livepatch/core: Check klp_func before 'klp_init_object_loaded'

hulk inclusion
category: feature
bugzilla: 186346, https://gitee.com/openeuler/kernel/issues/I4WBFN


CVE: NA

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Refer to following procedure:
  klp_init_object
    klp_init_object_loaded
      klp_find_object_symbol <-- 1. oops happened when old_name is NULL!!!
    klp_init_func  <-- 2. currently old_name is first time check here

This problem was introduced in commit 453d3845 ("livepatch/arm64:
fix func size less than limit") which exchange order of 'klp_init_func'
and 'klp_init_object_loaded' then cause old_name being used before check.

We move these checks before 'klp_init_object_loaded' and add several
logs to tell why check failed.

Fixes: 453d3845 ("livepatch/arm64: fix func size less than limit")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Reviewed-by: Cheng Jian <cj.chengjian@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>