macOS 14.4 causes JVM crashes

Original Article ↗ Hacker News Discussion ↗

Scope and Impact

  • macOS 14.4 on Apple silicon causes unexpected termination of JVM-based processes via SIGKILL instead of the previously handled signals (SIGSEGV/SIGBUS).
  • Affects Java 8 through early-access JDK 22 according to Oracle’s updated statement; earlier comments note evolving understanding (some initially thought 20/21 unaffected).
  • Reports of intermittent crashes in IntelliJ, Rider, RubyMine, Eclipse, MATLAB (via Corretto 8), and other JVM-based tools; frequency varies from “less than daily” to “hours of work before one crash.”
  • Many advise postponing upgrade to 14.4, especially for heavy Java/IDE users; those already on 14.3.x often choose to stay put.

Technical Behavior Change

  • macOS 14.4 changes how protected-memory violations are handled when a JIT-writing thread is involved: previously generated catchable signals, now often produce SIGKILL.
  • JVMs use deliberate protected-memory accesses for “zero-cost” checks (safepoints, GC, stack/heap growth, NPEs, mmap truncation handling).
  • Some note macOS documentation (e.g., mprotect) historically promised SIGSEGV/SIGBUS for protection violations, matching JVM assumptions.

POSIX / Standards Debate

  • One side: this breaks POSIX/UNIX expectations; segmentation violations should signal, not unconditionally kill, and changing this in a minor release is a kernel bug.
  • Other side: POSIX may not strictly forbid SIGKILL here, and the OS can terminate processes at will; compliance status is debated, with references to POSIX text but no consensus.

Security vs Compatibility

  • Security-focused view: killing a JIT thread that illegally writes to executable/protected memory is “doing the right thing” and reduces attack surface; using signals for this was always risky.
  • Compatibility-focused view: “don’t break userspace”; Java’s approach is standard systems practice across OSes, long-standing, and should not suddenly stop working.

Workarounds and Alternatives

  • Suggested temporary mitigations: run Java under Rosetta; avoid upgrading; use Linux (bare metal or VM) or Windows/WSL for development.
  • Questions raised about other JIT runtimes (e.g., JavaScript engines) and whether they’re similarly affected; unclear from thread.

Apple Process and Motivation

  • Many criticize Apple’s QA and release process: bug was absent in 14.4 betas but appeared in final, suggesting last-minute kernel changes.
  • Some speculate about stricter enforcement of JIT entitlements; others reject this and see it as a straightforward regression.
  • Later comments note Apple has shipped a follow-up fix, used as evidence that the breakage was indeed on Apple’s side.