Host (dominant): AppStore.reconcileLocks polls every 3s on the MainActor
while any lock is held — effectively forever, since interrupted/errored
sessions deliberately retain locks. Each pass ran heldPathDisposition's
diverges() as three held×unmerged scans with two split-allocations per
pathsOverlap call, pinning the main thread for tens of seconds per pass
on a diverged trunk (hang-reports 2026-07-28: 100% of samples in
reconcileLocks→heldPathDisposition→pathsOverlap). That froze running
sessions' transcripts and starved the spawn path into the 60s
"produced no output" watchdog. pathsOverlap is now allocation-free
bytewise comparison with identical semantics, and divergentHeldPaths
answers all three questions from one O((held+unmerged)·depth) set.
Guest (persistence): VsockProxy threaded ONE offset pair through BOTH
relay directions; once the EAGAIN-return backpressure patch let pending
bytes persist, traffic in the other direction skewed the shared
counters, made the write leg unreachable, and spun the single
ProcessSupervisor poller thread forever — container-wide dead control
plane until VM recreation, triggered by exactly the backpressure the
host hang created. Each direction now owns its own pipe and counters
(OSFile.RelayDirection), and source EOF is only surfaced after the
pipe drains so SHUT_WR can't truncate a parked tail. Vendored patch
docs updated (#15); inert until the initfs image is rebuilt+repointed.
Co-Authored-By: Claude Fable 5 <[email protected]>
abkslmandClaude Fable 5
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