Merge nucleic/hazy-opal-yak-cjc0 into dev

2026-07-17 23:48:59 -07:00
parent 608e7d0450
commit 65623f1c34
5 changed files with 403 additions and 202 deletions
@@ -89,7 +89,17 @@ extension OSFile {
                    if errno != EAGAIN && errno != EIO {
                        throw POSIXError(.init(rawValue: errno)!)
                    }
-                    break
+                    // [Nucleic vendored patch] Destination full: RETURN, don't `break`. Breaking
+                    // sent the outer `while true` straight back here — with the source idle and the
+                    // destination still full, neither leg could progress and this spun the caller's
+                    // thread at 100% until the peer drained. The caller is an epoll handler on
+                    // vminitd's SINGLE ProcessSupervisor poller thread, so the spin froze every
+                    // exec's stdio and every control-plane relay in the container at once (the
+                    // all-sessions "produced no output within 60s" stall / dead control plane).
+                    // The un-flushed bytes stay in the transfer pipe (`from.offset > to.offset`
+                    // persists in the SpliceFiles); the destination fd is registered for EPOLLOUT,
+                    // whose edge re-enters transferData and resumes the flush.
+                    return (from.offset - fromOffset, to.offset - toOffset, .success)
                }
                to.offset += bytesWrote
                if bytesWrote == 0 {