When the InstalledCode.entryPoint field is cleared[1], the HotSpotInstalledCode.codeStart field should also be cleared. That is, when making an nmethod non-entrant, all Java side values pointing to code in the nmethod should be cleared. This avoids an inconsistent view of the code.

[1] https://github.com/openjdk/jdk/search?q=set_InstalledCode_entryPoint