From: Jack Morgenstein <jackm@xxxxxxxxxxxxxxxxxx>
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.
Fixes: 55aeed06544f6 ("IB/core: Make ib_alloc_device init the kobject")
Cc: <stable@xxxxxxxxxxxxxxx> # v4.2+
Signed-off-by: Jack Morgenstein <jackm@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx>
---
drivers/infiniband/core/sysfs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/infiniband/core/sysfs.c b/drivers/infiniband/core/sysfs.c
index daadf3130c9f..48bb75503255 100644
--- a/drivers/infiniband/core/sysfs.c
+++ b/drivers/infiniband/core/sysfs.c
@@ -1301,7 +1301,7 @@ int ib_device_register_sysfs(struct ib_device *device,
free_port_list_attributes(device);
err_unregister:
- device_unregister(class_dev);
+ device_del(class_dev);
err:
return ret;
--
2.12.0
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