[PATCH] vfio/pci: Move dummy_resources_list init in vfio_pci_probe()

[PATCH] vfio/pci: Move dummy_resources_list init in vfio_pci_probe()

[Eric Auger]

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+
---
 drivers/vfio/pci/vfio_pci.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

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);
-- 
2.21.3

Re: [PATCH] vfio/pci: Move dummy_resources_list init in vfio_pci_probe()

[Alex Williamson]

On Fri, 13 Nov 2020 18:52:02 +0100
Eric Auger <eric.auger@redhat.com> wrote:

> 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+
> ---
>  drivers/vfio/pci/vfio_pci.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)

Thanks, Eric.  Applied to vfio next branch for v5.11.

Alex

> 
> 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);