[ruby-core:106016] [Ruby master Bug#18286] Universal arm64/x86_84 binary built on an x86_64 machine segfaults/is killed on arm64

Issue #18286 has been updated by ccaviness (Clay Caviness).


Lack of codesigning on Apple Silicon is an excellent guess, but unfortunately does not seem to be the cause here as Tim's demonstrated above (and I've verified as well). I first noticed this issue when testing a `ruby` that was fully signed with a public developer cert.

----------------------------------------
Bug #18286: Universal arm64/x86_84 binary built on an x86_64 machine segfaults/is killed on arm64
https://bugs.ruby-lang.org/issues/18286#change-94569

* Author: ccaviness (Clay Caviness)
* Status: Open
* Priority: Normal
* ruby -v: 3.0.2
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
A universal arm64/x86_84 ruby binary for macOS built on a x86_64 machine segfaults/is killed when executed on an arm64 machine.

To reproduce:
* On an Intel Mac: `git clone https://github.com/ruby/ruby && cd ruby && git checkout v3_0_2 && ./autogen.sh && ./configure --with-arch=arm64,x86_64 && make -j$(sysctl -n hw.ncpu)`
* Copy the built `./ruby` binary to an Apple Silicon machine
* Attempt to execute it

Expected:
The universal `ruby` binary works correctly on both devices

Actual:
The universal `ruby` binary crashes with either `Segmentation fault: 11` or `Killed: 9` (this seems to occur if `arm64e` is used instead of `arm64`).

Details:
I'm attempting to build a universal Ruby for macOS that will run on both Intel (x86_64) and Apple Silicon (arm64) machines.

It seemed initially that this was as easy as adding `--with-arch=arm64,x86_64` to `./configure` would do it, as it produced a `ruby` binary that reports as `Mach-O universal binary with 2 architectures: [x86_64:Mach-O 64-bit executable x86_64] [arm64]`

This `ruby` works correctly on the Intel machine I built in on, but does not work when copied to an Apple Silicon device. The reverse, however, seems to work. That is, if I build the universal ruby on an Apple Silicon machine, the `ruby` binary that's built seems to work correctly on both Intel and Apple Silicon machines.

Intel:
```
$ ./ruby -v
ruby 3.0.2p107 (2021-07-07 revision 0db68f0233) [universal.x86_64-darwin21]
```

Apple Silicon:
```
$ ./ruby -v
Segmentation fault: 11
$ lldb ./ruby
(lldb) target create "./ruby"
Current executable set to '/Users/crc/ruby' (arm64).
(lldb) run
Process 77071 launched: '/Users/crc/ruby' (arm64)
Process 77071 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x8)
    frame #0: 0x00000001002176b8 ruby`ruby_vm_special_exception_copy + 16
ruby`ruby_vm_special_exception_copy:
->  0x1002176b8 <+16>: ldr    x0, [x0, #0x8]
    0x1002176bc <+20>: bl     0x10011fed8               ; rb_class_real
    0x1002176c0 <+24>: bl     0x10012070c               ; rb_obj_alloc
    0x1002176c4 <+28>: mov    x20, x0
Target 0: (ruby) stopped.
(lldb) ^D
```

I also attempted the same thing with ruby 2.7.4 source, with the same result.



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