title: 2241 illegal hardware instruction rails s
body: <p>Here's the problem: Unable to start an existing Rails project after upgrading to MacOS 10.15.1. The terminal shows this (below) after Rails s and going to localhost:3000.
  <code>SEGV received in SEGV handler [1]</code> 
  <code>1438 illegal hardware instruction rails s</code></p>
  
  <p>Note: The latest version of Xcode / command line is installed.</p>
  
  <p>After upgrading the OS successfully (MacOS 10.15.1), I followed the MacPorts migration guide successfully. Further, I successfully reinstalled RVM with Ruby 2.6.1, 2.6.3 and 2.6.5.</p>
  
  <p>Next, installed gem Rails -v 5.2.3 without issue. Tested this out with <code>Rails new TestProj</code>, it created a new project successfully, bundled and started the server with Rails s. No issues and saw the "Yay you're on Rails" page. So far so good.</p>
  
  <p>Then I CD into an existing Rails project, which was built on MacOS 10.14.x (Mojave) did a bundle update without any issues. Followed by a <code>rails s</code>, Puma started without issue. Here's where it gets <strong>strange</strong>, literally the second I goto the URL "localhost:3000" I immediately get this error.</p>
  
  <p><code>SEGV received in SEGV handler [1]</code> &lt;- this repeated
  <code>1438 illegal hardware instruction rails s</code></p>
  
  <p>I thought it might be a gem issue, tried installing the same gem set into the TestProj and everything work perfectly with a Puma starting and loading "Yay...". Finally, I've tried cloning the repo, bundling and I get the same error message. I'm pasting what I believe is the most important part of the log file into this post. I wonder if there is something in the Rails app that specifies certain hardware that needs updating? My apologies for its length, Hopefully, someone can interpret this better than I can and help troubleshoot. I'm happy to provide more information. Just not sure what else besides the log file you might need. Let me know. Thanks!</p>
  
  <pre><code>Exception Codes:       KERN_INVALID_ADDRESS at 0x00000000000000f8
  Exception Note:        EXC_CORPSE_NOTIFY
  
  Termination Signal:    Illegal instruction: 4
  Termination Reason:    Namespace SIGNAL, Code 0x4
  Terminating Process:   ruby [1438]
  
  VM Regions Near 0xf8:
  --&gt; 
      __TEXT                 0000000103679000-000000010367a000 [    4K] r-x/r-x SM=COW  /Users/USER/*
  
  Application Specific Information:
  abort() called
  
  Thread 11 Crashed:: thread_pool.rb*
  0   libsystem_pthread.dylib         0x00007fff681ac65f pthread_kill + 276
  1   libsystem_c.dylib               0x00007fff68077a1c abort + 120
  2   libruby.2.6.dylib               0x00000001038261d9 ruby_abort + 9
  3   libruby.2.6.dylib               0x0000000103826160 check_reserved_signal_ + 160 (signal.c:854)
  4   libruby.2.6.dylib               0x0000000103825fa4 sigsegv + 36 (signal.c:997)
  5   libsystem_platform.dylib        0x00007fff681a1b1d _sigtramp + 29
  6   ???                             000000000000000000 0 + 0
  7   libsystem_c.dylib               0x00007fff68077a1c abort + 120
  </code></pre>
  
  <p>I expect to cd into the existing RoR application and run <code>rails s</code> to start the server. Then go to <a href="http://localhost:3000" rel="nofollow noreferrer">http://localhost:3000</a> and see the application without crashing. The actual results are the following:
  ...</p>
  
  <pre><code>SEGV received in SEGV handler
  SEGV received in SEGV handler
  SEGV received in SEGV handler
  SEGV received in SEGV handler
  SEGV received in SEGV handler
  SEGV received in SEGV handler
  SEGV received in SEGV handler
  SEGV received in SEGV handler
  [1]    16523 illegal hardware instruction  rails s
  </code></pre>