ibcore: Fix sysfs registration error flow

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.

Linux commit:
b312be3d87e4c80872cbea869e569175c5eb0f9a

PR:		264472
MFC after:	3 days
Sponsored by:	NVIDIA Networking

1 files changed, 1 insertions, 1 deletions

diff --git a/sys/ofed/drivers/infiniband/core/ib_sysfs.c b/sys/ofed/drivers/infiniband/core/ib_sysfs.c
index 4cbb69ad899b..63f6c2641b83 100644
--- a/sys/ofed/drivers/infiniband/core/ib_sysfs.c
+++ b/sys/ofed/drivers/infiniband/core/ib_sysfs.c
@@ -1366,7 +1366,7 @@ err_put:
 	free_port_list_attributes(device);
 
 err_unregister:
-	device_unregister(class_dev);
+	device_del(class_dev);
 
 err:
 	return ret;