6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shuangpeng Bai commit 1af874e9f4ce22ccf8b10ab5462f32c70d3be21a upstream. register_pkey_tree() ignores errors from register_one_pkey_tree() and continues registering the remaining slaves. The per-slave error path has already released the pkey parent kobjects, but their pointers remain stored in the device. A later device cleanup therefore passes the stale pointers to kobject_put(), causing a use-after-free. Clear the parent pointers after releasing a failed slave tree and skip unregistered trees during device cleanup. This preserves the existing best-effort registration behavior while preventing a second cleanup of the failed tree. Fixes: c1e7e466120b ("IB/mlx4: Add iov directory in sysfs under the ib device") Cc: stable@vger.kernel.org Signed-off-by: Shuangpeng Bai Link: https://patch.msgid.link/20260816044510.3848996-1-shuangpeng.kernel@gmail.com Signed-off-by: Leon Romanovsky Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/hw/mlx4/sysfs.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/infiniband/hw/mlx4/sysfs.c +++ b/drivers/infiniband/hw/mlx4/sysfs.c @@ -753,11 +753,13 @@ err_add: kobject_put(p); } kobject_put(dev->dev_ports_parent[slave]); + dev->dev_ports_parent[slave] = NULL; err_ports: kobject_put(dev->pkeys.device_parent[slave]); /* extra put for the device_parent create_and_add */ kobject_put(dev->pkeys.device_parent[slave]); + dev->pkeys.device_parent[slave] = NULL; fail_dev: kobject_put(dev->iov_parent); @@ -787,6 +789,8 @@ static void unregister_pkey_tree(struct return; for (slave = device->dev->persist->num_vfs; slave >= 0; --slave) { + if (!device->pkeys.device_parent[slave]) + continue; list_for_each_entry_safe(p, t, &device->pkeys.pkey_port_list[slave], entry) {