---
id: "bug-1281"
status: "fixed"
status_updated: "2026-09-24"
status_note: ""
component: "unknown"
severity: "crash"
timestamp: "2026-06-30T03:25:00Z"
last_seen: "2026-09-19T09:00:00Z"
occurrences: 3
files: ["src/controller (restart/recovery/election path — exact site unknown", "no backtrace)"]
tags: ["7.2", "iomgr", "gdb", "election", "crash", "5.4", "restart", "recovery", "heisenbug", "accept-hang", "restart-stability", "segfault", "chaotic-soak"]
related: ["bug-1272", "bug-1282", "bug-924"]
legacy: true
---

# bug-1281: Restart-stability bug: a restarted xce_controller becomes unable to participate at chaotic round…

## Description
Restart-stability bug: a restarted xce_controller becomes unable to participate at chaotic round 4. Release build SIGSEGVs ('Segmentation fault (core dumped) --myname ctrl-3'); under gdb the SAME corruption manifests as a WEDGED inbound-accept/iomgr path (last accept 03:42:03 while the election timer keeps firing) so two restarted survivors can't exchange PreVotes -> permanent round-N election stall.

## Environment
_Not recorded (migrated from buglog.json)._

## Reproduction
_Not recorded (migrated from buglog.json)._

## Root cause
ROOT-CAUSED via gdb SIGQUIT all-thread bt: an ABBA lock-order deadlock in src/lib async dispatch. io_worker (netio.c:672) holds ep->lock then blocks on q->lock (dataq_enq); vdispatcher dataq_deq (dataq.c:65) holds q->lock then blocks on ep->lock via the vtask_eligible->endpoint_is_task_blocked (netio.c:1001) match callback. io_worker dies -> node stops accepting/answering PreVotes -> round-4 stall. In release the same ep/q race corrupts -> SIGSEGV. See bug-1282 (the actual dispatch defect).

## Fix
The crash/hang IS bug-1282 (UPSTREAM raft-drive-async dispatch deadlock). raft-ha-core-safety 7.2 stays blocked until bug-1282 is fixed upstream, then re-run the gate. No raft-ha-core-safety code change.

## Verification
_Not recorded (migrated from buglog.json)._

## References
- Related: bug-1272, bug-1282, bug-924