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

Subsystems: char and misc drivers, the rest

STALE3236d

2 messages, 2 authors, 2017-11-22 · open the first message on its own page

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

From: Vaibhav Jain <hidden>
Date: 2017-11-22 08:09:55

During an eeh a kernel-oops is reported if no vPHB to 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.

Signed-off-by: Vaibhav Jain <redacted>

---
Changelog:
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;
+
 		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

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

From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2017-11-22 10:18:52

Vaibhav Jain [off-list ref] writes:
During an eeh a kernel-oops is reported if no vPHB to 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.

Signed-off-by: Vaibhav Jain <redacted>

---
Changelog:
v2 -> Added the vphb NULL check to cxl_vphb_error_detected() [Andrew]
Fixes: ?

Stable?

cheers
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