diff --git a/lib/process_shared/posix/libc.rb b/lib/process_shared/posix/libc.rb
index b579239..13a7345 100644
--- a/lib/process_shared/posix/libc.rb
+++ b/lib/process_shared/posix/libc.rb
@@ -26,7 +26,11 @@ module ProcessShared
         #
         # Fallback to attempting to load from same directory as this file.
         helper = 'process_shared/posix/helper.' + suffix
-        path = Gem::Specification.find_all.find{|g| g.name == 'process_shared'}.extensions_dir
+        gem_spec = Gem::Specification.find_all.find{|g| g.name == 'process_shared'}
+        path = gem_spec.extensions_dir
+        unless path.end_with?(gem_spec.full_name)
+          path = File.join(path, gem_spec.full_name)
+        end
 
         if  defined?(Truffle)
           ffi_lib(File.join(::Truffle::Boot.toolchain_paths(:LD_LIBRARY_PATH), 'libgraalvm-llvm.so.1'), File.join(path, helper))