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FAILED: patch "[PATCH] vfio/pci: Move dummy_resources_list init in vfio_pci_probe()" failed to apply to 4.9-stable tree

PATCH [email protected] 1 participant 1 message Dec 28, 2020

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The patch below does not apply to the 4.9-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 <[email protected]>.

thanks,

greg k-h

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

From 16b8fe4caf499ae8e12d2ab1b1324497e36a7b83 Mon Sep 17 00:00:00 2001
From: Eric Auger <[email protected]>
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.

Fixes 05f0c03fbac1 ("vfio-pci: Allow to mmap sub-page MMIO BARs if the mmio page is exclusive")
CC Stable <[email protected]> # v4.7+
drivers/vfio/pci/vfio_pci.c +1 -2
index e6190173482c..47ebc5c49ca4 100644
@@ -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);