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Rongsong Shen 6e05dc1523 fix(libxce): endpoint reference count — kill teardown-vs-dispatch UAF (bug-1298, task 5.8)
The io_worker freed an endpoint (endpoint_killer, cluster.c) on connection
teardown while the vtask dispatcher concurrently read ep->busy
(endpoint_is_task_blocked, netio.c) on a queued vtask — a heap-use-after-free
that ABORTed a controller mid-chaotic-soak (round 4), dropping the cluster
below quorum so no primary could be elected.

Replace the accumulation of ad-hoc ep-lifetime patches (bug-1282 lockless busy,
bug-1197 dispatch_inflight drain + deferred teardown vtask) with one principled
invariant: an endpoint lives until its reference count reaches 0.

  - endpoint_t.refcnt (_Atomic) + heap_alloc flag; endpoint_get starts a heap ep
    at refcnt=1 (the owner ref).
  - endpoint_ref/endpoint_unref: the last unref fini's + frees a heap ep.
    Embedded eps (client ctx->ep, heap_alloc=0) are never freed here — their
    container owns them — so a vtask-balanced ref/unref pair is a safe no-op.
  - vtask_enq takes a per-vtask ref on the bound ep BEFORE publishing the task to
    the dispatcher; run_task / taskq_item_killer release it. So the dispatcher can
    read ep->busy on any queued vtask without the ep being freed underneath it.
  - every HEAP-ep teardown site (endpoint_killer, handle_endpoint_error, the
    vote/prevote connect-fail paths, the vote-ep loser/teardown paths, the standby
    reconnect/eviction paths) now drops its owner ref via endpoint_unref instead of
    raw endpoint_fini+free. Several of those also leaked the ep struct before
    (endpoint_fini-only); unref fixes the leak too.

Validation: controller_unit_test 182 tests / 0 failures (test_ha_vep_teardown
updated — its OFF-path test asserted the old struct leak, now fixed). 6-round
ASAN chaotic soak: ZERO AddressSanitizer reports, ctrl-3 no longer crashes at
round 4, all 6 rounds elect at bounded terms. (The pre-existing iomgr_fini ->
SSL_CTX_free abort under openssl 3.6 in the aggregate test binary is unrelated.)

Note: with the crash gone, the soak now reaches rounds 4-6 for the first time and
surfaces a SEPARATE, pre-existing committed-job-loss/divergence (the bug-795/828
failover catch-up gap; ha-commit-durability domain) — not a refcount regression
(ASAN clean; rounds 1-3 are loss-free).
2026-06-30 14:24:47 +00:00
.claude feat(xce-build): add non-ASAN debug + release profiles; root-cause bug-1286 with the debug build 2026-06-30 09:15:36 +00:00
.kiro docs(raft-ha-core-safety): 5.7 verified (election resonance fixed); round-4 re-roots to bug-1298 UAF (task 5.8) 2026-06-30 13:39:55 +00:00
.wolf docs(raft-ha-core-safety): 5.7 verified (election resonance fixed); round-4 re-roots to bug-1298 UAF (task 5.8) 2026-06-30 13:39:55 +00:00
docs/superpowers/plans claude skills 2026-05-29 15:00:06 +08:00
ha/data chore: checkpoint all prior work for clean state 2026-06-04 13:04:16 +00:00
raft chore: checkpoint all prior work for clean state 2026-06-04 13:04:16 +00:00
src fix(libxce): endpoint reference count — kill teardown-vs-dispatch UAF (bug-1298, task 5.8) 2026-06-30 14:24:47 +00:00
.clang-format reformat code and job array 2025-11-07 16:14:27 +08:00
.gitignore checkpoint: bug-851 root cause + raft TLA+ conformance spec family 2026-06-21 14:02:15 +00:00
.mcp.json checkpoint: bug-851 root cause + raft TLA+ conformance spec family 2026-06-21 14:02:15 +00:00
.opencode.json checkpoint: bug-851 root cause + raft TLA+ conformance spec family 2026-06-21 14:02:15 +00:00
CLAUDE.md chore: baseline snapshot — prior-session work + ha-consistency-invariants spec family 2026-06-11 13:21:50 +00:00
package-lock.json checkpoint: bug-851 root cause + raft TLA+ conformance spec family 2026-06-21 14:02:15 +00:00
package.json checkpoint: bug-851 root cause + raft TLA+ conformance spec family 2026-06-21 14:02:15 +00:00
README.md save works 2026-03-03 16:49:26 +08:00
uninstall-code-review-graph.sh checkpoint: bug-851 root cause + raft TLA+ conformance spec family 2026-06-21 14:02:15 +00:00

1. commit 规则

  • 每个人 fork 自己的 branch, 从自己的 branch 做 PR,review 完再 commit

2. code format

2.1. C

推荐使用 clang-format,公共配置放在源码里面 xce/.clang-format

(理论上直接使用源码里面 xce/.clang-format 文件格式不会变)

2.1.1. vscode 可以在配置中加上如下内容

"C_Cpp.clang_format_style": "WebKit",
"C_Cpp.clang_format_fallbackStyle": "WebKit",

2.1.2. vim & emacs

clang-format -style="{BasedOnStyle: webkit}" -i XX.c

2.2. golang

使用默认 gofmt

3. build environment and build (example of ubuntu)

3.1 build environment

  • Install nix package management tool
sh <(curl -L https://nixos.org/nix/install) --daemon
  • Edit /etc/nix/nix.conf to make sure
experimental-features = nix-command flakes
sandbox = true
sandbox-fallback = false
substituters = https://mirrors.ustc.edu.cn/nix-channels/store https://cache.nixos.org https://cache.nixos.org/
trusted-users = root <your account>

make sure that you have restarted nix-daemon service after you have changed /etc/nix/nix.conf

  • Install socat and config ssh (for clone by ssh protocol)
nix profile add nixpkgs#socat

.ssh/config

Host gitea.shenrs.eu
	HostName gitea.shenrs.eu
	IdentityFile ~/.ssh/id_ed25519
	ProxyCommand socat - openssl-connect:gitea.shenrs.eu:2022,snihost=gitea.shenrs.eu,verify=0

3.2 checkout source code

3.3 build (for package and release)

cd xce/src

# for build debug version
nix build --option sandbox false .#xcecore_debug

# for normal build
nix build --option sandbox false .#xcecore

You can find the generated binaries at =result= directory

3.4 build (for daily develop)

cd xce/src
nix develop

# using meson to generated build configuration (debug and address sanitize)

meson setup build --buildtype=debug -Db_sanitize=address

# run meson to build
meson compile -C  build

# The generated files will be in build/

3.5 build AppImage package

cd xce/src
nix bundle --bundler github:ralismark/nix-appimage --option sandbox false .#xce

This will create all in one AppImage file which contains everything for package delivery.

4. misc

4.1. Windows remap ctrl and alt key

create a reg file, e.g. remapkey.reg

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Keyboard Layout]
"Scancode Map"=hex:00,00,00,00,00,00,00,00,05,00,00,00,38,00,1d,00,1d,00,38,00,38,e0,1d,e0,1d,e0,38,e0,00,00,00,00

then double click remapkey.reg to import it. Restart OS.