My rvm version is 1.29.12 and macOS 11.2.3, here is the error messages.
Error running 'env GEM_HOME=/Users/yuanyuanliu/.rvm/gems/ruby-1.9.3-p551@global GEM_PATH= /Users/yuanyuanliu/.rvm/rubies/ruby-1.9.3-p551/bin/ruby -d /Users/yuanyuanliu/.rvm/src/rubygems-2.7.9/setup.rb --no-document',
please read /Users/yuanyuanliu/.rvm/log/1618286479_ruby-1.9.3-p551/rubygems.install.log
then cat rubygems.install.log
Exception `LoadError' at /Users/yuanyuanliu/.rvm/rubies/ruby-1.9.3-p551/lib/ruby/1.9.1/rubygems.rb:1264 - cannot load such file -- rubygems/defaults/operating_system
Exception `LoadError' at /Users/yuanyuanliu/.rvm/rubies/ruby-1.9.3-p551/lib/ruby/1.9.1/rubygems.rb:1273 - cannot load such file -- rubygems/defaults/ruby
/Users/yuanyuanliu/.rvm/src/rubygems-3.0.9/lib/rubygems/core_ext/kernel_require.rb:54:in `require': /Users/yuanyuanliu/.rvm/src/rubygems-3.0.9/lib/rubygems/core_ext/kernel_warn.rb:15: syntax error, unexpected tLABEL (SyntaxError)
module_function define_method(:warn) {|*messages, uplevel: nil|
^
/Users/yuanyuanliu/.rvm/src/rubygems-3.0.9/lib/rubygems/core_ext/kernel_warn.rb:18: void value expression
/Users/yuanyuanliu/.rvm/src/rubygems-3.0.9/lib/rubygems/core_ext/kernel_warn.rb:43: syntax error, unexpected '}', expecting keyword_end
from /Users/yuanyuanliu/.rvm/src/rubygems-3.0.9/lib/rubygems/core_ext/kernel_require.rb:54:in `require'
from /Users/yuanyuanliu/.rvm/src/rubygems-3.0.9/lib/rubygems.rb:1390:in `<top (required)>'
from setup.rb:28:in `require'
from setup.rb:28:in `<main>'
'command gem pristine --version ' failed, you need to fix these gems manually.
Error running '__rvm_with ruby-1.9.3-p551 gemset_pristine',
please read /Users/yuanyuanliu/.rvm/log/1618301825_ruby-1.9.3-p551/gemset.pristine-ruby-1.9.3-p551.log
Making gemset ruby-1.9.3-p551@global pristine - please wait
'command gem pristine --version ' failed, you need to fix these gems manually.
Error running '__rvm_with ruby-1.9.3-p551@global gemset_pristine',
please read /Users/yuanyuanliu/.rvm/log/1618301825_ruby-1.9.3-p551/gemset.pristine-ruby-1.9.3-p551@global.log
Thanks in advance.