Fix/memoryleak

[siguangli]

Before submitting a new pull request, please make sure:

• Test cases have been added/updated/passed for the code you will submit.
• Documentation has added or updated.
• Commit message is following the Convention Commit guideline with maximum 72 characters.
• Squash the repeat code commits, short patches are welcome.

[hippy-service]

Hi, @siguangli. Thanks for your PR! 👏

🏷️ You can leave a comment in this PR with #help tag when you need help (e.g. some status checks run failed due to internal issue), admin team members will help asap.

[tencent-adm]

Thank you for your submission, we really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

✅ siguangli
❌ siguangli2018
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[iPel]

lgtm

[hippy-service]

🎉 It seems that this pull request has been approved by all required reviewers. But it has more than one normal commit, I will notify admin team member to merge it manually, please wait a moment.

• SHA: dee2a2b