runtime: fix Stacked Borrows violation in LocalOwnedTasks
#5099
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## Motivation It turns out that `LocalSet` has...never actually passed Miri. This is because all of the tests for `LocalSet` are defined as integration tests in `tokio/tests/task_local_set.rs`, rather than lib tests in `tokio/src`, and we never run Miri for integration tests. PR #5095 added a new test reproducing an unrelated bug in `LocalSet`, which had to be implemented as a lib test, as it must make internal assertions about the state of the `LocalSet` that cannot be tested with just the public API. This test failed under Miri, and it turns out that the reason for this is unrelated to the change in #5095 --- `LocalSet` uses the `LocalOwnedTasks` type, which turns out to contain a stacked borrows violation due to converting an `&Header` into an `NonNull<Header>` when removing a task from the `LocalOwnedTasks` list. ## Solution Fortunately, this was actually quite easy to fix. The non-`Local` version of `OwnedTasks` already uses `Task::header_ptr()` to get a `NonNull<Header>` in its version of `remove`, which avoids this issue. Therefore, the fix was as simple as updating `LocalOwnedTasks` to do the same. I've also added a very simple lib test in `src/task/local_set.rs` that just creates a `LocalSet` and spawns a single task on it under a current-thread runtime. This test fails under Miri without the fix in this PR: https://github.com/tokio-rs/tokio/actions/runs/3237072694/jobs/5303682530 We should probably keep the test so that we're always testing at least the most trivial `LocalSet` usage under Miri...
hawkw
changed the title
LocalOwnedTasks
Noah-Kennedy
approved these changes
Oct 12, 2022
crapStone
pushed a commit
to Calciumdibromid/CaBr2
that referenced
this pull request
Nov 22, 2022
This PR contains the following updates: | Package | Type | Update | Change | |---|---|---|---| | [tokio](https://tokio.rs) ([source](https://github.com/tokio-rs/tokio)) | dependencies | minor | `1.21.2` -> `1.22.0` | | [tokio](https://tokio.rs) ([source](https://github.com/tokio-rs/tokio)) | dev-dependencies | minor | `1.21.2` -> `1.22.0` | --- ### Release Notes <details> <summary>tokio-rs/tokio</summary> ### [`v1.22.0`](https://github.com/tokio-rs/tokio/releases/tag/tokio-1.22.0): Tokio v1.22.0 [Compare Source](tokio-rs/tokio@tokio-1.21.2...tokio-1.22.0) ##### Added - runtime: add `Handle::runtime_flavor` ([#​5138]) - sync: add `Mutex::blocking_lock_owned` ([#​5130]) - sync: add `Semaphore::MAX_PERMITS` ([#​5144]) - sync: add `merge()` to semaphore permits ([#​4948]) - sync: add `mpsc::WeakUnboundedSender` ([#​5189]) ##### Added (unstable) - process: add `Command::process_group` ([#​5114]) - runtime: export metrics about the blocking thread pool ([#​5161]) - task: add `task::id()` and `task::try_id()` ([#​5171]) ##### Fixed - macros: don't take ownership of futures in macros ([#​5087]) - runtime: fix Stacked Borrows violation in `LocalOwnedTasks` ([#​5099]) - runtime: mitigate ABA with 32-bit queue indices when possible ([#​5042]) - task: wake local tasks to the local queue when woken by the same thread ([#​5095]) - time: panic in release mode when `mark_pending` called illegally ([#​5093]) - runtime: fix typo in expect message ([#​5169]) - runtime: fix `unsync_load` on atomic types ([#​5175]) - task: elaborate safety comments in task deallocation ([#​5172]) - runtime: fix `LocalSet` drop in thread local ([#​5179]) - net: remove libc type leakage in a public API ([#​5191]) - runtime: update the alignment of `CachePadded` ([#​5106]) ##### Changed - io: make `tokio::io::copy` continue filling the buffer when writer stalls ([#​5066]) - runtime: remove `coop::budget` from `LocalSet::run_until` ([#​5155]) - sync: make `Notify` panic safe ([#​5154]) ##### Documented - io: fix doc for `write_i8` to use signed integers ([#​5040]) - net: fix doc typos for TCP and UDP `set_tos` methods ([#​5073]) - net: fix function name in `UdpSocket::recv` documentation ([#​5150]) - sync: typo in `TryLockError` for `RwLock::try_write` ([#​5160]) - task: document that spawned tasks execute immediately ([#​5117]) - time: document return type of `timeout` ([#​5118]) - time: document that `timeout` checks only before poll ([#​5126]) - sync: specify return type of `oneshot::Receiver` in docs ([#​5198]) ##### Internal changes - runtime: use const `Mutex::new` for globals ([#​5061]) - runtime: remove `Option` around `mio::Events` in io driver ([#​5078]) - runtime: remove a conditional compilation clause ([#​5104]) - runtime: remove a reference to internal time handle ([#​5107]) - runtime: misc time driver cleanup ([#​5120]) - runtime: move signal driver to runtime module ([#​5121]) - runtime: signal driver now uses I/O driver directly ([#​5125]) - runtime: start decoupling I/O driver and I/O handle ([#​5127]) - runtime: switch `io::handle` refs with scheduler:Handle ([#​5128]) - runtime: remove Arc from I/O driver ([#​5134]) - runtime: use signal driver handle via `scheduler::Handle` ([#​5135]) - runtime: move internal clock fns out of context ([#​5139]) - runtime: remove `runtime::context` module ([#​5140]) - runtime: keep driver cfgs in `driver.rs` ([#​5141]) - runtime: add `runtime::context` to unify thread-locals ([#​5143]) - runtime: rename some confusing internal variables/fns ([#​5151]) - runtime: move `coop` mod into `runtime` ([#​5152]) - runtime: move budget state to context thread-local ([#​5157]) - runtime: move park logic into runtime module ([#​5158]) - runtime: move `Runtime` into its own file ([#​5159]) - runtime: unify entering a runtime with `Handle::enter` ([#​5163]) - runtime: remove handle reference from each scheduler ([#​5166]) - runtime: move `enter` into `context` ([#​5167]) - runtime: combine context and entered thread-locals ([#​5168]) - runtime: fix accidental unsetting of current handle ([#​5178]) - runtime: move `CoreStage` methods to `Core` ([#​5182]) - sync: name mpsc semaphore types ([#​5146]) [#​4948]: tokio-rs/tokio#4948 [#​5040]: tokio-rs/tokio#5040 [#​5042]: tokio-rs/tokio#5042 [#​5061]: tokio-rs/tokio#5061 [#​5066]: tokio-rs/tokio#5066 [#​5073]: tokio-rs/tokio#5073 [#​5078]: tokio-rs/tokio#5078 [#​5087]: tokio-rs/tokio#5087 [#​5093]: tokio-rs/tokio#5093 [#​5095]: tokio-rs/tokio#5095 [#​5099]: tokio-rs/tokio#5099 [#​5104]: tokio-rs/tokio#5104 [#​5106]: tokio-rs/tokio#5106 [#​5107]: tokio-rs/tokio#5107 [#​5114]: tokio-rs/tokio#5114 [#​5117]: tokio-rs/tokio#5117 [#​5118]: tokio-rs/tokio#5118 [#​5120]: tokio-rs/tokio#5120 [#​5121]: tokio-rs/tokio#5121 [#​5125]: tokio-rs/tokio#5125 [#​5126]: tokio-rs/tokio#5126 [#​5127]: tokio-rs/tokio#5127 [#​5128]: tokio-rs/tokio#5128 [#​5130]: tokio-rs/tokio#5130 [#​5134]: tokio-rs/tokio#5134 [#​5135]: tokio-rs/tokio#5135 [#​5138]: tokio-rs/tokio#5138 [#​5138]: tokio-rs/tokio#5138 [#​5139]: tokio-rs/tokio#5139 [#​5140]: tokio-rs/tokio#5140 [#​5141]: tokio-rs/tokio#5141 [#​5143]: tokio-rs/tokio#5143 [#​5144]: tokio-rs/tokio#5144 [#​5144]: tokio-rs/tokio#5144 [#​5146]: tokio-rs/tokio#5146 [#​5150]: tokio-rs/tokio#5150 [#​5151]: tokio-rs/tokio#5151 [#​5152]: tokio-rs/tokio#5152 [#​5154]: tokio-rs/tokio#5154 [#​5155]: tokio-rs/tokio#5155 [#​5157]: tokio-rs/tokio#5157 [#​5158]: tokio-rs/tokio#5158 [#​5159]: tokio-rs/tokio#5159 [#​5160]: tokio-rs/tokio#5160 [#​5161]: tokio-rs/tokio#5161 [#​5163]: tokio-rs/tokio#5163 [#​5166]: tokio-rs/tokio#5166 [#​5167]: tokio-rs/tokio#5167 [#​5168]: tokio-rs/tokio#5168 [#​5169]: tokio-rs/tokio#5169 [#​5171]: tokio-rs/tokio#5171 [#​5172]: tokio-rs/tokio#5172 [#​5175]: tokio-rs/tokio#5175 [#​5178]: tokio-rs/tokio#5178 [#​5179]: tokio-rs/tokio#5179 [#​5182]: tokio-rs/tokio#5182 [#​5189]: tokio-rs/tokio#5189 [#​5191]: tokio-rs/tokio#5191 [#​5198]: tokio-rs/tokio#5198 </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about these updates again. --- - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate). <!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzNC4yNy4xIiwidXBkYXRlZEluVmVyIjoiMzQuMjkuMiJ9--> Co-authored-by: cabr2-bot <cabr2.help@gmail.com> Reviewed-on: https://codeberg.org/Calciumdibromid/CaBr2/pulls/1651 Reviewed-by: crapStone <crapstone@noreply.codeberg.org> Co-authored-by: Calciumdibromid Bot <cabr2_bot@noreply.codeberg.org> Co-committed-by: Calciumdibromid Bot <cabr2_bot@noreply.codeberg.org>
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Motivation
It turns out that
LocalSethas...never actually passed Miri. This isbecause all of the tests for
LocalSetare defined as integration testsin
tokio/tests/task_local_set.rs, rather than lib tests intokio/src, and we never run Miri for integration tests.PR #5095 added a new test reproducing an unrelated bug in
LocalSet,which had to be implemented as a lib test, as it must make internal
assertions about the state of the
LocalSetthat cannot be tested withjust the public API. This test failed under Miri, and it turns out that
the reason for this is unrelated to the change in #5095 ---
LocalSetuses the
LocalOwnedTaskstype, which turns out to contain a stackedborrows violation due to converting an
&Headerinto anNonNull<Header>when removing a task from theLocalOwnedTaskslist.Solution
Fortunately, this was actually quite easy to fix. The non-
Localversion of
OwnedTasksalready usesTask::header_ptr()to get aNonNull<Header>in its version ofremove, which avoids this issue.Therefore, the fix was as simple as updating
LocalOwnedTasksto do thesame.
I've also added a very simple lib test in
src/task/local_set.rsthatjust creates a
LocalSetand spawns a single task on it under acurrent-thread runtime. This test fails under Miri without the fix in
this PR: https://github.com/tokio-rs/tokio/actions/runs/3237072694/jobs/5303682530
We should probably keep the test so that we're always testing at least
the most trivial
LocalSetusage under Miri...