(&kvm->lock); > + __kvm_vgic_destroy(kvm); > + mutex_unlock(&kvm->lock); > +} > + > /** > * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest > * is a GICv2. A GICv3 must be explicitly initialized by the guest using the > @@ -348,6 +352,10 @@ int kvm_vgic_map_resources(struct kvm *kvm) > ret = vgic_v2_map_resources(kvm); > else > ret = vgic_v3_map_resources(kvm); > + > + if (ret) > + __kvm_vgic_destroy(kvm); > + > out: > mutex_unlock(&kvm->lock); > return ret; > diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c > index 9bab867..834137e 100644 > --- a/virt/kvm/arm/vgic/vgic-v2.c > +++ b/virt/kvm/arm/vgic/vgic-v2.c > @@ -293,8 +293,6 @@ int vgic_v2_map_resources(struct kvm *kvm) > dist->ready = true; > > out: > - if (ret) > - kvm_vgic_destroy(kvm); > return ret; > } > > diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c > index 7df1b90..a4c7fff 100644 > --- a/virt/kvm/arm/vgic/vgic-v3.c > +++ b/virt/kvm/arm/vgic/vgic-v3.c > @@ -308,8 +308,6 @@ int vgic_v3_map_resources(struct kvm *kvm) > dist->ready = true; > > out: > - if (ret) > - kvm_vgic_destroy(kvm); > return ret; > } > >
diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c index 5114391..c737ea0 100644 --- a/virt/kvm/arm/vgic/vgic-init.c +++ b/virt/kvm/arm/vgic/vgic-init.c @@ -268,15 +268,11 @@ static void kvm_vgic_dist_destroy(struct kvm *kvm) { struct vgic_dist *dist = &kvm->arch.vgic; - mutex_lock(&kvm->lock); - dist->ready = false; dist->initialized = false; kfree(dist->spis); dist->nr_spis = 0; - - mutex_unlock(&kvm->lock); } void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu) @@ -286,7 +282,8 @@ void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu) INIT_LIST_HEAD(&vgic_cpu->ap_list_head); } -void kvm_vgic_destroy(struct kvm *kvm) +/* To be called with kvm->lock held */ +static void __kvm_vgic_destroy(struct kvm *kvm) { struct kvm_vcpu *vcpu; int i; @@ -297,6 +294,13 @@ void kvm_vgic_destroy(struct kvm *kvm) kvm_vgic_vcpu_destroy(vcpu); } +void kvm_vgic_destroy(struct kvm *kvm) +{ + mutex_lock(&kvm->lock); + __kvm_vgic_destroy(kvm); + mutex_unlock(&kvm->lock); +} + /** * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest * is a GICv2. A GICv3 must be explicitly initialized by the guest using the @@ -348,6 +352,10 @@ int kvm_vgic_map_resources(struct kvm *kvm) ret = vgic_v2_map_resources(kvm); else ret = vgic_v3_map_resources(kvm); + + if (ret) + __kvm_vgic_destroy(kvm); + out: mutex_unlock(&kvm->lock); return ret; diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c index 9bab867..834137e 100644 --- a/virt/kvm/arm/vgic/vgic-v2.c +++ b/virt/kvm/arm/vgic/vgic-v2.c @@ -293,8 +293,6 @@ int vgic_v2_map_resources(struct kvm *kvm) dist->ready = true; out: - if (ret) - kvm_vgic_destroy(kvm); return ret; } diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c index 7df1b90..a4c7fff 100644 --- a/virt/kvm/arm/vgic/vgic-v3.c +++ b/virt/kvm/arm/vgic/vgic-v3.c @@ -308,8 +308,6 @@ int vgic_v3_map_resources(struct kvm *kvm) dist->ready = true; out: - if (ret) - kvm_vgic_destroy(kvm); return ret; }
Dmitry Vyukov reported that the syzkaller fuzzer triggered a deadlock in the vgic setup code when an error was detected, as the cleanup code tries to take a lock that is already held by the setup code. The fix is to avoid retaking the lock when cleaning up, by telling the cleanup function that we already hold it. Cc: stable@vger.kernel.org Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- virt/kvm/arm/vgic/vgic-init.c | 18 +++++++++++++----- virt/kvm/arm/vgic/vgic-v2.c | 2 -- virt/kvm/arm/vgic/vgic-v3.c | 2 -- 3 files changed, 13 insertions(+), 9 deletions(-)