commit 12841f87b7a8ceb3d54f171660f72a86941bfcb3 upstream, for 4.9.
During an eeh a kernel-oops is reported if no vPHB is allocated to the
AFU. This happens as during AFU init, an error in creation of vPHB is
a non-fatal error. Hence afu->phb should always be checked for NULL
before iterating over it for the virtual AFU pci devices.
This patch fixes the kenel-oops by adding a NULL pointer check for
afu->phb before it is dereferenced.
Fixes: 9e8df8a21963 ("cxl: EEH support")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Vaibhav Jain <vaibhav@xxxxxxxxxxxxxxxxxx>
Acked-by: Andrew Donnellan <andrew.donnellan@xxxxxxxxxxx>
Acked-by: Frederic Barrat <fbarrat@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
---
Changelog:
Rebased the upstream patch over stable 4.9 tree
---
drivers/misc/cxl/pci.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
index eef202d4399b..a5422f483ad5 100644
--- a/drivers/misc/cxl/pci.c
+++ b/drivers/misc/cxl/pci.c
@@ -1758,6 +1758,9 @@ static pci_ers_result_t cxl_vphb_error_detected(struct cxl_afu *afu,
/* There should only be one entry, but go through the list
* anyway
*/
+ if (afu->phb == NULL)
+ return result;
+
list_for_each_entry(afu_dev, &afu->phb->bus->devices, bus_list) {
if (!afu_dev->driver)
continue;
@@ -1801,6 +1804,11 @@ static pci_ers_result_t cxl_pci_error_detected(struct pci_dev *pdev,
/* Only participate in EEH if we are on a virtual PHB */
if (afu->phb == NULL)
return PCI_ERS_RESULT_NONE;
+
+ /*
+ * Tell the AFU drivers; but we don't care what they
+ * say, we're going away.
+ */
cxl_vphb_error_detected(afu, state);
}
return PCI_ERS_RESULT_DISCONNECT;
@@ -1941,6 +1949,9 @@ static pci_ers_result_t cxl_pci_slot_reset(struct pci_dev *pdev)
if (cxl_afu_select_best_mode(afu))
goto err;
+ if (afu->phb == NULL)
+ continue;
+
list_for_each_entry(afu_dev, &afu->phb->bus->devices, bus_list) {
/* Reset the device context.
* TODO: make this less disruptive
@@ -2003,6 +2014,9 @@ static void cxl_pci_resume(struct pci_dev *pdev)
for (i = 0; i < adapter->slices; i++) {
afu = adapter->afu[i];
+ if (afu->phb == NULL)
+ continue;
+
list_for_each_entry(afu_dev, &afu->phb->bus->devices, bus_list) {
if (afu_dev->driver && afu_dev->driver->err_handler &&
afu_dev->driver->err_handler->resume)
--
2.14.3