---
id: "bug-1884"
status: "fixed"
status_updated: "2026-09-29"
status_note: ""
component: "scheduler"
severity: "leak"
timestamp: "2026-09-29T08:20:03Z"
last_seen: "2026-09-29T08:20:03Z"
occurrences: 1
files: ["src/scheduler/src/sim_loop.c", "src/scheduler/src/sim.c", "src/scheduler/src/plugins/limit.c", "src/scheduler/src/main.c"]
tags: ["scheduler", "sim", "asan", "lsan", "leak"]
related: ["bug-1632", "bug-1763"]
fix_commits: ["9b61fd99", "c89e4e45", "8134b75b", "ebfe4794", "c1cd8f91", "90b99d91"]
gitea_issue: 335
gitea_synced_status: "fixed"
gitea_synced_hash: "bfbff0444e9c"
---

# bug-1884: standalone ASAN xce_scheduler --sim exits 1: LeakSanitizer reports 17 MB still allocated at exit

## Description
**Observed:** an ASAN build of `xce_scheduler --sim=<file> --sim-verify`
replays the whole recording (0 MISMATCH lines) and then exits 1 because
LeakSanitizer reports at exit:
```
==2234882==ERROR: LeakSanitizer: detected memory leaks
...
SUMMARY: AddressSanitizer: 17041405 byte(s) leaked in 1187 allocation(s).
```
Of the 17,041,405 bytes, 17,036,261 are indirect and 5,144 direct.
Grouped by first scheduler/lib frame (bytes, leak groups):
- `kvtab_init` (lib/kv.c:106): 16,941,432 in 15 -- core kv tables, reachable only from leaked roots
- `sim_process_replay_event_message` (sim_loop.c:403): 49,688 in 54 -- decoded replay events (e.g. `decode_JobStateChangeEvent_ptr`)
- `xkvmgr_add` (lib/kvmgr.c:114): 21,376 in 9
- `sim_locate_and_load_snapshot` (sim.c:224): 14,347 in 106 -- snapshot decode (`decode_Conf4Sched` / `decode_QueueConf_list`)
- `put_resvals` (resource.c:99) via limit.c `update_limit_res_value` and `sched_update_res_accounts`: 2,048 in 2
- smaller: `parse_resreq`, `core_build_job`, `sched_ctx_init`, `match_job_host_limit_`

The indirect bulk fits the simulator never tearing down its core at exit
(its picker/allocator threads are never joined, see bug-1632/bug-1763);
the direct groups may include real per-event leaks.

**Expected:** a clean replay exits 0 under ASAN with LeakSanitizer enabled,
or the exit-time teardown frees what the driver owns.
**Impact:** leak; for scripts, any ASAN `--sim` replay must set
`ASAN_OPTIONS=detect_leaks=0` or its exit code is always 1, which masks real
failures and hides any genuine per-event leak among the exit-time noise.
Release builds are unaffected at exit; a per-event leak would still grow a
long replay's memory.
**Found by:** spec task (libxce-alloc-preason-equality 5.3, live
default-settings replay, 2026-09-29)

## Environment
- OS: no /etc/os-release; Docker container; NixOS kernel; kernel Linux 6.18.33 x86_64
- libc: glibc 2.42-47 (interpreter /nix/store/wb6rhpznjfczwlwx23zmdrrw74bayxw4-glibc-2.42-47/lib/ld-linux-x86-64.so.2)
- Toolchain: gcc (GCC) 15.2.0, meson 1.9.1
- Build: asan (src/xce.build.discrete, debug + b_sanitize=address)
- Code: scheduler-framework @ 4500ec46-dirty
- Deployment: n/a (standalone simulation mode, no cluster); the replay file was recorded by a local 3-node HA soak (run-ha-soak.sh, 2 sequential rounds, xcecd_virtual worker) at /home/claude/tmp/xce-alloceq-53

## Reproduction
1. `bash src/tools/xce-build.sh scheduler asan` (or any ASAN build dir)
2. `src/xce.build/scheduler/xce_scheduler --sim=/home/claude/tmp/bug-1884/scheduler-replay-20260929-064412.replay --sim-verify --logfile /tmp/sim.log; echo rc=$?`
3. Observe `rc=1` and the LeakSanitizer SUMMARY on stderr (before the fix). With `ASAN_OPTIONS=detect_leaks=0` the same run exits 0.
- Frequency: deterministic (2/2 runs, identical totals, 2026-09-29); also seen on every recording of /home/claude/tmp/xce-ha-dc-soak
- Evidence: /home/claude/tmp/bug-1884/lsan-report.txt (full report), /home/claude/tmp/bug-1884/scheduler-replay-20260929-064412.replay

## Root cause
Nothing tore the simulator down (threads never joined, core never
finalized), and teardown then exposed a chain of ownership gaps, several of
which also leak at runtime in normal mode:
- xce_sched_core_fini() never destroyed the plugin/job/worker/queue/user/
  project registries, the shared-value arrays, the config or the
  pend_updates queues; kill_sched_job/queue/worker are shallow by design
  (a failed key_add() runs them and callers keep using the value).
- sim_alloc.c's allocator stand-ins ran a full xce_sched_core_init(),
  re-initializing the process-wide string and selector tables.
- plugin_unregister() key_del()'d from the registry being destroyed; the
  limit plugin's usage-instance table used kill_limit on xce_vres_t;
  add_vres() put a bare calloc() into the resobj registry.
- Replay-event payloads were never released after the push ("accepted
  leak"); the start snapshot's non-config remainder was never freed.
- kill_sched_resval() never freed the value struct (free_Value() frees only
  a string's buffer) -- every replaced value leaked, WORKERS_PUSH updates
  included; put_resvals() created a second value for a repeated index.
- dup_val() tested which == XCE_VAL_STRING (0 = Value_u_ivalue32): real
  strings were shallow-copied, a nonzero int32 went to makeString().
- The satisfy checks re-initialized the ctx's live unmeet vector per
  candidate host; replaced pend reasons, old parsed resreqs (JOB_UPDATE,
  duplicate JOBS_PUSH), the parser's error message and each written
  snapshot were never freed; the simulator never freed decision structs.

## Fix
Six commits: 9b61fd99 (sim teardown, core registries, allocator stand-ins,
plugin_unregister, kill_vres), c89e4e45 (replay-event payload release),
8134b75b (core owns/frees its config; start snapshot freed), ebfe4794 (sim
decisions, fcfs plugin, pend_updates), c1cd8f91 (collect-then-free
teardown for job/worker/queue/resource tables with shallow killers kept;
dup_val; unmeet; add_vres via makeResource; plugin_register_core rejects
duplicates up front), 90b99d91 (kill_sched_resval frees the value;
put_resvals repeated index; resreq/schedobj/pend-reason/errmsg frees;
write_snapshot_entry frees its snapshot, save side strdup()s).
Exit-time leak on the reproduction replay: 17,041,405 bytes -> 0.
Not fixed here (separate): normal mode never frees decision structs;
queues rejected on config re-apply and a config replaced by CONFIG_PUSH
are not freed; select parse errors inside the resreq grammar are ignored.

## Verification
- Test: test_cli_batch_replay_exits_clean_under_leak_detection in src/scheduler/testsuite/test_sim_discrete_clock.c (real binary, two-session fixture, --sim-verify --sim-output, detect_leaks=1): RED before (exit 1), GREEN after (exit 0)
- Suites: ASAN debug build (src/xce.build.discrete), `meson test --no-suite xceadmin`: 117/117 OK, 0 sanitizer reports (2026-09-29)
- Live: 3-round sequential HA soak on rebuilt ASAN binaries (/home/claude/tmp/xce-bug1884-soak): PASS, zero job loss, SIMVERIFY 4 files 0 mismatches, no sanitizer report in the live scheduler's stderr; all 13 recordings (this soak + xce-alloceq-53 + xce-ha-dc-soak) replay with detect_leaks=1: exit 0, 0 mismatches, no leak report

## References
- Related: bug-1632, bug-1763 (sim picker/allocator threads never joined)
- run-ha-soak.sh replay gate already runs `--sim` with `ASAN_OPTIONS=detect_leaks=0`