Re: [RESEND][PATCH v2] cxl: Check if vphb exists before iterating over AFU devices

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Le 22/11/2017 à 13:17, Vaibhav Jain a écrit :
During an eeh a kernel-oops is reported if no vPHB to allocated to the

typo, "to allocated". Not important, but....

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@xxxxxxxxxxxxxxx
Signed-off-by: Vaibhav Jain <vaibhav@xxxxxxxxxxxxxxxxxx>
---
Changelog:

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..18773343ab3e 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;
+

.. that one is more annoying.
afu->phb == NULL?

  Fred

  		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)





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