!6032 gtp: fix use-after-free and null-ptr-deref in gtp_genl_dump_pdp()

Merge Pull Request from: @ci-robot 
 
PR sync from: Zhengchao Shao <shaozhengchao@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/NLAYEFY3ZVPBICRO562SCGB7RZ2CXANI/ 
 
https://gitee.com/src-openeuler/kernel/issues/I9E2MH 
 
Link:https://gitee.com/openeuler/kernel/pulls/6032

 

Reviewed-by: Liu YongQiang <liuyongqiang13@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>