| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 40/80] IB/core: Fix sysfs registration error flow | Date | Thu, 18 May 2017 12:48:22 +0200 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: Jack Morgenstein <jackm@dev.mellanox.co.il>
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.
Fixes: 55aeed06544f6 ("IB/core: Make ib_alloc_device init the kobject") Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il> Signed-off-by: Leon Romanovsky <leon@kernel.org> Signed-off-by: Doug Ledford <dledford@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/infiniband/core/sysfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/infiniband/core/sysfs.c +++ b/drivers/infiniband/core/sysfs.c @@ -1301,7 +1301,7 @@ err_put: free_port_list_attributes(device); err_unregister: - device_unregister(class_dev); + device_del(class_dev); err: return ret;
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