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WalkthroughIntroduces in-flight DevServer bundle tracking on VirtualMachine, makes has_terminated atomic and published earlier during destroy, adds event-loop guards to drop tasks on terminated VMs, conditionally leaks DevServer/VM during shutdown when bundles are in flight, adds a uWS thread-exit leak helper, and an ASAN test. ChangesAsync DevServer bundle teardown safety
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⚠️ Outside diff range comments (1)
src/jsc/VirtualMachine.rs (1)
4504-4562:⚠️ Potential issue | 🟠 Major | ⚡ Quick winSet
has_terminatedbefore tearing down the event loops.
enqueue_task_concurrent{,_batch}only starts dropping work after this flag flips. Publishing it afterregular_event_loop.deinit()/macro_event_loop.deinit()leaves a race where a WorkPool thread can still enqueue into a partially torn-down loop duringdestroy(), which reopens the shutdown UAF window this PR is trying to close.Suggested fix
pub fn destroy(&mut self) { + self.has_terminated + .store(true, core::sync::atomic::Ordering::Release); + self.regular_event_loop.deinit(); self.macro_event_loop.deinit(); @@ - self.has_terminated - .store(true, core::sync::atomic::Ordering::Release); }🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the rest with a brief reason, keep changes minimal, and validate. In `@src/jsc/VirtualMachine.rs` around lines 4504 - 4562, The destroy() method currently flips has_terminated after tearing down regular_event_loop.deinit() and macro_event_loop.deinit(), which allows enqueue_task_concurrent / enqueue_task_concurrent_batch to race and push work into partially torn-down loops; move the has_terminated.store(true, Ordering::Release) to the top of destroy() (immediately before or as the first action) so the flag is published before calling regular_event_loop.deinit() and macro_event_loop.deinit(), ensuring worker threads stop enqueuing during shutdown.
🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Inline comments:
In `@src/runtime/bake/DevServer.rs`:
- Around line 3440-3449: The VM in-flight counter (vm.pending_async_bundles)
must be incremented before any ParseTasks/other bundle tasks are submitted so
WebWorker::shutdown cannot observe a zero window; move the increment so it runs
prior to calling start_from_bake_dev_server(...) / queuing ParseTasks, rather
than after; keep the corresponding decrement in finalize_bundle unchanged and
ensure the increment uses the same VM reference (vm()) as before so
pending_async_bundles accurately reflects tasks in-flight during task
submission.
In `@test/bake/deinitialization.test.ts`:
- Around line 145-149: Replace the weak ASAN substring check with an explicit
empty-stderr assertion: after resolving Promise.all([proc.stdout.text(),
proc.stderr.text(), proc.exited]) use expect(stderr).toBe("") (asserting the
child emitted nothing on stderr) and ensure the exitCode assertion
(expect(exitCode).toBe(0)) remains last; update the assertions that reference
stdout, stderr, and exitCode in this test (variables stdout, stderr, exitCode)
accordingly.
---
Outside diff comments:
In `@src/jsc/VirtualMachine.rs`:
- Around line 4504-4562: The destroy() method currently flips has_terminated
after tearing down regular_event_loop.deinit() and macro_event_loop.deinit(),
which allows enqueue_task_concurrent / enqueue_task_concurrent_batch to race and
push work into partially torn-down loops; move the has_terminated.store(true,
Ordering::Release) to the top of destroy() (immediately before or as the first
action) so the flag is published before calling regular_event_loop.deinit() and
macro_event_loop.deinit(), ensuring worker threads stop enqueuing during
shutdown.
🪄 Autofix (Beta)
Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
- Create a new PR with the fixes
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📒 Files selected for processing (6)
src/jsc/VirtualMachine.rssrc/jsc/event_loop.rssrc/jsc/web_worker.rssrc/runtime/bake/DevServer.rssrc/runtime/server/mod.rstest/bake/deinitialization.test.ts
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All three issues from my earlier passes are addressed in 13be3fb and 55bd290, and I have nothing further — but this is cross-thread unsafe Rust touching VM/worker teardown and an intentional-leak lifetime strategy, so it's worth a human set of eyes before merge.
Extended reasoning...
Overview
This PR fixes a use-after-free where tearing down a worker VM or DevServer while async bundle ParseTasks are still running on the shared WorkPool freed memory those tasks dereference. The fix is to detect the in-flight state (pending_async_bundles counter) and leak the VM box / DevServer box / bundle state rather than free it, plus turn post-termination concurrent enqueues into no-ops. Touches VirtualMachine.rs, event_loop.rs, web_worker.rs, DevServer.rs, server/mod.rs, and adds an ASAN-gated regression test.
I previously flagged three issues (non-atomic has_terminated data race; self.execution_context_id read after dispatchExit; partial leak of current_bundle leaving bv2's inline-transpiler borrows dangling). All three were fixed in 13be3fb and 55bd290, and the current diff reflects those fixes correctly — has_terminated is now AtomicBool with Release/Acquire, execution_context_id is snapshotted before step 4, and both DevServer drop sites now route through drop_or_leak which leaks the whole box. The bug-hunting system found nothing further on the latest revision.
Security risks
No new attack surface — this is internal teardown ordering. The risk class is memory safety (UAF / data race), which the PR is fixing rather than introducing. The mitigation deliberately leaks memory on a rare teardown-during-bundle path, which is a resource trade-off, not a security exposure.
Level of scrutiny
High. This is unsafe Rust manipulating raw pointers across threads in the VM/worker/event-loop teardown path, with subtle ordering invariants (step-4/step-5 contract in shutdown, vm_lock publish/unpublish, the Box<DevServer> self-borrow via bv2). The "leak instead of free" strategy is sound but unusual enough that a maintainer should confirm it's the right call vs. e.g. a future cancellation/join mechanism, and that all owner drop sites are covered by drop_or_leak.
Other factors
The PR has iterated through three rounds of feedback and the author's responses were precise (including a correct push-back on my reachability analysis re: on_pending_request). The ASAN regression test is well-constructed. CI build #59837 is in progress for the latest commit. Given the complexity and the criticality of the code path, I'm deferring rather than approving.
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All three issues I raised earlier are addressed and the bug hunter found nothing new, but this is cross-thread VM-teardown / deliberate-leak code on a production crash path — worth a human pass on the leak doctrine and the new release-build no-op in enqueue_task_concurrent.
Extended reasoning...
Overview
This PR fixes a use-after-free where terminating a worker (or dropping a DevServer) while a Bake bundle still has ParseTasks running on the shared WorkPool freed memory those tasks dereference. The fix introduces VirtualMachine::pending_async_bundles (a same-thread Cell<u32>), makes has_terminated an AtomicBool, has WebWorker::shutdown leak the VM/env/arena when the count is nonzero, has DevServer::drop_or_leak leak the whole Box<DevServer> when a bundle is in flight, and turns EventLoop::enqueue_task_concurrent{,_batch} into a no-op on a terminated VM (previously a debug-only panic). An ASAN-only regression test sweeps worker.terminate() timing against an in-flight bundle.
The PR went through three fix-up rounds: has_terminated made atomic and execution_context_id snapshotted before dispatchExit (13be3fb), the DevServer leak widened from just current_bundle to the whole box at both owner drop sites (55bd290), and the test's stderr assertion tightened plus the has_terminated store moved before event-loop deinit (2bf65f0). One CodeRabbit suggestion (move the counter increment before task submission) was declined with sound reasoning — the counter is same-thread-only and shutdown cannot preempt start_async_bundle.
Security risks
None identified. This is internal memory-lifecycle management; no auth, input parsing, or external-data handling is touched. The deliberate leaks are bounded (one VM box + one DevServer box per terminate-mid-bundle event, which is a teardown path).
Level of scrutiny
High. This is unsafe Rust on a critical path — VM destruction, worker shutdown sequencing, cross-thread atomic ordering, and a behavioral change to a hot concurrent-enqueue path that now silently drops tasks in release builds (formerly only a debug assertion). The fix strategy is intentional leaking, which is a design decision a maintainer should sign off on even though it mirrors the Zig precedent. The fact that it took three rounds of corrections (two of which were genuine UB I flagged) to converge is itself a signal that the reasoning is subtle.
Other factors
All my prior inline comments are resolved and verified in the current diff. The bug-hunting pass on the latest revision found nothing. The ASAN test is well-constructed and the author verified 4/4 green after the final stderr-assertion fix. The one open CodeRabbit thread was correctly declined. CI on 55bd290 showed the test failing on x64-asan; 2bf65f0 was pushed specifically to address that — I'd want to see the new CI result, but that's orthogonal to the code review itself. Given the criticality and the iteration history, a human reviewer (the suggested Jarred-Sumner / dylan-conway) should confirm the leak doctrine and the enqueue_task_concurrent semantics change are acceptable for all callers, not just Bake.
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All prior review feedback has been addressed and the bug-hunting pass is now clean, but given this touches cross-thread VM/worker teardown and introduces a deliberate-leak doctrine for in-flight bundle state, it warrants a human sign-off.
Extended reasoning...
Overview
This PR fixes a production use-after-free (four Sentry crash signatures, all with generate_react_refresh_import_hmr on the stack) caused by tearing down a worker VM or DevServer while async bundle ParseTasks are still running on the shared WorkPool. It touches six files: VirtualMachine.rs (new pending_async_bundles: Cell<u32> counter; has_terminated promoted to AtomicBool), event_loop.rs (enqueue_task_concurrent{,_batch} now no-op on a terminated VM instead of debug-panicking), web_worker.rs (shutdown() leaks the VM/env/arena when bundles are in flight), DevServer.rs (in-flight tracking, drop_or_leak(), transpiler-drop skip), server/mod.rs (routes both DevServer drop sites through drop_or_leak), and a new ASAN-only regression test.
The PR has gone through three rounds of automated review. Earlier rounds flagged (1) a data race on the non-atomic has_terminated field, (2) a self.execution_context_id read past the dispatchExit may-be-freed point, and (3) the partial-leak in Drop for DevServer leaving the leaked bv2's inline-transpiler borrows dangling — all three were fixed in 13be3fb and 55bd290. CodeRabbit's increment-ordering concern was correctly declined (same-thread Cell, no observable window), and its stderr-assertion nit was addressed in 2bf65f0. The final commit 80992d0 disables LSan for the test fixture (the fix deliberately leaks). All inline comments are resolved and the current bug-hunting pass found nothing.
Security risks
None in the conventional sense — no auth, crypto, input-parsing, or permission surface is touched. The risk profile here is memory safety and concurrency correctness in runtime-critical code: Release/Acquire ordering between the worker thread's has_terminated store and WorkPool threads' loads, the soundness argument for reading pending_async_bundles (a non-Sync Cell) only on the VM's own thread, and the completeness of the leak set (VM box, env loader/map, uws loop, arena, DevServer box, transpilers, bundle heap). Getting any of these wrong reintroduces the UAF or a TSan-visible race.
Level of scrutiny
High. This is production-critical runtime code on a hot teardown path, with subtle cross-thread reasoning and a deliberate-leak design choice that diverges from (and per the author's reply, goes beyond) Zig parity. The fix's correctness depends on invariants documented in comments (e.g. "start_async_bundle runs synchronously on the VM thread; shutdown only runs after spin() exits") that a human familiar with the bundler/VM lifecycle should confirm. The earlier review rounds surfaced three real soundness issues, which suggests this code is easy to get subtly wrong.
Other factors
The new test is ASAN-only with detect_leaks=0 (necessarily — the fix leaks by design), and the author reports 3/3 ASAN failures pre-fix → 3/3 passes post-fix plus green on the broader bake/HMR/stress suites. The reasoning in the PR description and inline comments is thorough and the iterations were responsive. Nonetheless, the combination of (a) cross-thread atomics with documented memory-ordering pairings, (b) a new VM-level counter whose lifecycle must stay in sync with bundle start/finalize, (c) two owner-side drop sites now routed through a leak helper, and (d) an early-return added mid-shutdown() step 5, is the kind of change a maintainer should read end-to-end rather than rely on automated review alone.
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CI status: the debian-13-x64-asan lane — the one that exercises the new regression test — passes as of 80992d0. The only failures on build 59863 were three macOS test lanes with status Expired (Buildkite agents never picked up the jobs; the suites never ran — 72 other lanes green). Pushed one empty retrigger (a676684) for those; everything the diff touches is verified green. Ready for maintainer review. |
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The c64034b fix for the LoopCleaner TLS-destructor issue looks correct and I have no further findings, but this is intricate cross-thread lifetime management (intentional leaks spanning Rust/C++ in VM/worker/uws teardown) that warrants a maintainer's eyes.
Extended reasoning...
Overview
This PR fixes a production use-after-free cluster (four Sentry signatures) by ensuring that when a worker VM or DevServer is torn down while a Bake async bundle still has ParseTasks running on the shared WorkPool, the state those tasks reach (VM box, event loop, env loader/map, uws loop, worker arena, DevServer box, bundle heap) is leaked rather than freed. It touches 9 files across the Rust runtime (VirtualMachine, EventLoop, WebWorker::shutdown, DevServer drop, Server deinit), the uWS C++ loop (Loop.h, libuwsockets.cpp), and adds an ASAN-only regression test.
Review history
I reviewed this PR three times and each round found a real correctness issue, all of which were fixed:
has_terminatedwas a plainboolwritten/read across threads → nowAtomicBoolwith Release/Acquire; and a debug-onlyself.*read past thedispatchExitfreedom point → now snapshotted.- Leaking only
current_bundleleftbv2's borrows of the inline transpilers dangling when theBox<DevServer>was deallocated → nowdrop_or_leakleaks the whole box at both owner drop sites. - The early-return leak path didn't actually leak the uws loop because the C++
thread_local LoopCleanerdtor still ran via__cxa_thread_atexit→ now disarmed vialeakLoopAtThreadExit().
The latest commit (c64034b) correctly implements the third fix: getLazyLoop().cleanMe = false keeps the loop non-null (so straggler wakeup()s touch live memory) while making the TLS dtor a no-op. The stale comment about glibc skipping the dtor was also corrected. The bug hunting system found no new issues on this revision.
Security risks
None in the conventional sense — no auth, input parsing, or external data handling. The risk profile is memory-safety/concurrency correctness: an error here manifests as UAF/crash rather than exploit surface.
Level of scrutiny
High. This is production-critical VM lifecycle and worker teardown code, with subtle cross-thread lifetime reasoning, intentional memory leaks as a correctness strategy, atomics ordering that matters, and a Rust↔C++ boundary (__cxa_thread_atexit semantics) that already tripped up a pre-existing code comment. The fix went through three substantive revisions during bot review alone. The has_terminated Release store also moved earlier in VirtualMachine::destroy(), which subtly changes ordering for any other concurrent enqueue path.
Other factors
- All review threads (mine and CodeRabbit's) are resolved; the one CodeRabbit "critical" was correctly declined (same-thread
Cell<u32>, no observable window). - The ASAN regression test is well-constructed (timing sweep, macro to lengthen parse, LSan disabled with justification, stderr filtered to known-benign progress lines).
- CI: the ASAN lane that exercises the new test passed; remaining failures were Buildkite agent expirations on macOS, retriggered.
- The author has flagged it ready for maintainer review.
Given the complexity and the criticality of the touched paths, this should not be auto-approved.
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Final CI status on c64034b: 71 lanes pass, 0 test failures. The only red checks are three macOS lanes marked Expired — Buildkite agents never picked the jobs up (second consecutive build with macOS fleet starvation; the same suites pass on every other platform). The lane that exercises this PR's regression test — debian-13-x64-asan-test-bun — passes (12m26s). All four bot-review rounds are addressed and their threads resolved; claude[bot]'s final pass found nothing further and recommends human sign-off for the leak-on-forced-teardown approach, which this PR inherits from the Zig implementation's Ready for maintainer review/merge — the expired macOS lanes just need agents (or a manual retry in Buildkite). |
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CI addendum for build 59890's late-running |
…are in flight
Terminating a VM (worker.terminate()) or dropping a DevServer while its
async bundle still has ParseTasks running on the shared WorkPool freed
memory those tasks dereference:
- WebWorker::shutdown deallocated the VirtualMachine box; the bundle's
AnyEventLoop::Js handle points at vm.event_loop (a value field of that
box), so a straggler's result enqueue read freed memory
(ASAN: heap-use-after-free in EventLoop::vm_ref via
enqueue_task_concurrent from run_from_thread_pool).
- Drop for DevServer let current_bundle's field drop free the BundleV2,
the bundle mi-heap (which arena-owns the ParseTasks themselves), and
the AstAllocState. Zig deliberately leaked this state ("impossible to
de-initialize this state correctly"); the port only kept the debug
assert and freed anyway. In release the stray writes land in recycled
mimalloc blocks and surface later as scattered segfaults inside parser
codegen, e.g. generate_react_refresh_import_hmr.
Those tasks can be neither cancelled nor waited for once the event loop
stops draining (the completion that ends the bundle can never run), so
teardown now leaks instead of freeing: DevServer::drop leaks
current_bundle, and WebWorker::shutdown leaks the VM (plus env/loop/
arena) when VirtualMachine::pending_async_bundles - a new same-thread
counter maintained by start_async_bundle/finalize_bundle - is nonzero.
Concurrent enqueues on a terminated VM become no-ops instead of a
debug-only panic, so stragglers finish harmlessly.
Regression test (ASAN-only): sweeps worker.terminate() timing against a
dev server bundling 24 JSX components and a bundler macro; 3/3 ASAN
use-after-free before, 3/3 clean after.
…atchExit Review follow-ups: the leak-the-VM branch stores has_terminated on the worker thread while WorkPool threads read it in release builds now, so the plain bool was a data race - use AtomicBool with Release/Acquire. The leak-path log! read self.execution_context_id past the documented 'this may be freed' point; snapshot it with the other locals instead.
The leaked in-flight bv2 borrows the three transpilers stored inline in the Box<DevServer> (see CurrentBundle::bv2), so leaking just the bundle still left those borrows dangling once Drop destructed the transpilers and the owner freed the box. Route both owner drop sites (Server::deinit_if_we_can and NewServer::drop) through DevServer::drop_or_leak, which leaks the whole box while has_in_flight_bundle(), and skip the transpiler destructors in Drop as a backstop for any other drop path.
…derr in test destroy() used to flip has_terminated after deiniting both event loops; with the enqueue guard now live in release builds, publish the flag first so a late concurrent producer no-ops instead of pushing into a partially torn-down loop. The regression test now asserts stderr is empty after stripping the dev server's bundle-progress lines (the only output a passing run emits) instead of grepping for the sanitizer marker.
The fix deliberately leaks the worker VM and bundle state when a dev server bundle is in flight at terminate() - there is no way to cancel or wait for its WorkPool tasks. LSAN on the ASAN lanes reports those intentional leaks (184 bytes: source-code printer, worker map entries, block stores) at child exit and fails the empty-stderr assertion. Disable leak detection for the child only; heap-use-after-free detection is ASAN proper and still aborts the unfixed build.
Skipping bun_uws::on_thread_exit() does not leak the loop by itself: the C++ thread_local LoopCleaner destructor runs at thread exit via __cxa_thread_atexit regardless of the unwind-free return path, and would us_loop_free() a loop that a straggler ParseTask - one that loaded has_terminated == false just before the Release store - may still wakeup(). Add Loop::leakLoopAtThreadExit() (cleanMe = false), export it as bun_leak_loop_at_thread_exit, and call it in the leak branch. Also correct the stale comment claiming the destructor is skipped on glibc (c-bindings.cpp documents the opposite).
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CI status after the rebase (build 61330, sha 84e5d82): debian-13-x64-asan-test-bun passes (8m42s — the lane exercising this PR's regression test), all build lanes pass. The red test lanes (alpine x3, windows-aarch64, darwin) all fail on |
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Stale PR review: keep open, rework. The problem is still open on main. A Worker teardown does not wait for dev server ParseTasks, and it does not cancel them. Main has no The current diff is not the wanted shape:
The wanted shape puts dev server bundles through the teardown path that
With either option, the teardown returns only after the tasks come back. The DevServer can then be freed normally, and the The reach is low. The four Sentry ids in the PR body no longer resolve. A 90-day crash search for the |
… and CLI (#46021) ### What does this PR do? Hardening. This collects the open pull requests that fix a crash in Bun into one change, and fixes about 20 more crashes that had no pull request. "Crash" here means a segfault, a Rust panic, an abort, a failed assertion, memory corruption that a sanitizer reports, a native stack overflow, or an exception that ends the process and that the program can't catch. With this PR those cases throw a normal error, print a normal CLI error and exit 1, or just work. 306 pull requests are included: 227 whole, and 79 cut down to the crash fix where the rest was a refactor, a feature or a behavior change. Each one was checked against current `main` first. 45 more turned out to be fixed already, and 17 were duplicates. The full list is at the bottom. #### Crashes you could hit in normal use - **`bun build` with macros and a `.env` file crashed at random.** In a repro with many macro modules, more than a third of the builds crashed. Now 3,000 of 3,000 produce the right bundle. (#45960) - **`bun run` and `bunx` aborted if a signal arrived while the child was being spawned.** (#38926, #45965) - **`bun build --compile ./index.js ./public/*` panicked** if an embedded file's name wasn't valid UTF-8. - **A truncated or corrupted compiled executable** died with SIGBUS or a panic at startup. It now prints an error. (#31787, #38251, #41360) - **Dev server:** several `Option::unwrap()` panics after a failed or deleted import (#38046, #44744, #44746), a segfault when an `onLoad` plugin throws while another bundle is queued, a request that hung and then panicked with `bundle active`, and `server.stop()` that never resolved after a client aborted a waiting request. - **`Bun.serve`:** `server.fetch(url, { headers: new Headers() })` followed by a GC segfaulted (#40888). Routes were used after free after `server.reload()` with `tls.serverName` (#38636). - **`text()` and `json()` on a stream of string chunks** could abort the process, a regression in 1.4.0. (#44269) - **`Bun.Transpiler` with `exports.eliminate` or `exports.replace`** aborted on `export default 1` and on most re-export clauses. (#44137) - **A decorated `declare` field in a class expression** with `experimentalDecorators` panicked. (#38095) - **YAML and JSON5 files with a key that isn't a string** panicked with `--no-bundle` and in `Bun.Transpiler`. (#41827) - **`Bun.FileSystemRouter`:** reading `.params` segfaulted when a rejected route candidate left its parameters behind. (#39290, #39291) - **Native addons that call `uv_async_*`, `uv_timer_*`, `uv_idle_*`, `uv_prepare_*`, `uv_check_*`, `uv_queue_work` or `uv_cwd`** aborted with "unsupported uv function" on Linux and macOS. They're implemented now. (#36609, #39652, #39892) - **`--watch` and `--hot`** panicked when the system was out of inotify instances or file descriptors, or when the reload `exec` failed. They print an error now. (#39629, #39975, #44837) - **Paths longer than the path buffer** panicked in `bun install`, the resolver, the bundler, `--compile`, `tsconfig.json` `paths` and `baseUrl`, `package.json` `main` and `sideEffects`, `bun run --filter`, `bun pm diff`, source maps and snapshots. They're ordinary errors now, or they work. (#36340, #37529, #39104, #39650, #43067) - **A Worker that creates a `ShadowRealm` and imports `node:worker_threads` in it** segfaulted. - **`structuredClone` or `postMessage` of an X25519 key** gave an object that aborted the process when read. (#45624) - **`node:stream` web adapters and `node:http2`** could end the process with an exception that no handler could catch. (#45076, #45975) - **Windows:** a watcher panic in a burst of file changes (#44344), a segfault after the machine resumes from sleep (#33015), crashes in the shell's pipe reader (#39638, #43606), and addons that import from `node.exe` without the delay-load hook (#35618). Most of the rest needs unusual input: strings near the 2 GiB limit, buffers that another thread or a getter resizes or detaches in the middle of a call, `worker.terminate()` at a bad moment, running out of memory or file descriptors, very deep nesting, or hostile arguments to `bun:ffi`, `node:vm` and `bun:sqlite`. #### Behavior changes Things that didn't crash before and behave differently now: - `new` on native functions that aren't constructors throws a `TypeError`, as in Node: `util.types.*`, `buffer.isAscii`, `isUtf8`, `transcode`, `resolveObjectURL`, `bun:jsc` exports, `cc()` symbols. It used to return the call's result. They also stop printing as `[class hostname]`. (#34575) - `` $`cmd` `` throws `ERR_INVALID_ARG_VALUE` if an environment variable's name or value contains a NUL byte. It used to cut the value at the NUL. (#44981) - `cc()` functions throw a `TypeError` for arguments that used to reach C as garbage, and `read.*(ptr, NaN)` throws. (#37989, #38057, #40773) - As PID 1, `bun` exits with 128 + the signal number on Ctrl+C or `docker stop`. (#38877) - A `NODE_MODULE` addon that's already loaded by the main thread throws `ERR_DLOPEN_FAILED` when a live Worker loads it too, as in Node. (#39968) - An exception from a `node:vm` context reaches `uncaughtException` handlers. (#39992) `vm.constants.DONT_CONTEXTIFY` returns the real global proxy. (#34623) - `createPrivateKey` rejects an EC JWK whose private value doesn't match its public point. (#33752) - `@dec static {}` is a syntax error, as in TypeScript and esbuild. (#44883) - `clearTimeout` ignores 0 and negative ids, and timer ids no longer wrap. (#44771) - HEAD for a `Response` whose body is an S3-backed `Blob` reports the length that GET sends. (#44734) - `bun:sqlite` and `node:sqlite`: if `iterate()` left a write unfinished on a connection that has a hook, a user function or an authorizer, the write is finished on the connection's next call instead of during garbage collection. If the database is gone too, it's rolled back. - `bun test --bail` runs exit listeners and closes SQLite databases. (#39010) - Dev server: a request for a client script waits while a bundle is in flight (#42733), query strings reach framework routes (#33232), and a request gets a 500 instead of hanging when plugins fail (#36812). #### File formats - `.jsc` bytecode files get a 24-byte footer so they can be verified before decoding. Files from an older Bun are ignored and the source is parsed instead. (#39396) - `node:vm` `cachedData` gets an 8-byte checksum. A blob from an older Bun is rejected, which the API allows. (#32839) - The built-in modules section of a compiled executable changes from format 1 to 2 and carries an engine stamp. (#44907) #### Performance Measured in instructions per operation on release builds of this branch and its base, with an A/A run for the noise floor (0.0 to 0.2 %). No change: `Bun.serve`, `node:http`, WebSocket echo and publish, `bun build` of 3,807 modules, `bun run` with 2,000 imports, `readdir` / `Glob` / `fs.cp` over 23,689 entries, startup and RSS. The binary grows by 176 KB (0.17 %). | Faster | Instructions | | --- | --- | | WebSocket echo of a 1 MB non-ASCII text message | −72 % | | `Bun.inspect` of a large non-ASCII string | −39 % | | `Bun.markdown.html` on large non-ASCII input | −33 % | | `` $`cmd` `` with 300 environment variables | −6 % | | `fs.readSync` | −5 % | | `TextEncoder.encodeInto`, short ASCII strings | −4 % | | async `crypto.pbkdf2`, 16-byte inputs | −17 % | | Slower | Instructions | Why | | --- | --- | --- | | `cc()` calls | +5 to +51 per call | Argument count and type checks, and a check for `close()` (#37989, #38057, #43802, #44921). `dlopen()` calls don't change | | `process.env.X = v` | 38 → 593 per write | Writes aren't cached. Reads don't change (#38871) | | async `crypto.pbkdf2`, inputs of 1 KB or more | +4 to +9 % | Password and salt are copied (#40554) | | `bun build` with an object `--define` used thousands of times | +4.5 % | The object is copied per use (#45969) | #### Not included - Fixes that need a WebKit change: #39967, #42534, #42982, #43764, #43786, #44226. #42185 too: a typed array that has no `ArrayBuffer` yet can't be pinned, so `view.buffer.transfer()` during an async call can still free its bytes. Creating the `ArrayBuffer` up front costs 7 to 12 % on every async `fs` call, so the fix belongs in JSC: an `ArrayBuffer` created while the view is borrowed should start out pinned. - #45442 (`calc()` sums as a flat list): it changes minified output for real stylesheets to survive a `calc()` with 25,000 terms. It deserves its own review. - #40023 (Windows event loop redesign), #29928 (Windows exit path), #40534, #43963, #39571, #42904, #42834, #36355, #43266: refactors or features whose crash is already covered or isn't a crash. - The pull requests marked *(crash fix only)* below should stay open for their other half. ### How did you verify your code works? - **Tests.** Every fix has a test that fails on `main` (a release or an ASAN build) and passes on this branch, except where that isn't practical: code that only runs on Windows or macOS, inputs that need several GB of memory, and a few rare races. Those were checked by hand or by reading. - **Stored repro scripts.** 230 crash repros ran on release and ASAN builds of this branch and of `main`, side by side. Release: 88 no longer crash. ASAN: 106 no longer crash. None crashes that didn't before. What still crashes needs WebKit, is SQLite's own bug, or isn't a crash. The ASAN number is from a later commit than the release number. - **Dev server.** Because one fix makes requests wait, 2,171 generated programs ran random interleavings of edits, build errors, failing plugins, reloads, stops and disconnects with about 120,000 requests. No request hung, was answered twice or got a stale body. `main` hung in 82 of 1,161 programs. This also found the four dev server bugs listed above. - **Path helpers.** 336,000 boundary cases with buffers of exactly the computed size, and 12,003 random calls through 30 JS APIs on an ASAN build, compared with `main`. No sanitizer report, and the results match wherever `main` doesn't panic. - **What worked on 1.4.3 still works.** Reviewers compared behavior with 1.4.3 and took out what changed it: for example an output directory layout change for 9 or more entry points, a `server.reload()` change, and a changed error message for `import("file:///50%deposit.ts")`. - **Not run locally:** the Windows, macOS and FreeBSD code paths. CI compiles and tests them. ### Included pull requests **Bundler, transpiler, CSS, macros** (33) - #33881 bundler: allocate wrapper_ref for CommonJS modules with no non-hoistable statements - #35055 Bun.build plugins: handle filter RegExp flags beyond i/m/v - #37769 bundler: fail the build instead of panicking when the bundle thread cannot create its waker - #37784 bundler: copy inlined env values into the define arena, and give each Bun.build its own env copy *(crash fix only)* - #37858 bundler: fail the build instead of panicking when a plugin answer string cannot be converted - #38046 bun build --server-components: require the bun target and reject directives without a framework *(crash fix only)* - #38095 js_parser: fix panic on decorated declare/abstract fields in class expressions with experimentalDecorators - #38966 bundler: keep deep CSS, export star and composes graphs from overflowing the linker's stack - #38984 bundler: stop an export star ambiguity that loops back into a re-export chain from overflowing the stack - #39113 css: reject stylesheets of 2 GiB or more instead of aborting on an int cast - #39396 bundler: frame .jsc bytecode sidecars and verify them before decoding - #39855 bundler: join the work still on the pools before the bundle is torn down *(crash fix only)* - #41157 dev server: leave out an html link to a cached json module instead of panicking, and mark a new placeholder file stale - #41801 css: decode ill-formed UTF-8 to U+FFFD before tokenizing *(crash fix only)* - #41827 bundler: handle YAML and JSON5 keys that are not strings instead of panicking - #42242 js_parser: compress symbol link chains when following merged declarations - #42387 bundler: check receivers on the Bun.build plugin object and freeze its filters during a build - #42413 Bounds-check the InternalSourceMap window reader - #42657 macros: keep visited values alive so a reused address does not get another value's Expr - #43330 transpiler: do not print an empty `var` for a data file with no named export - #43355 bundler: fix "The memory limit has been exceeded." on large HTML entries - #43658 react-compiler: fix skipped functions and build aborts for dead code in a try body *(crash fix only)* - #44137 js_parser: fix four crashes of exports.eliminate and exports.replace - #44467 js_parser: replace skipped expressions with E::Missing and skip argument checks after a stack overflow - #44662 js_parser: walk binary chains on the heap and check the stack when rewriting decorated #private accesses - #44712 json5: reject sources of 2 GiB or more before parsing instead of aborting on an int cast - #44864 js_parser: walk conditional chains in import()/require() and define keys in a loop - #44883 js_parser: reject a decorator on a class static block, keep decorators out of the body of `declare global` *(crash fix only)* - #45045 Fix a segfault in new Bun.Transpiler(): re-point options.log after the constructor moves its Log - #45604 css: keep a url() in an at-rule prelude as written, and never print the resolved path of a url() *(crash fix only)* - #45748 bundler: put --banner/--footer in the bytecode ESM module record (flags from a parse, entries from JSC) *(crash fix only)* - #45960 macros: give each parse-worker macro VM its own env loader - #45969 js_parser: copy object and array defines per use, and copy the list of a lone JSX spread object *(crash fix only)* **`bun build --compile` and standalone executables** (3) - #31787 Don't crash at startup when a standalone executable's embedded graph is corrupted *(crash fix only)* - #38251 compile: exit with an error instead of SIGBUS when a standalone executable is truncated - #41360 standalone: check every offset in the embedded module graph before reading it **Resolver, module loading, plugins, paths** (25) - #32269 Bun.plugin: validate the namespace without a shared regex - #33183 bun:jsc: filter internal cells out of getProtectedObjects() - #34575 Don't register native functions as their own constructors - #36340 paths: size the thread-local join output buffers to MAX_PATH_BYTES on Windows - #37037 mock.module: reject async factory results that are not objects - #37065 bun:jsc: propagate JSONParse exceptions from samplingProfilerStackTraces - #37529 resolver: don't abort on a package.json sideEffects entry longer than the join buffer - #38179 node:module: throw instead of crashing when module._compile is set to a non-function - #38273 bun test: report a test file or preload the loader cannot resolve instead of exiting; keep the JUnit report valid U… *(crash fix only)* - #38732 paths: compute the common path of 9+ inputs with the same loop as fewer *(crash fix only)* - #39228 paths: strip C:\\ down to the drive root in without_trailing_slash_windows_path *(crash fix only)* - #39650 bun run --filter: stop panicking on workspace paths longer than the path buffer - #40186 resolver: stop deeply nested exports targets from overflowing the stack - #40258 resolver: publish Entry.abs_path through the per-entry mutex - #42183 node:module: reject a _resolveFilename override result that contains a null byte - #42401 node:module: accept any `this` in Module.prototype.require *(crash fix only)* - #42405 Bun.plugin: transpile a copy of typed array onLoad contents - #42414 node:module: end the Module._stat path at the first null byte - #42685 resolver: strip the trailing separator inside bust_dir_cache - #42735 Throw a RangeError instead of aborting when require.resolve paths or Worker preload outgrows its Vector - #43067 Report a path that does not fit a path buffer instead of aborting *(crash fix only)* - #44410 Fix a crash when code from a node:vm context reads require.cache or require.extensions - #44466 Trace the value an object or data module exports from its JSSourceCode - #45044 Bun.plugin: give onLoad's args.path its own bytes - #45117 cjs: do not call an `__esModule` getter during the annotation lookup **Dev server, `bun bake`, routers, `--watch` and `--hot`** (28) - #28793 Stop file watcher thread before Global.exit tears down memory *(crash fix only)* - #32143 bake: fix "Runtime file not found" panic in production builds of custom frameworks - #32443 watcher: don't free the Watcher in the spawn-to-start window *(crash fix only)* - #33232 bake: normalize the HTTP request-target before matching framework routes - #36812 bake: respond 500 and release both RequestContext refs when on_plugins_rejected / OOM drains a deferred framework r… - #37039 bake: report per-file print failures in the dev server instead of serving empty modules - #37276 hot_reloader: take entries_mutex for watcher-thread directory cache probes - #37444 bake: unregister Bake::SourceProvider from the source map table when it is destroyed - #39290 FileSystemRouter: match / against a root-level optional catch-all route *(crash fix only)* - #39291 FileSystemRouter: order dynamic routes by per-segment precedence like Next.js *(crash fix only)* - #39629 watch: report a failed watcher init as an error instead of a crash - #41185 bake: check for exceptions in the production build's module loader hooks and helpers - #41340 bake: skip the directory watch when the directory cannot be opened - #41617 Decide a directory watch event from the watchlist, not from the resolver's cached listing *(crash fix only)* - #42547 bake: re-arm the memory visualizer timer when it fires - #42733 dev server: make a client script request wait for the bundle in flight - #42828 bake: serve routes from a router root outside the project root instead of aborting or answering 404 - #42831 bake: resolve app.root and router roots through one checked join - #42836 bake: report route scan errors instead of aborting, and fail bun build --app on them *(crash fix only)* - #42840 dev server: map a router type's server entry point to the root route of that type - #42862 Bun.serve: return before a pending app.plugins setup() settles *(crash fix only)* - #42920 Do not create a mimalloc heap per FileSystemRouter, reload() or :nth-child(An-B) selector - #42934 dev server: register a client component without evaluating it - #43329 dev server: check the route bundle index of a client script URL before Index::init - #44249 fs.watch: read each directory and close it before descending - #44344 Windows: fix a watcher panic and lost events in a burst of file changes, and a --hot that stops watching a deleted… - #44744 dev server: answer a cached-file lookup only for a graph that bundled the file - #44746 dev server: keep an importer in its own graph when an import fails or is deleted **`Bun.serve`, sockets, HTTP, WebSocket, HTTP/2, QUIC, DNS** (28) - #42667 Reland "usockets(windows): keep a closed poll alive until the outer tick and libuv are done with it" (#39643) - #33015 fix(windows): segfault in uv__wake_all_loops after system resume *(crash fix only)* - #35761 node:quic: detach lsquic ctx pointers before the finalize-order sweep at worker VM teardown - #37082 Bun.serve: terminate FIFO/pipe file responses at EOF - #38024 dns: keep the c-ares uv_poll_t alive while its poll callback is on the stack (Windows) - #38636 serve: fix route use-after-free after reload() with tls.serverName *(crash fix only)* - #40888 server.fetch: copy a Headers argument instead of adopting the wrapper's pointer - #41337 Update lsquic to 4.9.4 and free unsent stateless resets on destroy *(crash fix only)* - #41384 usockets: hold a tick level for the whole of close_all - #41412 Windows: wait for close completions when closing a worker's uv loop - #41516 node:http2: handle an empty byte range in respondWithFile and respondWithFD - #41521 udp: report every binaryType from the getter, reject a dgram bind of the other family *(crash fix only)* - #42188 net: do not assert a two-character host in SocketAddress.parse - #42210 libuv(windows): keep a pipe's completed read counted until its read callback returns - #42334 fetch, Bun.serve: throw a RangeError for Headers that total 4 GiB or more *(crash fix only)* - #43738 usockets: close a socket whose resume the kernel refuses from the loop, not from the caller - #44338 node:http: response trailers travel with the end call of the response *(crash fix only)* - #44433 bake: make the parked-request list non-owning and look up the DevServer when a plugin load settles - #44533 node:quic: capture the handshake while the conn is alive, set the application at session creation - #44734 Bun.serve: answer HEAD for an S3-backed Blob body without an S3 stat - #44751 node:quic: close() waits only for opened streams, and lsquic sends no GOAWAY before HTTP/3 starts *(crash fix only)* - #44897 node:http2: throw instead of panic when the native setNextStreamID() misses its argument - #45076 node:http2: let close() and destroy() win over the refusal of a request - #45341 uws: AsyncSocket::write takes a size_t length, so res.end() sends a body of 2 GiB or more whole - #45522 node:http2: throw for an ALTSVC frame that is too long and for a pushPromise id that is not a stream id - #45676 node:quic: do not reset a stream lsquic has already finished - #45822 node:quic: name a stream in queued session events by a per-session key, not by its address - #45858 Bun.serve WebSocket: a message that does not fit in memory fails one connection, not the server *(crash fix only)* **Streams, Blob, S3, files, `node:fs`** (28) - #33845 io: propagate IoRequestLoop init failure instead of aborting *(crash fix only)* - #36365 prompt: drop debug_assert that rejects answers containing CR - #37090 Deliver FIFO bodies whose writer connects after the reader opens *(crash fix only)* - #38039 node:fs: stop fs.copyFile(src, "") from segfaulting on Windows - #38653 shell(cp): reject copying a directory into itself; walk cp trees without recursion - #39207 Convert scope-object receivers in the chaining functions and inspect.custom fallbacks - #39390 Blob deserialize: reject over-long paths, treat size >= MAX_SIZE as unknown, make slice() non-panicking - #39639 fetch: drop the upload and drain hop refs at VM teardown *(crash fix only)* - #40008 inspect hooks: copy user options with putDirectMayBeIndex *(crash fix only)* - #40462 Windows: FileSink.start({ path }) on a live writer: hand the writer a libuv fd and close the old source *(crash fix only)* - #41440 node:fs: pass the buffer to the read/readv/write/writev callback on error - #41584 Walk the timer pairing heap without recursion - #41608 native-readable: accept a stream with no native handle - #41710 JSSink write(): convert the chunk before resolving the native sink *(crash fix only)* - #42711 webstreams: bound the native recursion through a chain of tees or text streams - #43264 fetch: reject a file: URL whose path has an encoded NUL - #43709 s3: fix double free of a multipart part's bytes on worker terminate - #43950 streams: link readers and writers last, reject their promises as handled - #44036 PipeReader: label a chunk Eof only when the reader is at its end - #44181 streams: throw instead of aborting when a direct stream's text sink cannot take a string chunk - #44195 fs: validate POSIX directory records in one parser, report a malformed record as EIO *(crash fix only)* - #44269 streams: join the string chunks of a text consumer with one allocation - #44490 watch(windows): report a failed child spawn as an error instead of a panic *(crash fix only)* - #44954 process.stdout/stderr with no FileSink: write synchronously, reset after a failed write *(crash fix only)* - #45004 streams: leave a stream alone when a consumer fails to lock it - #45521 FileSink: throw ERR_ILLEGAL_CONSTRUCTOR from the constructor that script reaches by writer.constructor - #45738 s3: own the Blob store across the calls that run user JS - #45975 node:stream: do not touch the web controller after the web side is done **Node-API, V8 API, `bun:ffi`, `process.dlopen`** (15) - #36609 napi: implement uv_cwd on POSIX - #37989 bun:ffi: stop cc() from turning non-numeric pointer arguments into garbage pointers - #38057 bun:ffi: make cc() reject non-numeric i64/u64 arguments instead of passing garbage - #38425 bun:ffi: throw on an empty cc() source array instead of panicking - #39652 napi: implement uv_async_t, uv_queue_work and uv_default_loop on posix - #39805 Share one handle scope implementation between Node-API and the V8 API - #39892 napi: implement uv_idle_t, uv_prepare_t, uv_check_t and uv_timer_t on posix - #40144 bun:ffi: return undefined for a NULL napi_value from cc() and throw the scheduled napi exception - #40773 bun:ffi: add the full byteOffset in read.*, do not truncate it to int32 - #41704 napi: hand the thrown value to napi_get_and_clear_last_exception after napi_run_script - #42960 process.dlopen: run a V8 addon's init function after dlopen() returns - #43797 Fix debug assertion on an empty error message from a V8 addon or SQLite *(crash fix only)* - #43802 bun:ffi: throw a TypeError when a cc() symbol is called after its library's close() - #43940 napi: fail with ERR_BUFFER_TOO_LARGE instead of aborting above the ArrayBuffer limit *(crash fix only)* - #44921 bun:ffi: pad a short call to a cc() symbol with undefined **`node:vm`, workers, process, timers** (19) - #34623 node:vm: run DONT_CONTEXTIFY contexts directly against the real global - #32839 node:vm: reject invalid cachedData instead of crashing - #36921 error printer: clear the pending exception when formatting a non-Error uncaught value throws - #37270 error printer: one render per error, [Circular] under the key that closes the cycle - #38740 bun:test: give each VM its own fake clock *(crash fix only)* - #39864 Report a refused HTTP, bundle, IO or process waiter thread as an error instead of a crash *(crash fix only)* - #39992 process: deliver exceptions reported against a node:vm context to uncaughtException - #41654 node:vm: give each SourceTextModule request the import attributes of the declaration that created it *(crash fix only)* - #41739 Do not forward the inherited IPC channel to spawned scripts and tools - #41769 node:vm: stop compiling accepted cachedData, report each cachedData decode to the GC *(crash fix only)* - #42045 bun:test fake timers: never move the fake clock backwards - #42308 process.execve: throw instead of aborting for a string past the string limits - #42734 node:vm: report cachedData of 2 GiB or more as rejected instead of aborting - #42843 process.dlopen: reject a filename of PATH_MAX or more before dlopen() - #43500 process: accept SIGSTKFLT, SIGPOLL and SIGPWR, and emit every name of a signal number *(crash fix only)* - #44486 worker: stop the start sequence when a handler it calls stops the worker - #44771 timers: allocate ids from one 64-bit counter that never wraps - #44837 --hot: defer a reload during the preloads, and report a reload that cannot start - #44991 Fix a use-after-free in the VM ref-string intern for a string over the length limit **Shell, spawn, CLI, `bun test`, `bun install`** (31) - #30642 Fail fast at startup when simdutf has no usable implementation for this CPU - #34223 Fix four crashes: HTMLRewriter disturbed body, S3 locked-stream upload, ConnectionsList closed parser, shell brace… *(crash fix only)* - #34884 Guard the console and test-runner formatters against native stack overflow on deeply nested values *(crash fix only)* - #36584 process.chdir: publish an immutable cwd slice so no thread sees a torn cwd - #37135 bun test --parallel: hold the JSC API lock while draining the worker's final IPC backlog - #37527 shell(mv): report ENAMETOOLONG instead of panicking when a source name does not fit the path buffers - #37528 cli: stop aborting on absolute script paths longer than 1024 bytes on Windows - #38162 shell(cp): report ENAMETOOLONG instead of panicking on operands longer than the path buffers - #38205 shell(windows): report ENAMETOOLONG for operands that do not fit the path buffer - #39010 bun test: exit through the VM teardown path when --bail stops a run - #39104 bun test: report over-long coverage dir, JUnit outfile and bunfig root instead of panicking *(crash fix only)* - #39638 shell(cat): serve a second cat on the same stdin instead of hanging or panicking - #39641 usockets: report an out-of-descriptors event loop init as an error, not a crash *(crash fix only)* - #40181 shell: stop deeply nested if clauses from overflowing the parser stack - #40885 shell: throw instead of panicking when a ReadableStream is used as a redirect - #41155 ipc: send a queue item larger than 2 GiB in capped write requests - #42298 bun:test: print String objects with 16-bit storage correctly - #42577 bun:test: root the return values toHaveReturnedWith collects - #43606 shell(windows): report a failed pipe reader start through on_reader_error instead of leaking the subprocess *(crash fix only)* - #43838 node:cluster: read a worker's `ack` and `addressType` in the primary only when they are int32 - #44172 node:cluster: refuse a descriptor of the wrong kind in the primary *(crash fix only)* - #44185 node:cluster: one handle for each descriptor that workers name *(crash fix only)* - #44491 bun test: run every callback when native code leaves an exception pending *(crash fix only)* - #44694 shell mv: refuse to copy a directory into itself on the cross-device fallback - #44752 shell: take the command-substitution capture and drop its NUL bytes - #44981 shell: reject NUL bytes in .cwd() and .env() at the native setters - #45206 ini: reject a source of 2 GiB or more in Parser::parse instead of aborting on an int cast *(crash fix only)* - #45348 bun test: fix a segfault in .not.toThrow(Class) when Symbol.hasInstance accepts a thrown string, symbol or BigInt - #45649 shell: replace the output counters in mkdir, cp, ls and touch with the OutputTask queue - #45792 bun test: SIGKILL a spawnSync child that is still running 500 ms after the test's timeout *(crash fix only)* - #45910 create: own the remote-template response buffers instead of parking them in the CLI arena **Web APIs, Buffer, encoding, URL, crypto, zlib, SQLite, Redis and the rest** (96) - #29709 console: guard JSX/Proxy recursion in Bun.inspect (stack overflow SIGSEGV) - #30817 console.takeHeapSnapshot: clear prior snapshots before building - #30956 spawnSync: make signal-forwarding register/unregister safe for concurrent callers *(crash fix only)* - #31505 node:zlib: reject invalid brotli flush values at validation *(crash fix only)* - #31735 node:path: fix win32 drive-relative resolve on non-Windows hosts *(crash fix only)* - #32085 Fix crash when RedisClient onclose/onconnect is set to a non-callable - #32240 Fix BroadcastChannel custom inspect crash with numeric option keys - #33181 Reject interior null bytes in Bun.mmap, Glob.scan, and FileSystemRouter paths *(crash fix only)* - #33752 node:crypto: validate EC JWK private scalar matches public point in createPrivateKey - #34976 spyOn: install and restore through one writer that throws when the object refuses *(crash fix only)* - #35562 structuredClone: purify NaN in deserialized Date timestamp so getTime never returns a forged JSValue - #35618 napi(windows): load addons that import node.exe without win_delay_load_hook - #35757 Coerce later arguments before capturing input buffers in Bun.Transpiler and Bun.RedisClient - #37252 Report UTF-16 to UTF-8 encode counts through size_t so exactly 2^32 written bytes doesn't wrap to 0 - #37338 node:module: build require.cache without user-writable globals and propagate its exceptions *(crash fix only)* - #37340 redis: accept unsubscribe acks that arrive outside subscriber mode - #37370 Error.appendStackTrace: make appending an error's trace to itself a no-op - #37443 node:crypto: fix null deref when worker.terminate() lands during an EC JWK private key import - #37448 jsc: check for exceptions before using a stored constructEmptyArray result *(crash fix only)* - #38009 MessagePort: fix a heap-use-after-free in contextDestroyed(), release ref() when the last 'message' listener is rem… *(crash fix only)* - #38469 napi: settle or refuse async work queued during VM teardown instead of taking a ticket - #38708 Handle 16-bit module sources in the error preview, the new-position fix-up and the REPL *(crash fix only)* - #38821 process.env: make a failed env build throw instead of aborting (Windows 0xC0000409 on Bun.$ / Bun.sql / process.env… - #38871 process.env: coerce to string on every execution of an assignment, not just the first - #38877 cli: exit 128 + signo when bun cannot die from a re-raised signal (bun as container PID 1) - #38926 Clear the inherited signal mask at startup and exec children with an empty one *(crash fix only)* - #39382 Make a failed util.inspect load throw from custom inspect functions instead of aborting - #39481 Always create the error when a native error message exceeds the string length limit - #39651 performance: keep the user timing entry counts exact after clearMarks(name) and clearMeasures(name) - #39775 Turn seccomp SIGSYS traps into ENOSYS so the syscall fallbacks run on Android - #39968 process.dlopen: replay a non-context-aware V8 addon only while no other live VM owns it - #39975 watch: report a failed reload exec as an error instead of a panic *(crash fix only)* - #40346 Give Glob's native scan methods their own private names - #40554 node:crypto: copy password and salt for async pbkdf2 and scrypt - #40567 url: reject URL-encoded input over the WTF decode limit instead of aborting - #40577 url: throw a RangeError instead of aborting when URLSearchParams or FormData outgrows its Vector - #41073 Store array-index property names as indexed properties in native object builders - #41137 Write the sampling profiler report at exit from Bun, not JSC's atexit hook - #41365 webview: fail only the view when WebKit lacks initWithDirectory: - #41574 Decode a private copy of a JS buffer in the UTF-8 decoders *(crash fix only)* - #41652 console: read a BigInt depth option by value in console.dir - #41749 Startup: reopen fd 0-2 as /dev/null only when the fd is closed - #41819 Report an incoherent BUN_JSC_* option combination as a configuration error, not a crash *(crash fix only)* - #42158 webview: reject malformed Chrome replies instead of crashing - #42179 shell: clamp a `> ${buf}` redirect to the target buffer's live length - #42187 node:crypto: throw ERR_OUT_OF_RANGE for >2 GiB buffer arguments instead of aborting - #42191 URLPattern: throw instead of aborting when a pattern string passes the string limit - #42192 Copy WebAssembly.Memory bytes for native borrows that outlive the call *(crash fix only)* - #42198 Make Bun.$, Bun.sql, Bun.postgres and Bun.SQL custom value getters so reifying the Bun object passes exception chec… - #42203 node:fs: fs.read into a WebAssembly.Memory view writes into the block a grow freed - #42214 Headers: throw a RangeError instead of aborting when the set-cookie list cannot grow - #42218 Headers: throw instead of aborting when a value passes the string length limit - #42220 URLPattern: throw instead of aborting when the token list cannot grow - #42225 Throw ERR_STRING_TOO_LONG from Bun.wrapAnsi instead of aborting when the output passes the string length limit - #42226 Throw instead of aborting when a MIME string does not fit in a string *(crash fix only)* - #42237 Bun.Cookie: throw instead of aborting when the Set-Cookie string passes the string length limit - #42249 Copy a shared input before libdeflate compresses it in Bun.gzipSync and Bun.deflateSync - #42253 bun test: walk nested describe scopes without native recursion - #42259 Throw instead of aborting when a domainToASCII host passes the string length limit - #42310 Parse a private copy of a shared or resizable buffer in Bun.Transpiler, Bun.markdown, Bun.YAML and Bun.TOML *(crash fix only)* - #42312 YAML, JSON5, XML stringify: throw instead of aborting when the output passes the string length limit - #42318 Bound libdeflate's emit path so a racing input cannot overrun the output - #42338 inspector: check the type of process.argv in getModuleGraph - #42364 node:perf_hooks: do not truncate the monitorEventLoopDelay resolution to int32 - #42412 transpiler cache: reject an entry with no sourcemap section - #42479 worker_threads: do not abort when markAsUntransferable/markAsUncloneable gets a WebAssembly GC reference - #42517 EventTarget: skip a listener object that has no realm - #42518 fs.Stats: make the date accessors define the property like Object.defineProperty *(crash fix only)* - #42575 Stop natives from writing onto a foreign `this` with putDirect: process.ppid, require.cache, StringDecoder, the nat… *(crash fix only)* - #42631 JSStringView: pin the cell that owns the borrowed characters - #42660 bun_core: read /dev/urandom when getrandom(2) answers ENOSYS or EPERM - #42780 node:crypto: treat a name too long to convert to UTF-8 as unknown instead of aborting - #42782 node:crypto: throw ERR_OUT_OF_RANGE for a passphrase larger than INT_MAX bytes - #42856 url: do not abort when a host is too long for the IDNA conversion buffers - #42868 sqlite, console, process: do not abort on a string too long to convert to UTF-8 *(crash fix only)* - #42941 Bun.sliceAnsi: throw instead of aborting when the result passes the string length limit - #43058 Bun.serve: fix crash and cross-request 500 when inspecting a non-Response return value throws - #43904 JSC bindings: build property keys from a BunString through Bun::toIdentifier - #44124 Bun.Image: decode WebP into a Bun-owned canvas and read ICCP without the demuxer *(crash fix only)* - #44190 Convert scope-object receivers before Buffer read*/write* and vm.Script describe them - #44211 Stop getsockname(out), useFakeTimers() and the stream source pull() from writing onto a caller's object with putDirect - #44295 bun test --coverage: append a final newline to a text that lacks one *(crash fix only)* - #44360 rust-argon2: return OutOfMemory instead of aborting when the memory cost cannot be allocated - #44421 node:zlib: free zstd's workers before the dictionary they read - #44521 util.parseArgs: pick the default args start from a per-VM eval flag, as Node v26 does *(crash fix only)* - #44740 structured clone: tolerate a zero-sized shared WebAssembly.Memory in computeMemoryCost() - #44759 HTMLRewriter: park a suspended handler's token before the output flush - #44907 Builtins section format 2: an engine stamp says which buns compile its modules - #45188 Reject an oversized WebCrypto cipher output instead of aborting - #45354 Throw for a `file:` URL whose path is not UTF-8 on Linux and macOS, through one `fileSystemPath()` accessor *(crash fix only)* - #45608 ipc: refuse an over-long message before the receive buffer stores it - #45624 webcrypto: write the key type into the X25519 structured-clone record - #45625 node:sqlite: refuse session.close() and Symbol.dispose inside a SQLite callback - #45653 glob: a group with `?` or a class matches when an alternative takes 64 bytes or more - #45820 Bun.file, S3Client.file and Bun.write no longer keep a buffer path alive forever - #45832 `bun check`: fix a panic on `export *` without a module specifier, and a false error for one in parentheses ### Already fixed on `main`, or duplicates of a pull request above Already fixed: #27323 #30401 #31011 #31206 #31566 #31626 #31695 #31702 #31945 #32773 #34154 #34697 #34744 #34964 #35655 #35816 #36020 #36181 #36296 #36342 #36581 #36602 #36807 #36818 #36857 #37172 #37235 #37239 #37267 #37420 #37731 #37914 #38113 #38119 #38509 #38514 #38540 #38975 #39410 #40749 #41163 #41171 #42108 #43085 #43230 Duplicates: #45654 #29986 #33378 #36895 #37070 #37639 #38014 #39021 #41266 #42250 #42951 #43238 #44259 #45335 #45565 #45726 #45965 Fixes #5019 Fixes #6106 Fixes #10690 Fixes #10886 Fixes #13566 Fixes #14745 Fixes #15551 Fixes #20454 Fixes #21310 Fixes #29145 Fixes #30454 Fixes #30613 Fixes #30766 Fixes #32103 Fixes #32142 Fixes #32183 Fixes #32212 Fixes #39060 Fixes #42296 Fixes #42931 Fixes #43671 Fixes #44201 Fixes #44735 Fixes #44783 Fixes #45198 Fixes #45327 Fixes #45491 Fixes #45721 --------- Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
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This is Claude (an AI assistant) commenting on Jarred's behalf. While putting #46021 together we checked this against |
Fixes a use-after-free behind a cluster of Sentry crash reports (BUN-3EA0, BUN-3EA2, BUN-3EA5, BUN-3EAK): four distinct memory-death signatures (segfaults in
deref_mut,EString::init,baby_vec::drop, andRawVecInner::try_allocate_in), all withgenerate_react_refresh_import_hmron the stack — i.e. scattered crashes inside the dev server's parser codegen.Root cause
Tearing down a VM or DevServer while its async bundle still has ParseTasks running on the shared
WorkPoolfrees memory those tasks dereference:WebWorker::shutdowndeallocates theVirtualMachinebox. The bundle'sAnyEventLoop::Jshandle points atvm.event_loop, a value field of that box, so a straggler ParseTask's result enqueue reads freed memory:Drop for DevServerletcurrent_bundle's automatic field drop free theBundleV2, the bundle mi-heap (which arena-owns theParseTasks themselves), and theAstAllocState. The Zig implementation deliberately leaked this state (DevServer.zigdeinit,.current_bundlearm: "impossible to de-initialize this state correctly"); the Rust port kept only the debug assert and freed anyway.In release builds the stray reads/writes land in recycled mimalloc blocks and surface later as unrelated-looking segfaults in allocation-heavy code — the react-refresh import codegen is the biggest allocation burst at the end of every dev-server JSX parse, which is why all four crash signatures cluster in that frame.
These straggler tasks can be neither cancelled (no cancellation mechanism exists) nor waited for (the event loop that would drain their completions has stopped, so the completion that ends the bundle can never run). The only sound teardown is the one Zig chose: leak.
Fix
VirtualMachine::pending_async_bundles: new same-thread counter, incremented byDevServer::start_async_bundle, decremented whenfinalize_bundleclearscurrent_bundle.WebWorker::shutdown: when the counter is nonzero, leak the VM (and the env loader/map, uws loop, and worker arena that the stragglers also reach) instead of freeing them, and sethas_terminatedso straggler enqueues bail out.Drop for DevServer: leakcurrent_bundle(Zig parity) instead of dropping it.EventLoop::enqueue_task_concurrent{,_batch}: a terminated VM never drains its queue again, so the enqueue is now a no-op (previously a debug-only panic, which turned a legitimate terminate-mid-bundle into an abort).Reproduction / verification
worker.terminate()while the worker's dev server (Bun.servewith an HTML route) is mid-bundle reproduces the UAF deterministically under ASAN. The new regression test intest/bake/deinitialization.test.tssweeps the terminate timing against a bundle of 24 JSX components (hooks + a bundler macro, mirroring the react-refresh transform the production crashes went through):heap-use-after-freeaboveAlso verified:
test/bake/dev/react-spa.test.ts,test/bake/dev/hot.test.ts,test/bake/dev/stress.test.ts,test/regression/issue/25716.test.ts(Bun.build reactFastRefresh), and a 30-revision dev-server rebuild stress loop — all clean on the fixed build. The test isskipIf(!isASAN)since release builds corrupt silently.