From 6344beb64054d8b9204b4167a0ae1f85439548a7 Mon Sep 17 00:00:00 2001 From: Jiang Yi Date: Wed, 27 Nov 2019 17:49:10 +0100 Subject: [PATCH] vfio/pci: call irq_bypass_unregister_producer() before freeing irq commit d567fb8819162099035e546b11a736e29c2af0ea upstream. Since irq_bypass_register_producer() is called after request_irq(), we should do tear-down in reverse order: irq_bypass_unregister_producer() then free_irq(). Specifically free_irq() may release resources required by the irqbypass del_producer() callback. Notably an example provided by Marc Zyngier on arm64 with GICv4 that he indicates has the potential to wedge the hardware: free_irq(irq) __free_irq(irq) irq_domain_deactivate_irq(irq) its_irq_domain_deactivate() [unmap the VLPI from the ITS] kvm_arch_irq_bypass_del_producer(cons, prod) kvm_vgic_v4_unset_forwarding(kvm, irq, ...) its_unmap_vlpi(irq) [Unmap the VLPI from the ITS (again), remap the original LPI] Signed-off-by: Jiang Yi Cc: stable@vger.kernel.org # v4.4+ Fixes: 6d7425f109d26 ("vfio: Register/unregister irq_bypass_producer") Link: https://lore.kernel.org/kvm/20191127164910.15888-1-giangyi@amazon.com Reviewed-by: Marc Zyngier Reviewed-by: Eric Auger [aw: commit log] Signed-off-by: Alex Williamson Signed-off-by: Greg Kroah-Hartman --- drivers/vfio/pci/vfio_pci_intrs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c index 3fa3f728fb39..2056f3f85f59 100644 --- a/drivers/vfio/pci/vfio_pci_intrs.c +++ b/drivers/vfio/pci/vfio_pci_intrs.c @@ -294,8 +294,8 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_device *vdev, irq = pci_irq_vector(pdev, vector); if (vdev->ctx[vector].trigger) { - free_irq(irq, vdev->ctx[vector].trigger); irq_bypass_unregister_producer(&vdev->ctx[vector].producer); + free_irq(irq, vdev->ctx[vector].trigger); kfree(vdev->ctx[vector].name); eventfd_ctx_put(vdev->ctx[vector].trigger); vdev->ctx[vector].trigger = NULL;