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Rongsong Shen
6d510d8cf4
When the (still-default-OFF) peer-control dispatch flag is ON, raft_cb_become_follower runs as a vtask pool worker and frees every peer vote-ep while other pool workers may still hold those eps' data — a UAF (bug-1197). This makes that path quiescence-safe so the flag can later be flipped ON (deferred to the 4.x prod-flip gate; production stays OFF here). Mechanism (no libxce-wide endpoint refcount; reuses the existing per-ep FIFO + busy serialization): - Deferred teardown-as-vtask: the loser loop, when dispatch is ON and the pool is wired, does per vote-ep endpoint_mark_tearing_down -> iomgr_unmonitor -> enqueue a VTASK_IO/VTASK_LIVENESS teardown vtask bound to that ep. Per-ep busy FIFO makes it run strictly after any in-flight/queued same-ep peer-control vtask; the body NULLs iod->ep before endpoint_fini+free(ep) to disarm run_task's post-body endpoint_unblock_tasks (which would touch the freed ep->lock). OFF / pool-unwired path is byte-for-byte the legacy endpoint_fini. - RCU-like drain closes the dispatch/teardown TOCTOU window: new _Atomic int endpoint_t.dispatch_inflight (+ tearing_down:1 bit). The ON dispatch brackets its flag-check+enqueue with fetch_add/fetch_sub (seq_cst); endpoint_mark_tearing_down sets the flag under ep->lock, releases, then spins until dispatch_inflight drains to 0. So every dispatch that read the flag false finishes its enqueue before mark returns (FIFO-before the teardown vtask); any later dispatch reads the flag set and drops the packet. ep->lock is deliberately NOT held across the enqueue (it inverts with the taskq lock in vtask_eligible); the counter is the lock-free handshake. Drain is bounded: the held window is just a calloc + non-blocking enqueue on the single io_worker. Still open before the production flag flip (4.x): the borrowed-ep race in snapshot_lane_fn/configpush_lane_fn is distinct (slowlane thread vs io_worker RDHUP teardown, not the vtask-pool FIFO) and needs its own per-standby-ep discipline. Tests: test_ha_vep_teardown.c — 5 ASan tests (ordering, late-event drop, run_task unblock disarm, OFF-path unchanged, deterministic mark-drains-inflight-dispatch). xcelib_test 282/0; controller_unit_test EXIT=0; ASan-clean. Adversarial cpp-review: no CRITICAL/HIGH; handshake formally sound, flag-ON path race-free. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01S6fDCtXkkEgupu7rUah1y2 |
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|---|---|---|
| .claude | ||
| .kiro | ||
| .wolf | ||
| docs/superpowers/plans | ||
| ha/data | ||
| raft | ||
| src | ||
| .clang-format | ||
| .gitignore | ||
| .mcp.json | ||
| .opencode.json | ||
| CLAUDE.md | ||
| package-lock.json | ||
| package.json | ||
| README.md | ||
| uninstall-code-review-graph.sh | ||
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.