On Thu, 4 Feb 2021 14:27:53 GMT, Andrew Haley <a...@openjdk.org> wrote:
> > > You read my mind, Andrew. Unless, of course, it's optimized to leverage > > > the fact that it's thread-specific.. > > > > > > it's thread-specific > > https://developer.apple.com/documentation/apple_silicon/porting_just-in-time_compilers_to_apple_silicon > > > Because pthread_jit_write_protect_np changes only the current thread’s > > > permissions, avoid accessing the same memory region from multiple > > > threads. Giving multiple threads access to the same memory region opens > > > up a potential attack vector, in which one thread has write access and > > > another has executable access to the same region. > > Umm, so how does patching work? We don't even know if other threads are > executing the code we need to patch. I thought java can handle that scenario in usual (non W^X systems) just fine, so we just believe jvm did everything right and it's safe to rewrite some code at specific moment. ------------- PR: https://git.openjdk.java.net/jdk/pull/2200
