patch "isa: Prevent NULL dereference in isa_bus driver callbacks" added to driver-core-linus

This is a note to let you know that I've just added the patch titled

isa: Prevent NULL dereference in isa_bus driver callbacks

to my driver-core git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git
in the driver-core-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From: William Breathitt Gray <[email protected]>
Date: Wed, 8 Nov 2017 10:23:11 -0500
Subject: isa: Prevent NULL dereference in isa_bus driver callbacks

The isa_driver structure for an isa_bus device is stored in the device platform_data member of the respective device structure. This platform_data member may be reset to NULL if isa_driver match callback for the device fails, indicating a device unsupported by the ISA driver.

This patch fixes a possible NULL pointer dereference if one of the isa_driver callbacks to attempted for an unsupported device. This error should not occur in practice since ISA devices are typically manually configured and loaded by the users, but we may as well prevent this error from popping up for the 0day testers.

---
 drivers/base/isa.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

index cd6ccdcf9df0..372d10af2600 100644
@@ -39,7 +39,7 @@ static int isa_bus_probe(struct device *dev)
 {
 	struct isa_driver *isa_driver = dev->platform_data;
 
-	if (isa_driver->probe)
+	if (isa_driver && isa_driver->probe)
 		return isa_driver->probe(dev, to_isa_dev(dev)->id);
 
 	return 0;

@@ -49,7 +49,7 @@ static int isa_bus_remove(struct device *dev)
 {
 	struct isa_driver *isa_driver = dev->platform_data;
 
-	if (isa_driver->remove)
+	if (isa_driver && isa_driver->remove)
 		return isa_driver->remove(dev, to_isa_dev(dev)->id);
 
 	return 0;

@@ -59,7 +59,7 @@ static void isa_bus_shutdown(struct device *dev)
 {
 	struct isa_driver *isa_driver = dev->platform_data;
 
-	if (isa_driver->shutdown)
+	if (isa_driver && isa_driver->shutdown)
 		isa_driver->shutdown(dev, to_isa_dev(dev)->id);
 }
 

@@ -67,7 +67,7 @@ static int isa_bus_suspend(struct device *dev, pm_message_t state)
 {
 	struct isa_driver *isa_driver = dev->platform_data;
 
-	if (isa_driver->suspend)
+	if (isa_driver && isa_driver->suspend)
 		return isa_driver->suspend(dev, to_isa_dev(dev)->id, state);
 
 	return 0;

@@ -77,7 +77,7 @@ static int isa_bus_resume(struct device *dev)
 {
 	struct isa_driver *isa_driver = dev->platform_data;
 
-	if (isa_driver->resume)
+	if (isa_driver && isa_driver->resume)
 		return isa_driver->resume(dev, to_isa_dev(dev)->id);
 
 	return 0;

2.15.0