Allow spawning threads after TLS destruction #138702

m-ou-se · 2025-03-19T11:51:10Z

rustbot · 2025-03-19T11:51:16Z

rustbot has assigned @Mark-Simulacrum.
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Mark-Simulacrum

r=me with docs added (or maybe comment on the unstable tracking issue)

Mark-Simulacrum · 2025-03-23T16:35:46Z

library/std/src/thread/spawnhook.rs

+        ChildSpawnHooks { hooks, to_run }
+    } else {
+        // TLS has been destroyed. Skip running the hooks.
+        // See https://github.com/rust-lang/rust/issues/138696


Should we document this in add_spawn_hook ("for every newly thread spawned"), maybe as a footnote or something like that?

This comment seems unresolved? I agree that it'd be good to document this.

I responded to it below:

Added it to the tracking issue for now.

We might want to investigate exactly when this can and cannot happen before stabilizing (and documenting).

m-ou-se · 2025-03-26T08:59:05Z

Added it to the tracking issue for now.

We might want to investigate exactly when this can and cannot happen before stabilizing (and documenting).

@bors r=Mark-Simulacrum

bors · 2025-03-26T08:59:08Z

📌 Commit 5912dad has been approved by Mark-Simulacrum

It is now in the queue for this repository.

…mulacrum Allow spawning threads after TLS destruction Fixes rust-lang#138696

Rollup of 9 pull requests Successful merges: - rust-lang#130883 (Add environment variable query) - rust-lang#138672 (Avoiding calling queries when collecting active queries) - rust-lang#138702 (Allow spawning threads after TLS destruction) - rust-lang#138935 (Update wg-prio triagebot config) - rust-lang#138946 (Un-bury chapters from the chapter list in rustc book) - rust-lang#138964 (Implement lint against using Interner and InferCtxtLike in random compiler crates) - rust-lang#138977 (Don't deaggregate InvocationParent just to reaggregate it again) - rust-lang#138980 (Collect items referenced from var_debug_info) - rust-lang#138985 (Use the correct binder scope for elided lifetimes in assoc consts) r? `@ghost` `@rustbot` modify labels: rollup

Zalathar · 2025-03-27T04:53:18Z

Looks like this failed in rollup: #138994 (comment)

@bors r-

Zalathar · 2025-03-27T04:55:50Z

This probably just needs a //@ needs-threads in the test to skip inappropriate targets.

TaKO8Ki · 2025-03-27T05:09:42Z

Thanks. It failed with the following error message. #138994

Error

``` 2025-03-26T21:40:40.3315646Z failures: 2025-03-26T21:40:40.3315853Z 2025-03-26T21:40:40.3316147Z ---- [ui] tests/ui/thread-local/spawn-hook-atexit.rs stdout ---- 2025-03-26T21:40:40.3316528Z 2025-03-26T21:40:40.3325429Z error: test run failed! 2025-03-26T21:40:40.3325770Z status: exit status: 134 2025-03-26T21:40:40.3327164Z command: cd "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/thread-local/spawn-hook-atexit" && RUSTC="/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" RUST_TEST_THREADS="4" "/wasmtime-v19.0.0-x86_64-linux/wasmtime" "run" "-C" "cache=n" "--dir" "." "--env" "RUSTC_BOOTSTRAP" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/thread-local/spawn-hook-atexit/a.wasm" 2025-03-26T21:40:40.3328475Z stdout: none 2025-03-26T21:40:40.3328724Z --- stderr ------------------------------- 2025-03-26T21:40:40.3329095Z 2025-03-26T21:40:40.3329330Z thread 'main' panicked at /rustc/FAKE_PREFIX/library/std/src/thread/mod.rs:729:29: 2025-03-26T21:40:40.3329941Z failed to spawn thread: Error { kind: Unsupported, message: "operation not supported on this platform" } 2025-03-26T21:40:40.3330518Z note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace 2025-03-26T21:40:40.3331181Z Error: failed to run main module `/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/thread-local/spawn-hook-atexit/a.wasm` 2025-03-26T21:40:40.3331635Z 2025-03-26T21:40:40.3331726Z Caused by: 2025-03-26T21:40:40.3331945Z 0: failed to invoke command default 2025-03-26T21:40:40.3332513Z 1: error while executing at wasm backtrace: 2025-03-26T21:40:40.3333117Z 0: 0x731d - a.wasm!__rustc[e71bbdf1327cd442]::__rust_start_panic 2025-03-26T21:40:40.3333847Z 1: 0x711a - a.wasm!__rustc[e71bbdf1327cd442]::rust_panic 2025-03-26T21:40:40.3334874Z 2: 0x70ed - a.wasm!std::panicking::rust_panic_with_hook::hf7253cc1326481e4 2025-03-26T21:40:40.3335606Z 3: 0x618f - a.wasm!std::panicking::begin_panic_handler::{{closure}}::he12880ca3e35ef7a 2025-03-26T21:40:40.3336306Z 4: 0x60fb - a.wasm!std::sys::backtrace::__rust_end_short_backtrace::h5892030c5e958e1f 2025-03-26T21:40:40.3336770Z 5: 0x6a80 - a.wasm!__rustc[e71bbdf1327cd442]::rust_begin_unwind 2025-03-26T21:40:40.3337185Z 6: 0xb81b - a.wasm!core::panicking::panic_fmt::hfecdcbf9788721e5 2025-03-26T21:40:40.3337691Z 7: 0xd3a8 - a.wasm!core::result::unwrap_failed::h0cf8ff721cbe3fe3 2025-03-26T21:40:40.3338103Z 8: 0xa88 - a.wasm!std::thread::spawn::h6b69bdde073e2268 2025-03-26T21:40:40.3338488Z 9: 0x1802 - a.wasm!spawn_hook_atexit::main::h872f7eff79614d37 2025-03-26T21:40:40.3338951Z 10: 0x5c6 - a.wasm!std::sys::backtrace::__rust_begin_short_backtrace::h0654a70c6c569708 2025-03-26T21:40:40.3339424Z 11: 0x5b9 - a.wasm!std::rt::lang_start::{{closure}}::h53d8d7c9849aa50e 2025-03-26T21:40:40.3339848Z 12: 0x37bb - a.wasm!std::rt::lang_start_internal::h824b1b60e0c6fb40 2025-03-26T21:40:40.3340199Z 13: 0x183b - a.wasm!__main_void 2025-03-26T21:40:40.3340566Z 14: 0x325 - a.wasm!_start 2025-03-26T21:40:40.3341079Z 2: wasm trap: wasm `unreachable` instruction executed 2025-03-26T21:40:40.3341648Z ------------------------------------------ 2025-03-26T21:40:40.3341982Z ```

m-ou-se · 2025-03-27T07:56:19Z

@bors r=Mark-Simulacrum

bors · 2025-03-27T07:56:22Z

📌 Commit 3237b50 has been approved by Mark-Simulacrum

It is now in the queue for this repository.

…lacrum Allow spawning threads after TLS destruction Fixes rust-lang#138696

bors · 2025-03-27T11:02:24Z

⌛ Testing commit 3237b50 with merge 46fc17b...

bors · 2025-03-27T12:43:58Z

💔 Test failed - checks-actions

m-ou-se · 2025-03-27T13:11:29Z

@bors r=Mark-Simulacrum

bors · 2025-03-27T13:11:31Z

📌 Commit 6c2161a has been approved by Mark-Simulacrum

It is now in the queue for this repository.

bors · 2025-03-27T21:47:01Z

⌛ Testing commit 6c2161a with merge 7586a9f...

bors · 2025-03-28T00:57:00Z

☀️ Test successful - checks-actions
Approved by: Mark-Simulacrum
Pushing 7586a9f to master...

github-actions · 2025-03-28T00:59:17Z

What is this?

This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing 3f55023 (parent) -> 7586a9f (this PR)

Test differences

Show 3 test diffs

Stage 1

[ui] tests/ui/thread-local/spawn-hook-atexit.rs: [missing] -> pass (J1)

Stage 2

[ui] tests/ui/thread-local/spawn-hook-atexit.rs: [missing] -> ignore (only executed when the target family is unix) (J0)
[ui] tests/ui/thread-local/spawn-hook-atexit.rs: [missing] -> pass (J2)

Job group index

J0: i686-msvc-1, x86_64-mingw-1, x86_64-msvc-1
J1: x86_64-gnu-llvm-18-3, x86_64-gnu-llvm-19-3
J2: aarch64-apple, aarch64-gnu, arm-android, armhf-gnu, dist-i586-gnu-i586-i686-musl, i686-gnu-1, i686-gnu-nopt-1, test-various, x86_64-apple-2, x86_64-gnu, x86_64-gnu-llvm-18-1, x86_64-gnu-llvm-18-2, x86_64-gnu-llvm-19-1, x86_64-gnu-llvm-19-2, x86_64-gnu-nopt, x86_64-gnu-stable

Job duration changes

x86_64-apple-2: 5649.4s -> 6510.9s (15.2%)
dist-x86_64-apple: 8300.6s -> 9342.2s (12.5%)
dist-x86_64-linux-alt: 6792.2s -> 7332.8s (8.0%)
x86_64-apple-1: 7175.5s -> 7733.7s (7.8%)
i686-mingw-3: 7776.0s -> 8367.0s (7.6%)
dist-various-2: 3362.6s -> 3586.2s (6.7%)
dist-x86_64-musl: 7891.9s -> 8164.5s (3.5%)
dist-armv7-linux: 5290.0s -> 5451.4s (3.1%)
dist-x86_64-netbsd: 5200.3s -> 5355.1s (3.0%)
dist-x86_64-linux: 5437.7s -> 5598.0s (2.9%)

How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

rust-timer · 2025-03-28T02:18:00Z

Finished benchmarking commit (7586a9f): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

This benchmark run did not return any relevant results for this metric.

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 777.846s -> 778.708s (0.11%)
Artifact size: 365.94 MiB -> 365.91 MiB (-0.01%)

…lacrum Allow spawning threads after TLS destruction Fixes rust-lang#138696

m-ou-se added 2 commits March 19, 2025 12:49

Allow spawning threads after TLS destruction.

f23e76e

Add test.

5912dad

m-ou-se added the T-libs Relevant to the library team, which will review and decide on the PR/issue. label Mar 19, 2025

rustbot assigned Mark-Simulacrum Mar 19, 2025

rustbot added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Mar 19, 2025

m-ou-se mentioned this pull request Mar 19, 2025

std::thread::spawn: thread-local storage panics #138696

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Mark-Simulacrum reviewed Mar 23, 2025

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m-ou-se mentioned this pull request Mar 26, 2025

Tracking Issue for thread spawn hooks #132951

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bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 26, 2025

TaKO8Ki added a commit to TaKO8Ki/rust that referenced this pull request Mar 26, 2025

Rollup merge of rust-lang#138702 - m-ou-se:spawn-in-atexit, r=Mark-Si…

f7d6f30

…mulacrum Allow spawning threads after TLS destruction Fixes rust-lang#138696

TaKO8Ki mentioned this pull request Mar 26, 2025

Rollup of 9 pull requests #138994

Closed

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Add needs-threads to test.

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…lacrum Allow spawning threads after TLS destruction Fixes rust-lang#138696

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Mark test as only-unix.

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Auto merge of rust-lang#138702 - m-ou-se:spawn-in-atexit, r=Mark-Simu…

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…lacrum Allow spawning threads after TLS destruction Fixes rust-lang#138696

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