FIX BUG(Issue #1776): Switching pthread causes coredump when bthread local variable is destructed

[zhaodongzhi]

FIX BUG(Issue #1776): Switching pthread causes coredump when bthread local variable is destructed

If the bthread local destructor specified by bthread_key_create calls bthread_mutex_lock
it may cause TaskGroup::task_runner->return_keytable to switch pthreads after execution
causing coredump

[wwbmmm]

Thanks for reporting the issue and submitting this PR!
I think it's better to add some comments to explain the code, or add some test cases, to prevent future modification from breaking this case.

[zhaodongzhi]

Thanks for reporting the issue and submitting this PR! I think it's better to add some comments to explain the code, or add some test cases, to prevent future modification from breaking this case.

OK! I will add some test cases and then update this pr

[wwbmmm]

Thanks for reporting the issue and submitting this PR! I think it's better to add some comments to explain the code, or add some test cases, to prevent future modification from breaking this case.

OK! I will add some test cases and then update this pr

@zhaodongzhi Any update of this PR?

[chenBright]

This bug has been fixed in #2558 .