[Xen-devel] [PATCH AUTOSEL 4.14 035/127] xen/pciback: Check dev_data before using it

[Sasha Levin <sashal@xxxxxxxxxx>]

From: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>

[ Upstream commit 1669907e3d1abfa3f7586e2d55dbbc117b5adba2 ]

If pcistub_init_device fails, the release function will be called with
dev_data set to NULL.  Check it before using it to avoid a NULL pointer
dereference.

Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/xen/xen-pciback/pci_stub.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/xen/xen-pciback/pci_stub.c 
b/drivers/xen/xen-pciback/pci_stub.c
index 9e480fdebe1f0..8c250f4a3a97a 100644
--- a/drivers/xen/xen-pciback/pci_stub.c
+++ b/drivers/xen/xen-pciback/pci_stub.c
@@ -106,7 +106,8 @@ static void pcistub_device_release(struct kref *kref)
         * is called from "unbind" which takes a device_lock mutex.
         */
        __pci_reset_function_locked(dev);
-       if (pci_load_and_free_saved_state(dev, &dev_data->pci_saved_state))
+       if (dev_data &&
+           pci_load_and_free_saved_state(dev, &dev_data->pci_saved_state))
                dev_info(&dev->dev, "Could not reload PCI state\n");
        else
                pci_restore_state(dev);
-- 
2.20.1


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