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

Sasha Levin
2019-11-22T05:56:37Z

From: Ross Lagerwall <ross.lagerwall@citrix.com>

[ 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@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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