Re: [PATCH] virtio-pci: Remove affinity hint before freeing the interrupt
From: Michael S. Tsirkin
Date: Wed Mar 08 2017 - 08:29:25 EST
On Wed, Mar 08, 2017 at 08:09:27AM +0000, Marc Zyngier wrote:
> virtio-pci registers a per-vq affinity hint when using MSIX,
> but fails to remove it when freeing the interrupt, resulting
> in this type of splat:
>
> [ 31.111202] WARNING: CPU: 0 PID: 2823 at kernel/irq/manage.c:1503 __free_irq+0x2c4/0x2c8
> [ 31.114689] Modules linked in:
> [ 31.116101] CPU: 0 PID: 2823 Comm: kexec Not tainted 4.10.0+ #6941
> [ 31.118911] Hardware name: Generic DT based system
> [ 31.121319] [<c022fb78>] (unwind_backtrace) from [<c0229d8c>] (show_stack+0x18/0x1c)
> [ 31.125017] [<c0229d8c>] (show_stack) from [<c05192f4>] (dump_stack+0x84/0x98)
> [ 31.128427] [<c05192f4>] (dump_stack) from [<c023d940>] (__warn+0xf4/0x10c)
> [ 31.131910] [<c023d940>] (__warn) from [<c023da20>] (warn_slowpath_null+0x28/0x30)
> [ 31.135543] [<c023da20>] (warn_slowpath_null) from [<c0290238>] (__free_irq+0x2c4/0x2c8)
> [ 31.139355] [<c0290238>] (__free_irq) from [<c02902d0>] (free_irq+0x44/0x78)
> [ 31.142909] [<c02902d0>] (free_irq) from [<c059d3a8>] (vp_del_vqs+0x68/0x1c0)
> [ 31.146299] [<c059d3a8>] (vp_del_vqs) from [<c056ca4c>] (pci_device_shutdown+0x3c/0x78)
>
> The obvious fix is to drop the affinity hint before freeing the
> interrupt.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Is this introduced by the changes in latest rc?
> ---
> drivers/virtio/virtio_pci_common.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> index df548a6fb844..5a84f8207c02 100644
> --- a/drivers/virtio/virtio_pci_common.c
> +++ b/drivers/virtio/virtio_pci_common.c
> @@ -106,9 +106,12 @@ static void vp_remove_vqs(struct virtio_device *vdev)
> if (vp_dev->msix_vector_map) {
> int v = vp_dev->msix_vector_map[vq->index];
>
> - if (v != VIRTIO_MSI_NO_VECTOR)
> - free_irq(pci_irq_vector(vp_dev->pci_dev, v),
> - vq);
> + if (v != VIRTIO_MSI_NO_VECTOR) {
> + unsigned int irq;
> + irq = pci_irq_vector(vp_dev->pci_dev, v);
> + irq_set_affinity_hint(irq, NULL);
> + free_irq(irq, vq);
> + }
> }
> vp_dev->del_vq(vq);
> }
> --
> 2.11.0