From: Hyunwoo Kim Date: Thu, 4 Jun 2026 20:59:15 +0000 (+0900) Subject: KVM: arm64: vgic: Check the interrupt is still ours before migrating it X-Git-Tag: v7.2-rc4~28^2~5^2~19 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0074b82cdfcb5fd13710a0ac308ade68ac6f6fbe;p=thirdparty%2Fkernel%2Flinux.git KVM: arm64: vgic: Check the interrupt is still ours before migrating it vgic_prune_ap_list() drops both ap_list_lock and irq_lock while migrating an interrupt to another vCPU. After reacquiring the locks it only checks that the affinity is unchanged (target_vcpu == vgic_target_oracle(irq)) before moving the interrupt, which assumes that an interrupt whose affinity is preserved is still queued on this vCPU's ap_list. That assumption no longer holds if the interrupt is taken off the ap_list while the locks are dropped. vgic_flush_pending_lpis() removes the interrupt from the list and sets irq->vcpu to NULL, but leaves enabled/pending/target_vcpu untouched. As the interrupt is still enabled and pending, vgic_target_oracle() returns the same target_vcpu, so the affinity check passes and list_del() is run a second time on an entry that has already been removed. Also check that the interrupt is still assigned to this vCPU (irq->vcpu == vcpu) before moving it. Fixes: 0919e84c0fc1 ("KVM: arm/arm64: vgic-new: Add IRQ sync/flush framework") Signed-off-by: Hyunwoo Kim Link: https://patch.msgid.link/aiHnI1mu6SGQrgnz@v4bel Signed-off-by: Marc Zyngier Cc: stable@vger.kernel.org --- diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c index 70a161383e5a..ccb7e3a90cd0 100644 --- a/arch/arm64/kvm/vgic/vgic.c +++ b/arch/arm64/kvm/vgic/vgic.c @@ -820,15 +820,16 @@ retry: raw_spin_lock(&irq->irq_lock); /* - * If the affinity has been preserved, move the - * interrupt around. Otherwise, it means things have - * changed while the interrupt was unlocked, and we - * need to replay this. + * If the interrupt is still ours and its affinity has + * been preserved, move it around. Otherwise, it means + * things have changed while the interrupt was unlocked + * (it may even have been taken off the list with its + * affinity left untouched), and we need to replay this. * * In all cases, we cannot trust the list not to have * changed, so we restart from the beginning. */ - if (target_vcpu == vgic_target_oracle(irq)) { + if (irq->vcpu == vcpu && target_vcpu == vgic_target_oracle(irq)) { struct vgic_cpu *new_cpu = &target_vcpu->arch.vgic_cpu; list_del(&irq->ap_list);