The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 16b8fe4caf499ae8e12d2ab1b1324497e36a7b83 Mon Sep 17 00:00:00 2001

From: Eric Auger eric.auger@redhat.com Date: Fri, 13 Nov 2020 18:52:02 +0100 Subject: [PATCH] vfio/pci: Move dummy_resources_list init in vfio_pci_probe()

In case an error occurs in vfio_pci_enable() before the call to vfio_pci_probe_mmaps(), vfio_pci_disable() will try to iterate on an uninitialized list and cause a kernel panic.

Lets move to the initialization to vfio_pci_probe() to fix the issue.

Signed-off-by: Eric Auger eric.auger@redhat.com Fixes: 05f0c03fbac1 ("vfio-pci: Allow to mmap sub-page MMIO BARs if the mmio page is exclusive") CC: Stable stable@vger.kernel.org # v4.7+ Signed-off-by: Alex Williamson alex.williamson@redhat.com

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index e6190173482c..47ebc5c49ca4 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -161,8 +161,6 @@ static void vfio_pci_probe_mmaps(struct vfio_pci_device *vdev) int i; struct vfio_pci_dummy_resource *dummy_res;

- INIT_LIST_HEAD(&vdev->dummy_resources_list); - for (i = 0; i < PCI_STD_NUM_BARS; i++) { int bar = i + PCI_STD_RESOURCES;

@@ -1966,6 +1964,7 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) mutex_init(&vdev->igate); spin_lock_init(&vdev->irqlock); mutex_init(&vdev->ioeventfds_lock); + INIT_LIST_HEAD(&vdev->dummy_resources_list); INIT_LIST_HEAD(&vdev->ioeventfds_list); mutex_init(&vdev->vma_lock); INIT_LIST_HEAD(&vdev->vma_list);