Patch "IB/core: Fix sysfs registration error flow" has been added to the 4.9-stable tree

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

IB/core: Fix sysfs registration error flow

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
ib-core-fix-sysfs-registration-error-flow.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jack Morgenstein <[email protected]>
Date: Sun, 19 Mar 2017 10:55:57 +0200
Subject: IB/core: Fix sysfs registration error flow

From: Jack Morgenstein <[email protected]>

commit b312be3d87e4c80872cbea869e569175c5eb0f9a upstream.

The kernel commit cited below restructured ib device management so that the device kobject is initialized in ib_alloc_device.

As part of the restructuring, the kobject is now initialized in procedure ib_alloc_device, and is later added to the device hierarchy in the ib_register_device call stack, in procedure ib_device_register_sysfs (which calls device_add).

However, in the ib_device_register_sysfs error flow, if an error occurs following the call to device_add, the cleanup procedure device_unregister is called. This call results in the device object being deleted -- which results in various use-after-free crashes.

The correct cleanup call is device_del -- which undoes device_add without deleting the device object.

The device object will then (correctly) be deleted in the ib_register_device caller's error cleanup flow, when the caller invokes ib_dealloc_device.

---
 drivers/infiniband/core/sysfs.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -1301,7 +1301,7 @@ err_put:
 	free_port_list_attributes(device);
 
 err_unregister:
-	device_unregister(class_dev);
+	device_del(class_dev);
 
 err:
 	return ret;

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/ib-core-fix-sysfs-registration-error-flow.patch queue-4.9/ib-mlx4-fix-ib-device-initialization-error-flow.patch queue-4.9/ib-mlx4-reduce-sriov-multicast-cleanup-warning-message-to-debug-level.patch