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wire 2026-05-21
stories 63
GitHub RSS Archive Reviews

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$ the-wire · showcase

RUNTIME MUTEX PROFILING LANDS, ARCHIVE/ZIP GETS CRITICAL FIX

By RepoJournal · Filed · About Go · Composed from the cited sources · methodology

Go's runtime now splits mutex lock tracking from preemption disable, unblocking safe contention profiling while a major Zip64 writer bug gets patched.

The core runtime change [1] separates gp.m.locks into two distinct mechanisms: one for tracking actual mutex holds and another for preemption disabling. This architectural split enables the mutex contention profiler to safely acquire mutexes during sampling without false positives. It's a careful fix that impacts how every Go program running on multiple goroutines manages synchronization visibility. Separately, archive/zip [2] shipped a critical writer-side Zip64 edge case fix that was causing mysterious failures when uploading files to external services. The bug manifested only in files larger than 4GiB but smaller than 6.5GiB, making it nearly impossible to debug. On the profile front, internal/profile [3] now correctly returns errors from gzip.Writer.Close in Profile.Write, preventing silent data corruption when pprof serialization fails due to disk full or broken pipes. The tooling desk is busy too: gopls [4] fixed generic method hover support and [5] corrected long-broken inlay hint logic in var specs, while the modernize analyzer [6] now handles negated error type assertions properly.

Action items

References

  1. [1] runtime: split gp.m.locks bits for lock vs acquirem golang/go ↗
  2. [2] archive/zip: fix writer-side Zip64 edge cases golang/go ↗
  3. [3] internal/profile: return error from gzip.Writer.Close in Profile.Write golang/go ↗
  4. [4] gopls/internal/golang: Hover: add test of generic methods ↗ golang/tools
  5. [5] gopls/internal/golang: InlayHint: fix bug in 'var' specs ↗ golang/tools
  6. [6] go/analysis/passes/modernize: errorsastype: support negated case ↗ golang/tools
  7. [7] x86/x86asm: support AVX instructions ↗ golang/arch

$ ls golang/reviews/ # the step-back reads

the week in review FIPS 140 crypto fixes land across SHA-3, TLS 1.2, HKDF the month in review Go toolchain patches three CVEs as gopls hits v0.24.0
Full archive → Weekly reviews →

Quick answers

What shipped in Go on May 21, 2026?
Go's runtime now splits mutex lock tracking from preemption disable, unblocking safe contention profiling while a major Zip64 writer bug gets patched. In total, 63 commits landed.
What were the notable Go updates?
runtime: split gp.m.locks bits for lock vs acquirem, archive/zip: fix writer-side Zip64 edge cases, and internal/profile: return error from gzip.Writer.Close in Profile.Write.
♥

$ log @golang --recent

RISC-V Zfa assembly support, and a faster archsimd unifier 9 shipped Plan 9 Mkdir race fixed, riscv64 gets clobberdead mode 7 shipped gopls closes a CVE on dash-prefixed module paths, and the exp collections get a Set 52 shipped Compiler stops lifting unsafe.Pointer arithmetic 35 shipped

$ log --all # elsewhere on the wire

Agent Security Quiet day in agent security as guard coverage reaches four clients Alignment & Post-training verl defaults Ascend RL mode, open-instruct unblocks SFT packing

$ ls showcases/

Safety Evals AI Red Teaming Agent Security Interpretability Alignment & Post-training

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