diff --git a/Cargo.lock b/Cargo.lock
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -972,13 +972,13 @@
  "cfg-if 1.0.0",
 ]
 
 [[package]]
 name = "crossbeam-channel"
-version = "0.5.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e54ea8bc3fb1ee042f5aace6e3c6e025d3874866da222930f70ce62aceba0bfa"
+version = "0.5.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5aaa7bd5fb665c6864b5f963dd9097905c54125909c7aa94c9e18507cdbe6c53"
 dependencies = [
  "cfg-if 1.0.0",
  "crossbeam-utils 0.8.6",
 ]
 
diff --git a/third_party/rust/crossbeam-channel/.cargo-checksum.json b/third_party/rust/crossbeam-channel/.cargo-checksum.json
--- a/third_party/rust/crossbeam-channel/.cargo-checksum.json
+++ b/third_party/rust/crossbeam-channel/.cargo-checksum.json
@@ -1 +1 @@
-{"files":{"CHANGELOG.md":"e70d1a5fa6697a8b24e193e3934975317df12279c167b90fcb9616291792197c","Cargo.lock":"0f4e59f28bdd52c4781d102fc7d1f16d1ea417aaec0a4846432444a4019b2537","Cargo.toml":"c8334f658b699a1a0e25d997d752a9493a627f9ddcb7aab739c7319ea583882f","LICENSE-APACHE":"a60eea817514531668d7e00765731449fe14d059d3249e0bc93b36de45f759f2","LICENSE-MIT":"5734ed989dfca1f625b40281ee9f4530f91b2411ec01cb748223e7eb87e201ab","LICENSE-THIRD-PARTY":"b16db96b93b1d7cf7bea533f572091ec6bca3234fbe0a83038be772ff391a44c","README.md":"415a71d4978cfd338a6ae1f1b41284652eccd277a815542c304647dc437a8274","benches/crossbeam.rs":"96cb1abd23cac3ef8a7174a802e94609926b555bb02c9658c78723d433f1dd92","examples/fibonacci.rs":"4e88fa40048cdc31e9c7bb60347d46f92543d7ddf39cab3b52bfe44affdb6a02","examples/matching.rs":"63c250e164607a7a9f643d46f107bb5da846d49e89cf9069909562d20e530f71","examples/stopwatch.rs":"d02121258f08d56f1eb7997e19bcb9bacb6836cfa0abbba90a9e59d8a50ae5cf","src/channel.rs":"a9baaad2f414c38cd324a60ac9375ca58462ce6662217683648e9b66cec43a8c","src/context.rs":"ff4d39639ddf16aaab582d4a5f3d10ef2c71afe1abbf4e60f3d9d2ddbd72c230","src/counter.rs":"c49a9f44587888850edeb62f7c8ecd1acecb39c836834254ff3ac934c478440a","src/err.rs":"fdbde7279a1e74973e5c7d3e835a97836229a357fe465c0ba1a37f2a012d1bef","src/flavors/array.rs":"853c2ad068f912cfb49877bcd41e241f34b25026b709bf0629523f19952e3adc","src/flavors/at.rs":"65bf870b3ddb14738256706b0276f2656ad1fe9cd8eb91737489868edd088e92","src/flavors/list.rs":"50dbe59616c39b5aa184470023ce0cfb1cb0dbd92e1577375d299446981527c0","src/flavors/mod.rs":"3d9d43bc38b0adb18c96c995c2bd3421d8e33ab6c30b20c3c467d21d48e485dc","src/flavors/never.rs":"0e7921922d00c711552fb063c63c78192fa6ddc0762fb81c1713b847495ec39a","src/flavors/tick.rs":"38a479b9f4a72a5ccb9c407a1e7b44d36b6ad0f4e214e39266b12b9564c803dc","src/flavors/zero.rs":"012a53f56b86df22ce49866da95e5f457fb99a18a098f0f64779c6d1cdd7092f","src/lib.rs":"3a65706d4124844ffc4c8cb1f8cc779631ec94f449f85cbb68364ad3619404f1","src/select.rs":"66eb10a6cbdf8dd0869f2a7cac9992fdaee36c9e2a01d708d39d7c794572935b","src/select_macro.rs":"96bc9acb9a22588a4e733b0ab0761ad2be9a6b3e03744e8fc9c6de9ae433b696","src/utils.rs":"746fe315d6cfc832e3dda35e5055c0fd5c99907f1303b2ea7eacc4e37c8527e1","src/waker.rs":"591ee70bf62ccad5aa2fac7b92d444183b02790a79c024f016c78de2396d08a3","tests/after.rs":"0154a8e152880db17a20514ecdd49dabc361d3629858d119b9746b5e932c780c","tests/array.rs":"e5f25e8991863a9a86d61a66be646d04feae527f35b1697fd215b97af4383736","tests/golang.rs":"dc85669c9c4e902b1bb263d00f5cb6f9ecb6d42b19fe53425b55ce97c887da49","tests/iter.rs":"25dc02135bbae9d47a30f9047661648e66bdc134e40ba78bc2fbacbb8b3819bc","tests/list.rs":"de865ef097f3bcb35c1c814554e6108fed43b3dbb1533c8bbcf8688cceb6b6ab","tests/mpsc.rs":"401aa3c6923815058881ddce98070df68ebab283913c89c007436bb8af7ca0ea","tests/never.rs":"ee40c4fc4dd5af4983fae8de6927f52b81174d222c162f745b26c4a6c7108e4f","tests/ready.rs":"d349702f123925a0781b48d677e6dcf64fc5d1fc788a7bf1e151a3d57e81871c","tests/same_channel.rs":"2bab761443671e841e1b2476bd8082d75533a2f6be7946f5dbcee67cdc82dccb","tests/select.rs":"d20259a45f387cbce80c2c876ae81ea3883f36ea01c5151c159d58c362f6ba07","tests/select_macro.rs":"d3af2dc98e0dd03dc4ffab464b8ccb2f8b7504e8bb830948a04c015b92f0b296","tests/thread_locals.rs":"a1ce59e2aff69161621c0cb215eb6ea238088c06a31a8507a74cf179fd5a4299","tests/tick.rs":"5f697bd14c48505d932e82065b5302ef668e1cc19cac18e8ac22e0c83c221c1d","tests/zero.rs":"afbd838001d4196daddf17133e60ccea31529cc48ee01e245ac0d6366d1e30b9"},"package":"e54ea8bc3fb1ee042f5aace6e3c6e025d3874866da222930f70ce62aceba0bfa"}
\ No newline at end of file
+{"files":{"CHANGELOG.md":"0f549e63930d1e576f117ee9249c84276eadbe6fb95818680c042c6c0af8a807","Cargo.lock":"834da9468c17c8e1b7fe457764257f4dfdaa24bc98cbdfedf3af4f3d4f5c1e6a","Cargo.toml":"1296a016c4c23d38a35b3d737ee8285fcaaf7d23b7bbb5a3484cefe56b7ca32a","LICENSE-APACHE":"a60eea817514531668d7e00765731449fe14d059d3249e0bc93b36de45f759f2","LICENSE-MIT":"5734ed989dfca1f625b40281ee9f4530f91b2411ec01cb748223e7eb87e201ab","LICENSE-THIRD-PARTY":"b16db96b93b1d7cf7bea533f572091ec6bca3234fbe0a83038be772ff391a44c","README.md":"415a71d4978cfd338a6ae1f1b41284652eccd277a815542c304647dc437a8274","benches/crossbeam.rs":"96cb1abd23cac3ef8a7174a802e94609926b555bb02c9658c78723d433f1dd92","examples/fibonacci.rs":"4e88fa40048cdc31e9c7bb60347d46f92543d7ddf39cab3b52bfe44affdb6a02","examples/matching.rs":"63c250e164607a7a9f643d46f107bb5da846d49e89cf9069909562d20e530f71","examples/stopwatch.rs":"d02121258f08d56f1eb7997e19bcb9bacb6836cfa0abbba90a9e59d8a50ae5cf","src/channel.rs":"3bbf69df6c3f0071a44bab0139a749447604f5ffa5e45acc2998803dee066522","src/context.rs":"ff4d39639ddf16aaab582d4a5f3d10ef2c71afe1abbf4e60f3d9d2ddbd72c230","src/counter.rs":"c49a9f44587888850edeb62f7c8ecd1acecb39c836834254ff3ac934c478440a","src/err.rs":"44cb2024ee6b0cd6fd24996430e53720769f64b4ac35016bc3e05cb9db48681d","src/flavors/array.rs":"0743fb71a8adc8d95143b1cdae996823dddb7ab7fb7139eb6e0cdf733ff231ee","src/flavors/at.rs":"1db64919593b7c14f838c16a22732515f1e716d2d5f6cc639f42631380e545cd","src/flavors/list.rs":"017b66a84ada393d11d1730297426338244b115944a4d631573447641a66bed6","src/flavors/mod.rs":"3d9d43bc38b0adb18c96c995c2bd3421d8e33ab6c30b20c3c467d21d48e485dc","src/flavors/never.rs":"747da857aa1a7601641f23f4930e6ad00ebaf50456d9be5c7aa270e2ecc24dcb","src/flavors/tick.rs":"69b2dfe0186bc8b9fd7a73e32da59d2656d8150da1e00fba92a412e0907568a3","src/flavors/zero.rs":"1edd8e5114daa5b82ec9f4a715c0389a9de02cce64de0f71b4225868dad99a99","src/lib.rs":"3a65706d4124844ffc4c8cb1f8cc779631ec94f449f85cbb68364ad3619404f1","src/select.rs":"63dbfde7098dac1424f1cc884f6b8364f3bf3e06527691dde628ff6c416a7f35","src/select_macro.rs":"582a033cc0a51917fd5197dfb66677e9d7982c013414e75ae78b4a740189a56d","src/utils.rs":"b4d38e39a7d7774729458b1b39253377a55657d377c483d30b32e42a0a0092e3","src/waker.rs":"2114bd84f35b2c654d1914127e0380e17a5c20d8ec1e20449af3d653cad27c64","tests/after.rs":"0154a8e152880db17a20514ecdd49dabc361d3629858d119b9746b5e932c780c","tests/array.rs":"e0f3814328c79727a85df3aee0409701849dabfeaaa2f70721e14396fbaba1cd","tests/golang.rs":"dc85669c9c4e902b1bb263d00f5cb6f9ecb6d42b19fe53425b55ce97c887da49","tests/iter.rs":"25dc02135bbae9d47a30f9047661648e66bdc134e40ba78bc2fbacbb8b3819bc","tests/list.rs":"de865ef097f3bcb35c1c814554e6108fed43b3dbb1533c8bbcf8688cceb6b6ab","tests/mpsc.rs":"401aa3c6923815058881ddce98070df68ebab283913c89c007436bb8af7ca0ea","tests/never.rs":"ee40c4fc4dd5af4983fae8de6927f52b81174d222c162f745b26c4a6c7108e4f","tests/ready.rs":"d349702f123925a0781b48d677e6dcf64fc5d1fc788a7bf1e151a3d57e81871c","tests/same_channel.rs":"2bab761443671e841e1b2476bd8082d75533a2f6be7946f5dbcee67cdc82dccb","tests/select.rs":"d20259a45f387cbce80c2c876ae81ea3883f36ea01c5151c159d58c362f6ba07","tests/select_macro.rs":"948eb21f72a9317c0de98a9bd21f6f8ff2b09b73b45c171c45b04c051a2fd0c4","tests/thread_locals.rs":"a1ce59e2aff69161621c0cb215eb6ea238088c06a31a8507a74cf179fd5a4299","tests/tick.rs":"5f697bd14c48505d932e82065b5302ef668e1cc19cac18e8ac22e0c83c221c1d","tests/zero.rs":"afbd838001d4196daddf17133e60ccea31529cc48ee01e245ac0d6366d1e30b9"},"package":"5aaa7bd5fb665c6864b5f963dd9097905c54125909c7aa94c9e18507cdbe6c53"}
\ No newline at end of file
diff --git a/third_party/rust/crossbeam-channel/CHANGELOG.md b/third_party/rust/crossbeam-channel/CHANGELOG.md
--- a/third_party/rust/crossbeam-channel/CHANGELOG.md
+++ b/third_party/rust/crossbeam-channel/CHANGELOG.md
@@ -1,8 +1,16 @@
+# Version 0.5.4
+
+- Workaround a bug in upstream related to TLS access on AArch64 Linux. (#802)
+
+# Version 0.5.3
+
+- Fix panic on very large timeout. (#798)
+
 # Version 0.5.2
 
-- Fix stacked borrows violations. (#763, #764)
+- Fix stacked borrows violations when `-Zmiri-tag-raw-pointers` is enabled. (#763, #764)
 
 # Version 0.5.1
 
 - Fix memory leak in unbounded channel. (#669)
 
@@ -19,10 +27,12 @@
 
 - Fix bug in release (yanking 0.4.3)
 - Fix UB and breaking change introduced in 0.4.3
 
 # Version 0.4.3
+
+**Note**: This release has been yanked. See [CVE-2020-15254](https://github.com/crossbeam-rs/crossbeam/security/advisories/GHSA-v5m7-53cv-f3hx) for details.
 
 - Change license to "MIT OR Apache-2.0".
 
 # Version 0.4.2
 
diff --git a/third_party/rust/crossbeam-channel/Cargo.lock b/third_party/rust/crossbeam-channel/Cargo.lock
--- a/third_party/rust/crossbeam-channel/Cargo.lock
+++ b/third_party/rust/crossbeam-channel/Cargo.lock
@@ -8,34 +8,34 @@
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
 [[package]]
 name = "crossbeam-channel"
-version = "0.5.2"
+version = "0.5.4"
 dependencies = [
  "cfg-if",
  "crossbeam-utils",
  "num_cpus",
  "rand",
  "signal-hook",
 ]
 
 [[package]]
 name = "crossbeam-utils"
-version = "0.8.6"
+version = "0.8.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cfcae03edb34f947e64acdb1c33ec169824e20657e9ecb61cef6c8c74dcb8120"
+checksum = "0bf124c720b7686e3c2663cf54062ab0f68a88af2fb6a030e87e30bf721fcb38"
 dependencies = [
  "cfg-if",
  "lazy_static",
 ]
 
 [[package]]
 name = "getrandom"
-version = "0.2.3"
+version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7fcd999463524c52659517fe2cea98493cfe485d10565e7b0fb07dbba7ad2753"
+checksum = "d39cd93900197114fa1fcb7ae84ca742095eed9442088988ae74fa744e930e77"
 dependencies = [
  "cfg-if",
  "libc",
  "wasi",
 ]
@@ -55,13 +55,13 @@
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.112"
+version = "0.2.120"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1b03d17f364a3a042d5e5d46b053bbbf82c92c9430c592dd4c064dc6ee997125"
+checksum = "ad5c14e80759d0939d013e6ca49930e59fc53dd8e5009132f76240c179380c09"
 
 [[package]]
 name = "num_cpus"
 version = "1.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -77,18 +77,17 @@
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "eb9f9e6e233e5c4a35559a617bf40a4ec447db2e84c20b55a6f83167b7e57872"
 
 [[package]]
 name = "rand"
-version = "0.8.4"
+version = "0.8.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2e7573632e6454cf6b99d7aac4ccca54be06da05aca2ef7423d22d27d4d4bcd8"
+checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
 dependencies = [
  "libc",
  "rand_chacha",
  "rand_core",
- "rand_hc",
 ]
 
 [[package]]
 name = "rand_chacha"
 version = "0.3.1"
@@ -104,19 +103,10 @@
 version = "0.6.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d34f1408f55294453790c48b2f1ebbb1c5b4b7563eb1f418bcfcfdbb06ebb4e7"
 dependencies = [
  "getrandom",
-]
-
-[[package]]
-name = "rand_hc"
-version = "0.3.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d51e9f596de227fda2ea6c84607f5558e196eeaf43c986b724ba4fb8fdf497e7"
-dependencies = [
- "rand_core",
 ]
 
 [[package]]
 name = "signal-hook"
 version = "0.3.13"
diff --git a/third_party/rust/crossbeam-channel/Cargo.toml b/third_party/rust/crossbeam-channel/Cargo.toml
--- a/third_party/rust/crossbeam-channel/Cargo.toml
+++ b/third_party/rust/crossbeam-channel/Cargo.toml
@@ -11,24 +11,36 @@
 
 [package]
 edition = "2018"
 rust-version = "1.36"
 name = "crossbeam-channel"
-version = "0.5.2"
+version = "0.5.4"
 description = "Multi-producer multi-consumer channels for message passing"
 homepage = "https://github.com/crossbeam-rs/crossbeam/tree/master/crossbeam-channel"
-keywords = ["channel", "mpmc", "select", "golang", "message"]
-categories = ["algorithms", "concurrency", "data-structures"]
+keywords = [
+    "channel",
+    "mpmc",
+    "select",
+    "golang",
+    "message",
+]
+categories = [
+    "algorithms",
+    "concurrency",
+    "data-structures",
+]
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/crossbeam-rs/crossbeam"
+
 [dependencies.cfg-if]
 version = "1"
 
 [dependencies.crossbeam-utils]
 version = "0.8"
 optional = true
 default-features = false
+
 [dev-dependencies.num_cpus]
 version = "1.13.0"
 
 [dev-dependencies.rand]
 version = "0.8"
diff --git a/third_party/rust/crossbeam-channel/src/channel.rs b/third_party/rust/crossbeam-channel/src/channel.rs
--- a/third_party/rust/crossbeam-channel/src/channel.rs
+++ b/third_party/rust/crossbeam-channel/src/channel.rs
@@ -12,10 +12,11 @@
 use crate::err::{
     RecvError, RecvTimeoutError, SendError, SendTimeoutError, TryRecvError, TrySendError,
 };
 use crate::flavors;
 use crate::select::{Operation, SelectHandle, Token};
+use crate::utils;
 
 /// Creates a channel of unbounded capacity.
 ///
 /// This channel has a growable buffer that can hold any number of messages at a time.
 ///
@@ -469,11 +470,11 @@
     ///     s.send_timeout(3, Duration::from_millis(500)),
     ///     Err(SendTimeoutError::Disconnected(3)),
     /// );
     /// ```
     pub fn send_timeout(&self, msg: T, timeout: Duration) -> Result<(), SendTimeoutError<T>> {
-        self.send_deadline(msg, Instant::now() + timeout)
+        self.send_deadline(msg, utils::convert_timeout_to_deadline(timeout))
     }
 
     /// Waits for a message to be sent into the channel, but only until a given deadline.
     ///
     /// If the channel is full and not disconnected, this call will block until the send operation
@@ -859,11 +860,11 @@
     ///     r.recv_timeout(Duration::from_secs(1)),
     ///     Err(RecvTimeoutError::Disconnected),
     /// );
     /// ```
     pub fn recv_timeout(&self, timeout: Duration) -> Result<T, RecvTimeoutError> {
-        self.recv_deadline(Instant::now() + timeout)
+        self.recv_deadline(utils::convert_timeout_to_deadline(timeout))
     }
 
     /// Waits for a message to be received from the channel, but only before a given deadline.
     ///
     /// If the channel is empty and not disconnected, this call will block until the receive
diff --git a/third_party/rust/crossbeam-channel/src/err.rs b/third_party/rust/crossbeam-channel/src/err.rs
--- a/third_party/rust/crossbeam-channel/src/err.rs
+++ b/third_party/rust/crossbeam-channel/src/err.rs
@@ -306,20 +306,18 @@
     }
 }
 
 impl TryRecvError {
     /// Returns `true` if the receive operation failed because the channel is empty.
-    #[allow(clippy::trivially_copy_pass_by_ref)]
     pub fn is_empty(&self) -> bool {
         match self {
             TryRecvError::Empty => true,
             _ => false,
         }
     }
 
     /// Returns `true` if the receive operation failed because the channel is disconnected.
-    #[allow(clippy::trivially_copy_pass_by_ref)]
     pub fn is_disconnected(&self) -> bool {
         match self {
             TryRecvError::Disconnected => true,
             _ => false,
         }
@@ -345,20 +343,18 @@
     }
 }
 
 impl RecvTimeoutError {
     /// Returns `true` if the receive operation timed out.
-    #[allow(clippy::trivially_copy_pass_by_ref)]
     pub fn is_timeout(&self) -> bool {
         match self {
             RecvTimeoutError::Timeout => true,
             _ => false,
         }
     }
 
     /// Returns `true` if the receive operation failed because the channel is disconnected.
-    #[allow(clippy::trivially_copy_pass_by_ref)]
     pub fn is_disconnected(&self) -> bool {
         match self {
             RecvTimeoutError::Disconnected => true,
             _ => false,
         }
diff --git a/third_party/rust/crossbeam-channel/src/flavors/array.rs b/third_party/rust/crossbeam-channel/src/flavors/array.rs
--- a/third_party/rust/crossbeam-channel/src/flavors/array.rs
+++ b/third_party/rust/crossbeam-channel/src/flavors/array.rs
@@ -7,11 +7,10 @@
 //! Source:
 //!   - <http://www.1024cores.net/home/lock-free-algorithms/queues/bounded-mpmc-queue>
 //!   - <https://docs.google.com/document/d/1yIAYmbvL3JxOKOjuCyon7JhW4cSv1wy5hC0ApeGMV9s/pub>
 
 use std::cell::UnsafeCell;
-use std::marker::PhantomData;
 use std::mem::MaybeUninit;
 use std::ptr;
 use std::sync::atomic::{self, AtomicUsize, Ordering};
 use std::time::Instant;
 
@@ -31,11 +30,11 @@
     msg: UnsafeCell<MaybeUninit<T>>,
 }
 
 /// The token type for the array flavor.
 #[derive(Debug)]
-pub struct ArrayToken {
+pub(crate) struct ArrayToken {
     /// Slot to read from or write to.
     slot: *const u8,
 
     /// Stamp to store into the slot after reading or writing.
     stamp: usize,
@@ -70,11 +69,11 @@
     ///
     /// Messages are pushed into the tail of the channel.
     tail: CachePadded<AtomicUsize>,
 
     /// The buffer holding slots.
-    buffer: *mut Slot<T>,
+    buffer: Box<[Slot<T>]>,
 
     /// The channel capacity.
     cap: usize,
 
     /// A stamp with the value of `{ lap: 1, mark: 0, index: 0 }`.
@@ -86,13 +85,10 @@
     /// Senders waiting while the channel is full.
     senders: SyncWaker,
 
     /// Receivers waiting while the channel is empty and not disconnected.
     receivers: SyncWaker,
-
-    /// Indicates that dropping a `Channel<T>` may drop values of type `T`.
-    _marker: PhantomData<T>,
 }
 
 impl<T> Channel<T> {
     /// Creates a bounded channel of capacity `cap`.
     pub(crate) fn with_capacity(cap: usize) -> Self {
@@ -107,33 +103,29 @@
         // Tail is initialized to `{ lap: 0, mark: 0, index: 0 }`.
         let tail = 0;
 
         // Allocate a buffer of `cap` slots initialized
         // with stamps.
-        let buffer = {
-            let boxed: Box<[Slot<T>]> = (0..cap)
-                .map(|i| {
-                    // Set the stamp to `{ lap: 0, mark: 0, index: i }`.
-                    Slot {
-                        stamp: AtomicUsize::new(i),
-                        msg: UnsafeCell::new(MaybeUninit::uninit()),
-                    }
-                })
-                .collect();
-            Box::into_raw(boxed) as *mut Slot<T>
-        };
+        let buffer: Box<[Slot<T>]> = (0..cap)
+            .map(|i| {
+                // Set the stamp to `{ lap: 0, mark: 0, index: i }`.
+                Slot {
+                    stamp: AtomicUsize::new(i),
+                    msg: UnsafeCell::new(MaybeUninit::uninit()),
+                }
+            })
+            .collect();
 
         Channel {
             buffer,
             cap,
             one_lap,
             mark_bit,
             head: CachePadded::new(AtomicUsize::new(head)),
             tail: CachePadded::new(AtomicUsize::new(tail)),
             senders: SyncWaker::new(),
             receivers: SyncWaker::new(),
-            _marker: PhantomData,
         }
     }
 
     /// Returns a receiver handle to the channel.
     pub(crate) fn receiver(&self) -> Receiver<'_, T> {
@@ -161,11 +153,12 @@
             // Deconstruct the tail.
             let index = tail & (self.mark_bit - 1);
             let lap = tail & !(self.one_lap - 1);
 
             // Inspect the corresponding slot.
-            let slot = unsafe { &*self.buffer.add(index) };
+            debug_assert!(index < self.buffer.len());
+            let slot = unsafe { self.buffer.get_unchecked(index) };
             let stamp = slot.stamp.load(Ordering::Acquire);
 
             // If the tail and the stamp match, we may attempt to push.
             if tail == stamp {
                 let new_tail = if index + 1 < self.cap {
@@ -243,11 +236,12 @@
             // Deconstruct the head.
             let index = head & (self.mark_bit - 1);
             let lap = head & !(self.one_lap - 1);
 
             // Inspect the corresponding slot.
-            let slot = unsafe { &*self.buffer.add(index) };
+            debug_assert!(index < self.buffer.len());
+            let slot = unsafe { self.buffer.get_unchecked(index) };
             let stamp = slot.stamp.load(Ordering::Acquire);
 
             // If the the stamp is ahead of the head by 1, we may attempt to pop.
             if head + 1 == stamp {
                 let new = if index + 1 < self.cap {
@@ -473,11 +467,10 @@
             }
         }
     }
 
     /// Returns the capacity of the channel.
-    #[allow(clippy::unnecessary_wraps)] // This is intentional.
     pub(crate) fn capacity(&self) -> Option<usize> {
         Some(self.cap)
     }
 
     /// Disconnects the channel and wakes up all blocked senders and receivers.
@@ -538,26 +531,15 @@
             } else {
                 hix + i - self.cap
             };
 
             unsafe {
-                let p = {
-                    let slot = &mut *self.buffer.add(index);
-                    let msg = &mut *slot.msg.get();
-                    msg.as_mut_ptr()
-                };
-                p.drop_in_place();
-            }
-        }
-
-        // Finally, deallocate the buffer, but don't run any destructors.
-        unsafe {
-            // Create a slice from the buffer to make
-            // a fat pointer. Then, use Box::from_raw
-            // to deallocate it.
-            let ptr = std::slice::from_raw_parts_mut(self.buffer, self.cap) as *mut [Slot<T>];
-            Box::from_raw(ptr);
+                debug_assert!(index < self.buffer.len());
+                let slot = self.buffer.get_unchecked_mut(index);
+                let msg = &mut *slot.msg.get();
+                msg.as_mut_ptr().drop_in_place();
+            }
         }
     }
 }
 
 /// Receiver handle to a channel.
diff --git a/third_party/rust/crossbeam-channel/src/flavors/at.rs b/third_party/rust/crossbeam-channel/src/flavors/at.rs
--- a/third_party/rust/crossbeam-channel/src/flavors/at.rs
+++ b/third_party/rust/crossbeam-channel/src/flavors/at.rs
@@ -33,11 +33,11 @@
         }
     }
     /// Creates a channel that delivers a message after a certain duration of time.
     #[inline]
     pub(crate) fn new_timeout(dur: Duration) -> Self {
-        Self::new_deadline(Instant::now() + dur)
+        Self::new_deadline(utils::convert_timeout_to_deadline(dur))
     }
 
     /// Attempts to receive a message without blocking.
     #[inline]
     pub(crate) fn try_recv(&self) -> Result<Instant, TryRecvError> {
@@ -140,11 +140,10 @@
             1
         }
     }
 
     /// Returns the capacity of the channel.
-    #[allow(clippy::unnecessary_wraps)] // This is intentional.
     #[inline]
     pub(crate) fn capacity(&self) -> Option<usize> {
         Some(1)
     }
 }
diff --git a/third_party/rust/crossbeam-channel/src/flavors/list.rs b/third_party/rust/crossbeam-channel/src/flavors/list.rs
--- a/third_party/rust/crossbeam-channel/src/flavors/list.rs
+++ b/third_party/rust/crossbeam-channel/src/flavors/list.rs
@@ -124,11 +124,11 @@
     block: AtomicPtr<Block<T>>,
 }
 
 /// The token type for the list flavor.
 #[derive(Debug)]
-pub struct ListToken {
+pub(crate) struct ListToken {
     /// The block of slots.
     block: *const u8,
 
     /// The offset into the block.
     offset: usize,
diff --git a/third_party/rust/crossbeam-channel/src/flavors/never.rs b/third_party/rust/crossbeam-channel/src/flavors/never.rs
--- a/third_party/rust/crossbeam-channel/src/flavors/never.rs
+++ b/third_party/rust/crossbeam-channel/src/flavors/never.rs
@@ -63,11 +63,10 @@
     pub(crate) fn len(&self) -> usize {
         0
     }
 
     /// Returns the capacity of the channel.
-    #[allow(clippy::unnecessary_wraps)] // This is intentional.
     #[inline]
     pub(crate) fn capacity(&self) -> Option<usize> {
         Some(0)
     }
 }
diff --git a/third_party/rust/crossbeam-channel/src/flavors/tick.rs b/third_party/rust/crossbeam-channel/src/flavors/tick.rs
--- a/third_party/rust/crossbeam-channel/src/flavors/tick.rs
+++ b/third_party/rust/crossbeam-channel/src/flavors/tick.rs
@@ -8,10 +8,11 @@
 use crossbeam_utils::atomic::AtomicCell;
 
 use crate::context::Context;
 use crate::err::{RecvTimeoutError, TryRecvError};
 use crate::select::{Operation, SelectHandle, Token};
+use crate::utils;
 
 /// Result of a receive operation.
 pub(crate) type TickToken = Option<Instant>;
 
 /// Channel that delivers messages periodically.
@@ -26,11 +27,11 @@
 impl Channel {
     /// Creates a channel that delivers messages periodically.
     #[inline]
     pub(crate) fn new(dur: Duration) -> Self {
         Channel {
-            delivery_time: AtomicCell::new(Instant::now() + dur),
+            delivery_time: AtomicCell::new(utils::convert_timeout_to_deadline(dur)),
             duration: dur,
         }
     }
 
     /// Attempts to receive a message without blocking.
@@ -110,11 +111,10 @@
             1
         }
     }
 
     /// Returns the capacity of the channel.
-    #[allow(clippy::unnecessary_wraps)] // This is intentional.
     #[inline]
     pub(crate) fn capacity(&self) -> Option<usize> {
         Some(1)
     }
 }
diff --git a/third_party/rust/crossbeam-channel/src/flavors/zero.rs b/third_party/rust/crossbeam-channel/src/flavors/zero.rs
--- a/third_party/rust/crossbeam-channel/src/flavors/zero.rs
+++ b/third_party/rust/crossbeam-channel/src/flavors/zero.rs
@@ -15,11 +15,11 @@
 use crate::select::{Operation, SelectHandle, Selected, Token};
 use crate::utils::Spinlock;
 use crate::waker::Waker;
 
 /// A pointer to a packet.
-pub struct ZeroToken(*mut ());
+pub(crate) struct ZeroToken(*mut ());
 
 impl Default for ZeroToken {
     fn default() -> Self {
         Self(ptr::null_mut())
     }
@@ -361,11 +361,10 @@
     pub(crate) fn len(&self) -> usize {
         0
     }
 
     /// Returns the capacity of the channel.
-    #[allow(clippy::unnecessary_wraps)] // This is intentional.
     pub(crate) fn capacity(&self) -> Option<usize> {
         Some(0)
     }
 
     /// Returns `true` if the channel is empty.
diff --git a/third_party/rust/crossbeam-channel/src/select.rs b/third_party/rust/crossbeam-channel/src/select.rs
--- a/third_party/rust/crossbeam-channel/src/select.rs
+++ b/third_party/rust/crossbeam-channel/src/select.rs
@@ -20,16 +20,17 @@
 ///
 /// Each field contains data associated with a specific channel flavor.
 // This is a private API that is used by the select macro.
 #[derive(Debug, Default)]
 pub struct Token {
-    pub at: flavors::at::AtToken,
-    pub array: flavors::array::ArrayToken,
-    pub list: flavors::list::ListToken,
-    pub never: flavors::never::NeverToken,
-    pub tick: flavors::tick::TickToken,
-    pub zero: flavors::zero::ZeroToken,
+    pub(crate) at: flavors::at::AtToken,
+    pub(crate) array: flavors::array::ArrayToken,
+    pub(crate) list: flavors::list::ListToken,
+    #[allow(dead_code)]
+    pub(crate) never: flavors::never::NeverToken,
+    pub(crate) tick: flavors::tick::TickToken,
+    pub(crate) zero: flavors::zero::ZeroToken,
 }
 
 /// Identifier associated with an operation by a specific thread on a specific channel.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct Operation(usize);
@@ -484,11 +485,11 @@
 #[inline]
 pub fn select_timeout<'a>(
     handles: &mut [(&'a dyn SelectHandle, usize, *const u8)],
     timeout: Duration,
 ) -> Result<SelectedOperation<'a>, SelectTimeoutError> {
-    select_deadline(handles, Instant::now() + timeout)
+    select_deadline(handles, utils::convert_timeout_to_deadline(timeout))
 }
 
 /// Blocks until a given deadline, or until one of the operations becomes ready and selects it.
 #[inline]
 pub(crate) fn select_deadline<'a>(
@@ -1040,11 +1041,11 @@
     ///     Ok(i) if i == oper2 => assert_eq!(r2.try_recv(), Ok(20)),
     ///     Ok(_) => unreachable!(),
     /// }
     /// ```
     pub fn ready_timeout(&mut self, timeout: Duration) -> Result<usize, ReadyTimeoutError> {
-        self.ready_deadline(Instant::now() + timeout)
+        self.ready_deadline(utils::convert_timeout_to_deadline(timeout))
     }
 
     /// Blocks until a given deadline, or until one of the operations becomes ready.
     ///
     /// If an operation becomes ready, its index is returned. If multiple operations are ready at
diff --git a/third_party/rust/crossbeam-channel/src/select_macro.rs b/third_party/rust/crossbeam-channel/src/select_macro.rs
--- a/third_party/rust/crossbeam-channel/src/select_macro.rs
+++ b/third_party/rust/crossbeam-channel/src/select_macro.rs
@@ -119,22 +119,11 @@
             ($($head)* $case ($($args)*) $(-> $res)* => { $body },)
         )
     };
     // Only one case remains.
     (@list
-        ($case:ident ($($args:tt)*) $(-> $res:pat)* => $body:expr)
-        ($($head:tt)*)
-    ) => {
-        $crate::crossbeam_channel_internal!(
-            @list
-            ()
-            ($($head)* $case ($($args)*) $(-> $res)* => { $body },)
-        )
-    };
-    // Accept a trailing comma at the end of the list.
-    (@list
-        ($case:ident ($($args:tt)*) $(-> $res:pat)* => $body:expr,)
+        ($case:ident ($($args:tt)*) $(-> $res:pat)* => $body:expr $(,)?)
         ($($head:tt)*)
     ) => {
         $crate::crossbeam_channel_internal!(
             @list
             ()
@@ -371,34 +360,21 @@
         )
     };
 
     // Check the format of a recv case.
     (@case
-        (recv($r:expr) -> $res:pat => $body:tt, $($tail:tt)*)
+        (recv($r:expr $(,)?) -> $res:pat => $body:tt, $($tail:tt)*)
         ($($cases:tt)*)
         $default:tt
     ) => {
         $crate::crossbeam_channel_internal!(
             @case
             ($($tail)*)
             ($($cases)* recv($r) -> $res => $body,)
             $default
         )
     };
-    // Allow trailing comma...
-    (@case
-        (recv($r:expr,) -> $res:pat => $body:tt, $($tail:tt)*)
-        ($($cases:tt)*)
-        $default:tt
-    ) => {
-        $crate::crossbeam_channel_internal!(
-            @case
-            ($($tail)*)
-            ($($cases)* recv($r) -> $res => $body,)
-            $default
-        )
-    };
     // Print an error if the argument list is invalid.
     (@case
         (recv($($args:tt)*) -> $res:pat => $body:tt, $($tail:tt)*)
         ($($cases:tt)*)
         $default:tt
@@ -426,34 +402,21 @@
         )
     };
 
     // Check the format of a send case.
     (@case
-        (send($s:expr, $m:expr) -> $res:pat => $body:tt, $($tail:tt)*)
+        (send($s:expr, $m:expr $(,)?) -> $res:pat => $body:tt, $($tail:tt)*)
         ($($cases:tt)*)
         $default:tt
     ) => {
         $crate::crossbeam_channel_internal!(
             @case
             ($($tail)*)
             ($($cases)* send($s, $m) -> $res => $body,)
             $default
         )
     };
-    // Allow trailing comma...
-    (@case
-        (send($s:expr, $m:expr,) -> $res:pat => $body:tt, $($tail:tt)*)
-        ($($cases:tt)*)
-        $default:tt
-    ) => {
-        $crate::crossbeam_channel_internal!(
-            @case
-            ($($tail)*)
-            ($($cases)* send($s, $m) -> $res => $body,)
-            $default
-        )
-    };
     // Print an error if the argument list is invalid.
     (@case
         (send($($args:tt)*) -> $res:pat => $body:tt, $($tail:tt)*)
         ($($cases:tt)*)
         $default:tt
@@ -494,24 +457,11 @@
             (default() => $body,)
         )
     };
     // Check the format of a default case with timeout.
     (@case
-        (default($timeout:expr) => $body:tt, $($tail:tt)*)
-        $cases:tt
-        ()
-    ) => {
-        $crate::crossbeam_channel_internal!(
-            @case
-            ($($tail)*)
-            $cases
-            (default($timeout) => $body,)
-        )
-    };
-    // Allow trailing comma...
-    (@case
-        (default($timeout:expr,) => $body:tt, $($tail:tt)*)
+        (default($timeout:expr $(,)?) => $body:tt, $($tail:tt)*)
         $cases:tt
         ()
     ) => {
         $crate::crossbeam_channel_internal!(
             @case
diff --git a/third_party/rust/crossbeam-channel/src/utils.rs b/third_party/rust/crossbeam-channel/src/utils.rs
--- a/third_party/rust/crossbeam-channel/src/utils.rs
+++ b/third_party/rust/crossbeam-channel/src/utils.rs
@@ -59,10 +59,18 @@
             }
         }
     }
 }
 
+// https://github.com/crossbeam-rs/crossbeam/issues/795
+pub(crate) fn convert_timeout_to_deadline(timeout: Duration) -> Instant {
+    match Instant::now().checked_add(timeout) {
+        Some(deadline) => deadline,
+        None => Instant::now() + Duration::from_secs(86400 * 365 * 30),
+    }
+}
+
 /// A simple spinlock.
 pub(crate) struct Spinlock<T> {
     flag: AtomicBool,
     value: UnsafeCell<T>,
 }
diff --git a/third_party/rust/crossbeam-channel/src/waker.rs b/third_party/rust/crossbeam-channel/src/waker.rs
--- a/third_party/rust/crossbeam-channel/src/waker.rs
+++ b/third_party/rust/crossbeam-channel/src/waker.rs
@@ -75,30 +75,36 @@
     }
 
     /// Attempts to find another thread's entry, select the operation, and wake it up.
     #[inline]
     pub(crate) fn try_select(&mut self) -> Option<Entry> {
-        self.selectors
-            .iter()
-            .position(|selector| {
-                // Does the entry belong to a different thread?
-                selector.cx.thread_id() != current_thread_id()
-                    && selector // Try selecting this operation.
-                        .cx
-                        .try_select(Selected::Operation(selector.oper))
-                        .is_ok()
-                    && {
-                        // Provide the packet.
-                        selector.cx.store_packet(selector.packet);
-                        // Wake the thread up.
-                        selector.cx.unpark();
-                        true
-                    }
-            })
-            // Remove the entry from the queue to keep it clean and improve
-            // performance.
-            .map(|pos| self.selectors.remove(pos))
+        if self.selectors.is_empty() {
+            None
+        } else {
+            let thread_id = current_thread_id();
+
+            self.selectors
+                .iter()
+                .position(|selector| {
+                    // Does the entry belong to a different thread?
+                    selector.cx.thread_id() != thread_id
+                        && selector // Try selecting this operation.
+                            .cx
+                            .try_select(Selected::Operation(selector.oper))
+                            .is_ok()
+                        && {
+                            // Provide the packet.
+                            selector.cx.store_packet(selector.packet);
+                            // Wake the thread up.
+                            selector.cx.unpark();
+                            true
+                        }
+                })
+                // Remove the entry from the queue to keep it clean and improve
+                // performance.
+                .map(|pos| self.selectors.remove(pos))
+        }
     }
 
     /// Returns `true` if there is an entry which can be selected by the current thread.
     #[inline]
     pub(crate) fn can_select(&self) -> bool {
diff --git a/third_party/rust/crossbeam-channel/tests/array.rs b/third_party/rust/crossbeam-channel/tests/array.rs
--- a/third_party/rust/crossbeam-channel/tests/array.rs
+++ b/third_party/rust/crossbeam-channel/tests/array.rs
@@ -1,8 +1,6 @@
 //! Tests for the array channel flavor.
-
-#![cfg(not(miri))] // TODO: many assertions failed due to Miri is slow
 
 use std::any::Any;
 use std::sync::atomic::AtomicUsize;
 use std::sync::atomic::Ordering;
 use std::thread;
@@ -252,11 +250,17 @@
     assert_eq!(r.recv(), Err(RecvError));
 }
 
 #[test]
 fn len() {
+    #[cfg(miri)]
+    const COUNT: usize = 250;
+    #[cfg(not(miri))]
     const COUNT: usize = 25_000;
+    #[cfg(miri)]
+    const CAP: usize = 100;
+    #[cfg(not(miri))]
     const CAP: usize = 1000;
 
     let (s, r) = bounded(CAP);
 
     assert_eq!(s.len(), 0);
@@ -345,10 +349,13 @@
     .unwrap();
 }
 
 #[test]
 fn spsc() {
+    #[cfg(miri)]
+    const COUNT: usize = 100;
+    #[cfg(not(miri))]
     const COUNT: usize = 100_000;
 
     let (s, r) = bounded(3);
 
     scope(|scope| {
@@ -367,10 +374,13 @@
     .unwrap();
 }
 
 #[test]
 fn mpmc() {
+    #[cfg(miri)]
+    const COUNT: usize = 100;
+    #[cfg(not(miri))]
     const COUNT: usize = 25_000;
     const THREADS: usize = 4;
 
     let (s, r) = bounded::<usize>(3);
     let v = (0..COUNT).map(|_| AtomicUsize::new(0)).collect::<Vec<_>>();
@@ -399,10 +409,13 @@
     }
 }
 
 #[test]
 fn stress_oneshot() {
+    #[cfg(miri)]
+    const COUNT: usize = 100;
+    #[cfg(not(miri))]
     const COUNT: usize = 10_000;
 
     for _ in 0..COUNT {
         let (s, r) = bounded(1);
 
@@ -414,10 +427,13 @@
     }
 }
 
 #[test]
 fn stress_iter() {
+    #[cfg(miri)]
+    const COUNT: usize = 100;
+    #[cfg(not(miri))]
     const COUNT: usize = 100_000;
 
     let (request_s, request_r) = bounded(1);
     let (response_s, response_r) = bounded(1);
 
@@ -479,10 +495,11 @@
         });
     })
     .unwrap();
 }
 
+#[cfg_attr(miri, ignore)] // Miri is too slow
 #[test]
 fn drops() {
     const RUNS: usize = 100;
 
     static DROPS: AtomicUsize = AtomicUsize::new(0);
@@ -531,10 +548,13 @@
     }
 }
 
 #[test]
 fn linearizable() {
+    #[cfg(miri)]
+    const COUNT: usize = 100;
+    #[cfg(not(miri))]
     const COUNT: usize = 25_000;
     const THREADS: usize = 4;
 
     let (s, r) = bounded(THREADS);
 
@@ -551,10 +571,13 @@
     .unwrap();
 }
 
 #[test]
 fn fairness() {
+    #[cfg(miri)]
+    const COUNT: usize = 100;
+    #[cfg(not(miri))]
     const COUNT: usize = 10_000;
 
     let (s1, r1) = bounded::<()>(COUNT);
     let (s2, r2) = bounded::<()>(COUNT);
 
@@ -573,10 +596,13 @@
     assert!(hits.iter().all(|x| *x >= COUNT / hits.len() / 2));
 }
 
 #[test]
 fn fairness_duplicates() {
+    #[cfg(miri)]
+    const COUNT: usize = 100;
+    #[cfg(not(miri))]
     const COUNT: usize = 10_000;
 
     let (s, r) = bounded::<()>(COUNT);
 
     for _ in 0..COUNT {
@@ -617,10 +643,13 @@
     }
 }
 
 #[test]
 fn channel_through_channel() {
+    #[cfg(miri)]
+    const COUNT: usize = 100;
+    #[cfg(not(miri))]
     const COUNT: usize = 1000;
 
     type T = Box<dyn Any + Send>;
 
     let (s, r) = bounded::<T>(1);
@@ -652,5 +681,58 @@
             }
         });
     })
     .unwrap();
 }
+
+#[test]
+fn panic_on_drop() {
+    struct Msg1<'a>(&'a mut bool);
+    impl Drop for Msg1<'_> {
+        fn drop(&mut self) {
+            if *self.0 && !std::thread::panicking() {
+                panic!("double drop");
+            } else {
+                *self.0 = true;
+            }
+        }
+    }
+
+    struct Msg2<'a>(&'a mut bool);
+    impl Drop for Msg2<'_> {
+        fn drop(&mut self) {
+            if *self.0 {
+                panic!("double drop");
+            } else {
+                *self.0 = true;
+                panic!("first drop");
+            }
+        }
+    }
+
+    // normal
+    let (s, r) = bounded(2);
+    let (mut a, mut b) = (false, false);
+    s.send(Msg1(&mut a)).unwrap();
+    s.send(Msg1(&mut b)).unwrap();
+    drop(s);
+    drop(r);
+    assert!(a);
+    assert!(b);
+
+    // panic on drop
+    let (s, r) = bounded(2);
+    let (mut a, mut b) = (false, false);
+    s.send(Msg2(&mut a)).unwrap();
+    s.send(Msg2(&mut b)).unwrap();
+    drop(s);
+    let res = std::panic::catch_unwind(move || {
+        drop(r);
+    });
+    assert_eq!(
+        *res.unwrap_err().downcast_ref::<&str>().unwrap(),
+        "first drop"
+    );
+    assert!(a);
+    // Elements after the panicked element will leak.
+    assert!(!b);
+}
diff --git a/third_party/rust/crossbeam-channel/tests/select_macro.rs b/third_party/rust/crossbeam-channel/tests/select_macro.rs
--- a/third_party/rust/crossbeam-channel/tests/select_macro.rs
+++ b/third_party/rust/crossbeam-channel/tests/select_macro.rs
@@ -1466,5 +1466,16 @@
             drop(s);
         });
     })
     .unwrap();
 }
+
+#[test]
+fn trailing_comma() {
+    let (s, r) = unbounded::<usize>();
+
+    select! {
+        send(s, 1,) -> _ => {},
+        recv(r,) -> _ => {},
+        default(ms(1000),) => {},
+    }
+}