check vsc null pointer

[qiuming-best]

Signed-off-by: 李龙峰 lilongfeng@inspur.com

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Does your change fix a particular issue?

Fixes #(issue)
#5266
Fix a little problem, add a null pointer to judge.

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• Accepted the DCO. Commits without the DCO will delay acceptance.
• Created a changelog file or added /kind changelog-not-required as a comment on this pull request.
• Updated the corresponding documentation in site/content/docs/main.

[codecov-commenter]

Codecov Report

Merging #5303 (5d84a27) into release-1.9 (727c633) will decrease coverage by 0.00%.
The diff coverage is 0.00%.

@@               Coverage Diff               @@
##           release-1.9    #5303      +/-   ##
===============================================
- Coverage        41.37%   41.36%   -0.01%     
===============================================
  Files              211      211              
  Lines            18445    18449       +4     
===============================================
  Hits              7632     7632              
- Misses           10241    10245       +4     
  Partials           572      572              

Impacted Files	Coverage Δ
pkg/controller/backup_controller.go	48.46% <0.00%> (-0.29%)	⬇️

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