[PATCH v3] cxl: Check if vphb exists before iterating over AFU devices

Subsystems: char and misc drivers, the rest

STALE3212d

4 messages, 4 authors, 2017-11-24 · open the first message on its own page

[PATCH v3] cxl: Check if vphb exists before iterating over AFU devices

From: Vaibhav Jain <hidden>
Date: 2017-11-23 03:44:31

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 <redacted>
---
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)

-- 
2.14.3

Re: [PATCH v3] cxl: Check if vphb exists before iterating over AFU devices

From: Andrew Donnellan <hidden>
Date: 2017-11-23 03:42:09

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 <redacted>

Thanks for fixing it!

Acked-by: Andrew Donnellan <redacted>

quoted hunk

---
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)

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan@au1.ibm.com  IBM Australia Limited

Re: [PATCH v3] cxl: Check if vphb exists before iterating over AFU devices

From: Frederic Barrat <hidden>
Date: 2017-11-23 10:58:28


Le 23/11/2017 à 04:38, Vaibhav Jain a écrit :

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 <redacted>
---

Thanks.

Acked-by: Frederic Barrat <redacted>

quoted hunk

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)

Re: [v3] cxl: Check if vphb exists before iterating over AFU devices

From: Michael Ellerman <hidden>
Date: 2017-11-24 09:46:42

On Thu, 2017-11-23 at 03:38:57 UTC, 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 <redacted>
Acked-by: Andrew Donnellan <redacted>
Acked-by: Frederic Barrat <redacted>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/12841f87b7a8ceb3d54f171660f72a

cheers

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