On 23/11/17 14:38, Vaibhav Jain wrote:

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: 9e8df8a2196("cxl: EEH support") Cc: stable@vger.kernel.org Signed-off-by: Vaibhav Jain vaibhav@linux.vnet.ibm.com

Thanks for fixing it!

Acked-by: Andrew Donnellan andrew.donnellan@au1.ibm.com

---

Changelog:

v3 -> Fixed a reverse NULL check [Fred]

Resend -> Added the 'Fixes' info and marking the patch to stable tree [Mpe]

v2 -> Added the vphb NULL check to cxl_vphb_error_detected() [Andrew]

drivers/misc/cxl/pci.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c index bb7fd3f4edab..19969ee86d6f 100644 --- a/drivers/misc/cxl/pci.c +++ b/drivers/misc/cxl/pci.c @@ -2083,6 +2083,9 @@ 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;

@@ -2124,8 +2127,7 @@ static pci_ers_result_t cxl_pci_error_detected(struct pci_dev *pdev, * Tell the AFU drivers; but we don't care what they * say, we're going away. */

• 	if (afu->phb != NULL)
  

• 		cxl_vphb_error_detected(afu, state);
  

• 	cxl_vphb_error_detected(afu, state);
  

  } return PCI_ERS_RESULT_DISCONNECT; }

@@ -2265,6 +2267,9 @@ 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

@@ -2327,6 +2332,9 @@ 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)