From 295f3bed20bc8f7c53a2adeef767fe901afe4dd3 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Thu, 23 Apr 2026 23:03:26 +0100 Subject: [PATCH] [virtio] Ensure that device is closed before unmapping regions Commit 988243c ("[virtio] Add virtio-net 1.0 support") erroneously placed the code to unmap the device regions before the code to unregister the network device. In the common case that the network device is still open at the time that we shut down to boot the OS, this results in the regions being accessed after having been unmapped. For 32-bit BIOS or for UEFI with no IOMMU enabled, the iounmap() operation is a no-op and so the driver still happens to work despite the ordering bug. For 64-bit BIOS or for UEFI with an IOMMU enabled, the iounmap() operation is not a no-op, and the driver will trigger a page fault. Fix by moving the call to unregister_netdev() to before the code that unmaps the device regions. Signed-off-by: Michael Brown --- src/drivers/net/virtio-net.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/drivers/net/virtio-net.c b/src/drivers/net/virtio-net.c index e47002798..32dad9ac0 100644 --- a/src/drivers/net/virtio-net.c +++ b/src/drivers/net/virtio-net.c @@ -684,11 +684,12 @@ static void virtnet_remove ( struct pci_device *pci ) { struct net_device *netdev = pci_get_drvdata ( pci ); struct virtnet_nic *virtnet = netdev->priv; + unregister_netdev ( netdev ); + virtio_pci_unmap_capability ( &virtnet->vdev.device ); virtio_pci_unmap_capability ( &virtnet->vdev.isr ); virtio_pci_unmap_capability ( &virtnet->vdev.common ); - unregister_netdev ( netdev ); netdev_nullify ( netdev ); netdev_put ( netdev ); }