Merge branch 'tokio-1.38.x' into tokio-1.43.x

.cirrus.yml

@@ -1,7 +1,7 @@
 only_if: $CIRRUS_TAG == '' && ($CIRRUS_PR != '' || $CIRRUS_BRANCH == 'master' || $CIRRUS_BRANCH =~ 'tokio-.*')
 auto_cancellation: $CIRRUS_BRANCH != 'master' && $CIRRUS_BRANCH !=~ 'tokio-.*'
 freebsd_instance:
-  image_family: freebsd-14-1
+  image_family: freebsd-14-2
 env:
   RUST_STABLE: stable
   RUST_NIGHTLY: nightly-2024-05-05

.github/workflows/ci.yml

@@ -475,10 +475,18 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - name: Check semver
+      - name: Check `tokio` semver
         uses: obi1kenobi/cargo-semver-checks-action@v2
         with:
           rust-toolchain: ${{ env.rust_stable }}
+          package: tokio
+          release-type: minor
+      - name: Check semver for rest of the workspace
+        if: ${{ !startsWith(github.event.pull_request.base.ref, 'tokio-1.') }}
+        uses: obi1kenobi/cargo-semver-checks-action@v2
+        with:
+          rust-toolchain: ${{ env.rust_stable }}
+          exclude: tokio
           release-type: minor
 
   cross-check:
@@ -710,7 +718,14 @@ jobs:
           toolchain: ${{ env.rust_min }}
       - uses: Swatinem/rust-cache@v2
       - name: "check --workspace --all-features"
-        run: cargo check --workspace --all-features
+        run: |
+          if [[ "${{ github.event.pull_request.base.ref }}" =~ ^tokio-1\..* ]]; then
+            # Only check `tokio` crate as the PR is backporting to an earlier tokio release.
+            cargo check -p tokio --all-features
+          else
+            # Check all crates in the workspace
+            cargo check --workspace --all-features
+          fi
         env:
           RUSTFLAGS: "" # remove -Dwarnings
 
@@ -1006,10 +1021,10 @@ jobs:
           targets: ${{ matrix.target }}
 
       # Install dependencies
-      - name: Install cargo-hack, wasmtime, and cargo-wasi
+      - name: Install cargo-hack, wasmtime
         uses: taiki-e/install-action@v2
         with:
-          tool: cargo-hack,wasmtime,cargo-wasi
+          tool: cargo-hack,wasmtime
 
       - uses: Swatinem/rust-cache@v2
       - name: WASI test tokio full
@@ -1035,9 +1050,12 @@ jobs:
 
       - name: test tests-integration --features wasi-rt
         # TODO: this should become: `cargo hack wasi test --each-feature`
-        run: cargo wasi test --test rt_yield --features wasi-rt
+        run: cargo test --target ${{ matrix.target }} --test rt_yield --features wasi-rt
         if: matrix.target == 'wasm32-wasip1'
         working-directory: tests-integration
+        env:
+          CARGO_TARGET_WASM32_WASIP1_RUNNER: "wasmtime run --"
+          RUSTFLAGS: -Dwarnings -C target-feature=+atomics,+bulk-memory -C link-args=--max-memory=67108864
 
       - name: test tests-integration --features wasi-threads-rt
         run: cargo test --target ${{ matrix.target }} --features wasi-threads-rt

Cargo.toml

@@ -17,3 +17,16 @@ members = [
 
 [workspace.metadata.spellcheck]
 config = "spellcheck.toml"
+
+[workspace.lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = [
+  'cfg(fuzzing)',
+  'cfg(loom)',
+  'cfg(mio_unsupported_force_poll_poll)',
+  'cfg(tokio_allow_from_blocking_fd)',
+  'cfg(tokio_internal_mt_counters)',
+  'cfg(tokio_no_parking_lot)',
+  'cfg(tokio_no_tuning_tests)',
+  'cfg(tokio_taskdump)',
+  'cfg(tokio_unstable)',
+] }

examples/Cargo.toml

@@ -95,3 +95,6 @@ path = "named-pipe-multi-client.rs"
 [[example]]
 name = "dump"
 path = "dump.rs"
+
+[lints]
+workspace = true

tokio/CHANGELOG.md

@@ -303,6 +303,20 @@ Yanked. Please use 1.39.1 instead.
 [#6709]: https://github.com/tokio-rs/tokio/pull/6709
 [#6710]: https://github.com/tokio-rs/tokio/pull/6710
 
+# 1.38.2 (April 2nd, 2025)
+
+This release fixes a soundness issue in the broadcast channel. The channel
+accepts values that are `Send` but `!Sync`. Previously, the channel called
+`clone()` on these values without synchronizing. This release fixes the channel
+by synchronizing calls to `.clone()` (Thanks Austin Bonander for finding and
+reporting the issue).
+
+### Fixed
+
+- sync: synchronize `clone()` call in broadcast channel ([#7232])
+
+[#7232]: https://github.com/tokio-rs/tokio/pull/7232
+
 # 1.38.1 (July 16th, 2024)
 
 This release fixes the bug identified as ([#6682]), which caused timers not

tokio/Cargo.toml

@@ -173,3 +173,6 @@ allowed_external_types = [
   "bytes::buf::buf_mut::BufMut",
   "tokio_macros::*",
 ]
+
+[lints]
+workspace = true

tokio/src/runtime/tests/queue.rs

@@ -1,5 +1,4 @@
 use crate::runtime::scheduler::multi_thread::{queue, Stats};
-use crate::runtime::task::{self, Schedule, Task, TaskHarnessScheduleHooks};
 
 use std::cell::RefCell;
 use std::thread;
@@ -272,22 +271,3 @@ fn stress2() {
         assert_eq!(num_pop, NUM_TASKS);
     }
 }
-
-#[allow(dead_code)]
-struct Runtime;
-
-impl Schedule for Runtime {
-    fn release(&self, _task: &Task<Self>) -> Option<Task<Self>> {
-        None
-    }
-
-    fn schedule(&self, _task: task::Notified<Self>) {
-        unreachable!();
-    }
-
-    fn hooks(&self) -> TaskHarnessScheduleHooks {
-        TaskHarnessScheduleHooks {
-            task_terminate_callback: None,
-        }
-    }
-}

tokio/src/sync/broadcast.rs

@@ -118,7 +118,7 @@
 
 use crate::loom::cell::UnsafeCell;
 use crate::loom::sync::atomic::{AtomicBool, AtomicUsize};
-use crate::loom::sync::{Arc, Mutex, MutexGuard, RwLock, RwLockReadGuard};
+use crate::loom::sync::{Arc, Mutex, MutexGuard};
 use crate::runtime::coop::cooperative;
 use crate::util::linked_list::{self, GuardedLinkedList, LinkedList};
 use crate::util::WakeList;
@@ -304,7 +304,7 @@ use self::error::{RecvError, SendError, TryRecvError};
 /// Data shared between senders and receivers.
 struct Shared<T> {
     /// slots in the channel.
-    buffer: Box<[RwLock<Slot<T>>]>,
+    buffer: Box<[Mutex<Slot<T>>]>,
 
     /// Mask a position -> index.
     mask: usize,
@@ -348,7 +348,7 @@ struct Slot<T> {
     ///
     /// The value is set by `send` when the write lock is held. When a reader
     /// drops, `rem` is decremented. When it hits zero, the value is dropped.
-    val: UnsafeCell<Option<T>>,
+    val: Option<T>,
 }
 
 /// An entry in the wait queue.
@@ -386,7 +386,7 @@ generate_addr_of_methods! {
 }
 
 struct RecvGuard<'a, T> {
-    slot: RwLockReadGuard<'a, Slot<T>>,
+    slot: MutexGuard<'a, Slot<T>>,
 }
 
 /// Receive a value future.
@@ -395,11 +395,15 @@ struct Recv<'a, T> {
     receiver: &'a mut Receiver<T>,
 
     /// Entry in the waiter `LinkedList`.
-    waiter: UnsafeCell<Waiter>,
+    waiter: WaiterCell,
 }
 
-unsafe impl<'a, T: Send> Send for Recv<'a, T> {}
-unsafe impl<'a, T: Send> Sync for Recv<'a, T> {}
+// The wrapper around `UnsafeCell` isolates the unsafe impl `Send` and `Sync`
+// from `Recv`.
+struct WaiterCell(UnsafeCell<Waiter>);
+
+unsafe impl Send for WaiterCell {}
+unsafe impl Sync for WaiterCell {}
 
 /// Max number of receivers. Reserve space to lock.
 const MAX_RECEIVERS: usize = usize::MAX >> 2;
@@ -467,12 +471,6 @@ pub fn channel<T: Clone>(capacity: usize) -> (Sender<T>, Receiver<T>) {
     (tx, rx)
 }
 
-unsafe impl<T: Send> Send for Sender<T> {}
-unsafe impl<T: Send> Sync for Sender<T> {}
-
-unsafe impl<T: Send> Send for Receiver<T> {}
-unsafe impl<T: Send> Sync for Receiver<T> {}
-
 impl<T> Sender<T> {
     /// Creates the sending-half of the [`broadcast`] channel.
     ///
@@ -511,10 +509,10 @@ impl<T> Sender<T> {
         let mut buffer = Vec::with_capacity(capacity);
 
         for i in 0..capacity {
-            buffer.push(RwLock::new(Slot {
+            buffer.push(Mutex::new(Slot {
                 rem: AtomicUsize::new(0),
                 pos: (i as u64).wrapping_sub(capacity as u64),
-                val: UnsafeCell::new(None),
+                val: None,
             }));
         }
 
@@ -600,7 +598,7 @@ impl<T> Sender<T> {
         tail.pos = tail.pos.wrapping_add(1);
 
         // Get the slot
-        let mut slot = self.shared.buffer[idx].write();
+        let mut slot = self.shared.buffer[idx].lock();
 
         // Track the position
         slot.pos = pos;
@@ -609,7 +607,7 @@ impl<T> Sender<T> {
         slot.rem.with_mut(|v| *v = rem);
 
         // Write the value
-        slot.val = UnsafeCell::new(Some(value));
+        slot.val = Some(value);
 
         // Release the slot lock before notifying the receivers.
         drop(slot);
@@ -696,7 +694,7 @@ impl<T> Sender<T> {
         while low < high {
             let mid = low + (high - low) / 2;
             let idx = base_idx.wrapping_add(mid) & self.shared.mask;
-            if self.shared.buffer[idx].read().rem.load(SeqCst) == 0 {
+            if self.shared.buffer[idx].lock().rem.load(SeqCst) == 0 {
                 low = mid + 1;
             } else {
                 high = mid;
@@ -738,7 +736,7 @@ impl<T> Sender<T> {
         let tail = self.shared.tail.lock();
 
         let idx = (tail.pos.wrapping_sub(1) & self.shared.mask as u64) as usize;
-        self.shared.buffer[idx].read().rem.load(SeqCst) == 0
+        self.shared.buffer[idx].lock().rem.load(SeqCst) == 0
     }
 
     /// Returns the number of active receivers.
@@ -1058,7 +1056,7 @@ impl<T> Receiver<T> {
         let idx = (self.next & self.shared.mask as u64) as usize;
 
         // The slot holding the next value to read
-        let mut slot = self.shared.buffer[idx].read();
+        let mut slot = self.shared.buffer[idx].lock();
 
         if slot.pos != self.next {
             // Release the `slot` lock before attempting to acquire the `tail`
@@ -1075,7 +1073,7 @@ impl<T> Receiver<T> {
             let mut tail = self.shared.tail.lock();
 
             // Acquire slot lock again
-            slot = self.shared.buffer[idx].read();
+            slot = self.shared.buffer[idx].lock();
 
             // Make sure the position did not change. This could happen in the
             // unlikely event that the buffer is wrapped between dropping the
@@ -1367,12 +1365,12 @@ impl<'a, T> Recv<'a, T> {
     fn new(receiver: &'a mut Receiver<T>) -> Recv<'a, T> {
         Recv {
             receiver,
-            waiter: UnsafeCell::new(Waiter {
+            waiter: WaiterCell(UnsafeCell::new(Waiter {
                 queued: AtomicBool::new(false),
                 waker: None,
                 pointers: linked_list::Pointers::new(),
                 _p: PhantomPinned,
-            }),
+            })),
         }
     }
 
@@ -1384,7 +1382,7 @@ impl<'a, T> Recv<'a, T> {
             is_unpin::<&mut Receiver<T>>();
 
             let me = self.get_unchecked_mut();
-            (me.receiver, &me.waiter)
+            (me.receiver, &me.waiter.0)
         }
     }
 }
@@ -1418,6 +1416,7 @@ impl<'a, T> Drop for Recv<'a, T> {
         // `Shared::notify_rx` before we drop the object.
         let queued = self
             .waiter
+            .0
             .with(|ptr| unsafe { (*ptr).queued.load(Acquire) });
 
         // If the waiter is queued, we need to unlink it from the waiters list.
@@ -1432,6 +1431,7 @@ impl<'a, T> Drop for Recv<'a, T> {
             // `Relaxed` order suffices because we hold the tail lock.
             let queued = self
                 .waiter
+                .0
                 .with_mut(|ptr| unsafe { (*ptr).queued.load(Relaxed) });
 
             if queued {
@@ -1440,7 +1440,7 @@ impl<'a, T> Drop for Recv<'a, T> {
                 // safety: tail lock is held and the wait node is verified to be in
                 // the list.
                 unsafe {
-                    self.waiter.with_mut(|ptr| {
+                    self.waiter.0.with_mut(|ptr| {
                         tail.waiters.remove((&mut *ptr).into());
                     });
                 }
@@ -1486,7 +1486,7 @@ impl<'a, T> RecvGuard<'a, T> {
     where
         T: Clone,
     {
-        self.slot.val.with(|ptr| unsafe { (*ptr).clone() })
+        self.slot.val.clone()
     }
 }
 
@@ -1494,8 +1494,7 @@ impl<'a, T> Drop for RecvGuard<'a, T> {
     fn drop(&mut self) {
         // Decrement the remaining counter
         if 1 == self.slot.rem.fetch_sub(1, SeqCst) {
-            // Safety: Last receiver, drop the value
-            self.slot.val.with_mut(|ptr| unsafe { *ptr = None });
+            self.slot.val = None;
         }
     }
 }