Auto merge of #115095 - RalfJung:miri, r=RalfJung

update Miri

r? `@ghost`

22 files changed, 326 insertions, 100 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 266f34e69ed..4ebbb16442e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -218,7 +218,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "serde",
- "syn 2.0.27",
+ "syn 2.0.29",
 ]
 
 [[package]]
@@ -500,7 +500,7 @@ dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn 2.0.27",
+ "syn 2.0.29",
 ]
 
 [[package]]
@@ -525,7 +525,7 @@ dependencies = [
  "regex",
  "rustc_tools_util",
  "serde",
- "syn 2.0.27",
+ "syn 2.0.29",
  "tempfile",
  "termize",
  "tester",
@@ -849,7 +849,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "strsim",
- "syn 2.0.27",
+ "syn 2.0.29",
 ]
 
 [[package]]
@@ -860,7 +860,7 @@ checksum = "836a9bbc7ad63342d6d6e7b815ccab164bc77a2d95d84bc3117a8c0d5c98e2d5"
 dependencies = [
  "darling_core",
  "quote",
- "syn 2.0.27",
+ "syn 2.0.29",
 ]
 
 [[package]]
@@ -875,7 +875,7 @@ version = "0.1.73"
 dependencies = [
  "itertools",
  "quote",
- "syn 2.0.27",
+ "syn 2.0.29",
 ]
 
 [[package]]
@@ -911,7 +911,7 @@ dependencies = [
  "darling",
  "proc-macro2",
  "quote",
- "syn 2.0.27",
+ "syn 2.0.29",
 ]
 
 [[package]]
@@ -988,7 +988,7 @@ checksum = "487585f4d0c6655fe74905e2504d8ad6908e4db67f744eb140876906c2f3175d"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.27",
+ "syn 2.0.29",
 ]
 
 [[package]]
@@ -1354,7 +1354,7 @@ checksum = "89ca545a94061b6365f2c7355b4b32bd20df3ff95f02da9329b34ccc3bd6ee72"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.27",
+ "syn 2.0.29",
 ]
 
 [[package]]
@@ -2334,6 +2334,7 @@ dependencies = [
  "rand",
  "regex",
  "rustc_version",
+ "serde",
  "smallvec",
  "ui_test",
 ]
@@ -2503,7 +2504,7 @@ checksum = "a948666b637a0f465e8564c73e89d4dde00d72d4d473cc972f390fc3dcee7d9c"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.27",
+ "syn 2.0.29",
 ]
 
 [[package]]
@@ -2691,7 +2692,7 @@ dependencies = [
  "pest_meta",
  "proc-macro2",
  "quote",
- "syn 2.0.27",
+ "syn 2.0.29",
 ]
 
 [[package]]
@@ -3636,7 +3637,7 @@ dependencies = [
  "fluent-syntax",
  "proc-macro2",
  "quote",
- "syn 2.0.27",
+ "syn 2.0.29",
  "unic-langid",
 ]
 
@@ -3906,7 +3907,7 @@ version = "0.1.0"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.27",
+ "syn 2.0.29",
  "synstructure 0.13.0",
 ]
 
@@ -4514,7 +4515,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "serde",
- "syn 2.0.27",
+ "syn 2.0.29",
 ]
 
 [[package]]
@@ -4666,22 +4667,22 @@ dependencies = [
 
 [[package]]
 name = "serde"
-version = "1.0.164"
+version = "1.0.185"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9e8c8cf938e98f769bc164923b06dce91cea1751522f46f8466461af04c9027d"
+checksum = "be9b6f69f1dfd54c3b568ffa45c310d6973a5e5148fd40cf515acaf38cf5bc31"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.164"
+version = "1.0.185"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d9735b638ccc51c28bf6914d90a2e9725b377144fc612c49a611fddd1b631d68"
+checksum = "dc59dfdcbad1437773485e0367fea4b090a2e0a16d9ffc46af47764536a298ec"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.27",
+ "syn 2.0.29",
 ]
 
 [[package]]
@@ -4962,9 +4963,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "2.0.27"
+version = "2.0.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b60f673f44a8255b9c8c657daf66a596d435f2da81a555b06dc644d080ba45e0"
+checksum = "c324c494eba9d92503e6f1ef2e6df781e78f6a7705a0202d9801b198807d518a"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -4991,7 +4992,7 @@ checksum = "285ba80e733fac80aa4270fbcdf83772a79b80aa35c97075320abfee4a915b06"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.27",
+ "syn 2.0.29",
  "unicode-xid",
 ]
 
@@ -5161,7 +5162,7 @@ checksum = "6bb623b56e39ab7dcd4b1b98bb6c8f8d907ed255b18de254088016b27a8ee19b"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.27",
+ "syn 2.0.29",
 ]
 
 [[package]]
@@ -5382,7 +5383,7 @@ checksum = "5f4f31f56159e98206da9efd823404b79b6ef3143b4a7ab76e67b1751b25a4ab"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.27",
+ "syn 2.0.29",
 ]
 
 [[package]]
@@ -5777,7 +5778,7 @@ dependencies = [
  "once_cell",
  "proc-macro2",
  "quote",
- "syn 2.0.27",
+ "syn 2.0.29",
  "wasm-bindgen-shared",
 ]
 
@@ -5811,7 +5812,7 @@ checksum = "54681b18a46765f095758388f2d0cf16eb8d4169b639ab575a8f5693af210c7b"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.27",
+ "syn 2.0.29",
  "wasm-bindgen-backend",
  "wasm-bindgen-shared",
 ]
diff --git a/src/tools/miri/.github/workflows/ci.yml b/src/tools/miri/.github/workflows/ci.yml
index 8ced9fa86be..5e2abdde6ac 100644
--- a/src/tools/miri/.github/workflows/ci.yml
+++ b/src/tools/miri/.github/workflows/ci.yml
@@ -189,8 +189,6 @@ jobs:
           fetch-depth: 256 # get a bit more of the history
       - name: install josh-proxy
         run: cargo +stable install josh-proxy --git https://github.com/josh-project/josh --tag r22.12.06
-      - name: start josh-proxy
-        run: josh-proxy --local=$HOME/.cache/josh --remote=https://github.com --no-background &
       - name: setup bot git name and email
         run: |
           git config --global user.name 'The Miri Conjob Bot'
diff --git a/src/tools/miri/CONTRIBUTING.md b/src/tools/miri/CONTRIBUTING.md
index b67e7103fd0..4e50b8fae81 100644
--- a/src/tools/miri/CONTRIBUTING.md
+++ b/src/tools/miri/CONTRIBUTING.md
@@ -165,16 +165,17 @@ to `.vscode/settings.json` in your local Miri clone:
 {
     "rust-analyzer.rustc.source": "discover",
     "rust-analyzer.linkedProjects": [
-        "./Cargo.toml",
-        "./cargo-miri/Cargo.toml"
+        "Cargo.toml",
+        "cargo-miri/Cargo.toml",
+        "miri-script/Cargo.toml",
     ],
-    "rust-analyzer.checkOnSave.overrideCommand": [
+    "rust-analyzer.check.overrideCommand": [
         "env",
         "MIRI_AUTO_OPS=no",
         "./miri",
         "cargo",
         "clippy", // make this `check` when working with a locally built rustc
-        "--message-format=json"
+        "--message-format=json",
     ],
     // Contrary to what the name suggests, this also affects proc macros.
     "rust-analyzer.cargo.buildScripts.overrideCommand": [
@@ -230,25 +231,16 @@ You can also directly run Miri on a Rust source file:
 ## Advanced topic: Syncing with the rustc repo
 
 We use the [`josh` proxy](https://github.com/josh-project/josh) to transmit changes between the
-rustc and Miri repositories.
+rustc and Miri repositories. You can install it as follows:
 
 ```sh
 cargo +stable install josh-proxy --git https://github.com/josh-project/josh --tag r22.12.06
-josh-proxy --local=$HOME/.cache/josh --remote=https://github.com --no-background
 ```
 
-This uses a directory `$HOME/.cache/josh` as a cache, to speed up repeated pulling/pushing.
-
-To make josh push via ssh instead of https, you can add the following to your `.gitconfig`:
-
-```toml
-[url "git@github.com:"]
-    pushInsteadOf = https://github.com/
-```
+Josh will automatically be started and stopped by `./miri`.
 
 ### Importing changes from the rustc repo
 
-Josh needs to be running, as described above.
 We assume we start on an up-to-date master branch in the Miri repo.
 
 ```sh
@@ -267,16 +259,14 @@ needed.
 
 ### Exporting changes to the rustc repo
 
-Keep in mind that pushing is the most complicated job that josh has to do --
-pulling just filters the rustc history, but pushing needs to construct a new
-rustc history that would filter to the given Miri history! To avoid problems, it
-is a good idea to always pull immediately before you push. In particular, you
-should never do two josh pushes without an intermediate pull; that can lead to
-duplicated commits.
+Keep in mind that pushing is the most complicated job that josh has to do -- pulling just filters
+the rustc history, but pushing needs to construct a new rustc history that would filter to the given
+Miri history! To avoid problems, it is a good idea to always pull immediately before you push. If
+you are getting strange errors, chances are you are running into [this josh
+bug](https://github.com/josh-project/josh/issues/998). In that case, please get in touch on Zulip.
 
-Josh needs to be running, as described above. We will use the josh proxy to push
-to your fork of rustc. Run the following in the Miri repo, assuming we are on an
-up-to-date master branch:
+We will use the josh proxy to push to your fork of rustc. Run the following in the Miri repo,
+assuming we are on an up-to-date master branch:
 
 ```sh
 # Push the Miri changes to your rustc fork (substitute your github handle for YOUR_NAME).
@@ -286,3 +276,11 @@ up-to-date master branch:
 This will create a new branch called 'miri' in your fork, and the output should
 include a link to create a rustc PR that will integrate those changes into the
 main repository.
+
+If this fails due to authentication problems, it can help to make josh push via ssh instead of
+https. Add the following to your `.gitconfig`:
+
+```toml
+[url "git@github.com:"]
+    pushInsteadOf = https://github.com/
+```
diff --git a/src/tools/miri/Cargo.lock b/src/tools/miri/Cargo.lock
index 4232d7fda78..ca5b6d22515 100644
--- a/src/tools/miri/Cargo.lock
+++ b/src/tools/miri/Cargo.lock
@@ -443,6 +443,7 @@ dependencies = [
  "rand",
  "regex",
  "rustc_version",
+ "serde",
  "smallvec",
  "ui_test",
 ]
@@ -528,18 +529,18 @@ checksum = "5b40af805b3121feab8a3c29f04d8ad262fa8e0561883e7653e024ae4479e6de"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.60"
+version = "1.0.66"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dec2b086b7a862cf4de201096214fa870344cf922b2b30c167badb3af3195406"
+checksum = "18fb31db3f9bddb2ea821cde30a9f70117e3f119938b5ee630b7403aa6e2ead9"
 dependencies = [
  "unicode-ident",
 ]
 
 [[package]]
 name = "quote"
-version = "1.0.26"
+version = "1.0.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4424af4bf778aae2051a77b60283332f386554255d722233d09fbfc7e30da2fc"
+checksum = "5267fca4496028628a95160fc423a33e8b2e6af8a5302579e322e4b520293cae"
 dependencies = [
  "proc-macro2",
 ]
@@ -685,18 +686,18 @@ dependencies = [
 
 [[package]]
 name = "serde"
-version = "1.0.162"
+version = "1.0.185"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "71b2f6e1ab5c2b98c05f0f35b236b22e8df7ead6ffbf51d7808da7f8817e7ab6"
+checksum = "be9b6f69f1dfd54c3b568ffa45c310d6973a5e5148fd40cf515acaf38cf5bc31"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.162"
+version = "1.0.185"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a2a0814352fd64b58489904a44ea8d90cb1a91dcb6b4f5ebabc32c8318e93cb6"
+checksum = "dc59dfdcbad1437773485e0367fea4b090a2e0a16d9ffc46af47764536a298ec"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -737,9 +738,9 @@ checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
 
 [[package]]
 name = "syn"
-version = "2.0.15"
+version = "2.0.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a34fcf3e8b60f57e6a14301a2e916d323af98b0ea63c599441eec8558660c822"
+checksum = "c324c494eba9d92503e6f1ef2e6df781e78f6a7705a0202d9801b198807d518a"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/src/tools/miri/Cargo.toml b/src/tools/miri/Cargo.toml
index a625e1696e1..67a2aeefa02 100644
--- a/src/tools/miri/Cargo.toml
+++ b/src/tools/miri/Cargo.toml
@@ -41,6 +41,8 @@ rustc_version = "0.4"
 # Features chosen to match those required by env_logger, to avoid rebuilds
 regex = { version = "1.5.5", default-features = false, features = ["perf", "std"] }
 lazy_static = "1.4.0"
+# Require a version of serde without intransparent unreproducible binary blobs.
+serde = { version = "1.0.185", features = ["derive"] }
 
 [package.metadata.rust-analyzer]
 # This crate uses #[feature(rustc_private)].
diff --git a/src/tools/miri/README.md b/src/tools/miri/README.md
index 4483ae242d5..06fe668354a 100644
--- a/src/tools/miri/README.md
+++ b/src/tools/miri/README.md
@@ -458,8 +458,8 @@ Some native rustc `-Z` flags are also very relevant for Miri:
 Moreover, Miri recognizes some environment variables:
 
 * `MIRI_AUTO_OPS` indicates whether the automatic execution of rustfmt, clippy and toolchain setup
-  should be skipped. If it is set to any value, they are skipped. This is used for avoiding infinite
-  recursion in `./miri` and to allow automated IDE actions to avoid the auto ops.
+  should be skipped. If it is set to `no`, they are skipped. This is used to allow automated IDE
+  actions to avoid the auto ops.
 * `MIRI_LOG`, `MIRI_BACKTRACE` control logging and backtrace printing during
   Miri executions, also [see "Testing the Miri driver" in `CONTRIBUTING.md`][testing-miri].
 * `MIRIFLAGS` (recognized by `cargo miri` and the test suite) defines extra
diff --git a/src/tools/miri/cargo-miri/Cargo.lock b/src/tools/miri/cargo-miri/Cargo.lock
index 47fdc65fa96..1f3a33270e1 100644
--- a/src/tools/miri/cargo-miri/Cargo.lock
+++ b/src/tools/miri/cargo-miri/Cargo.lock
@@ -178,18 +178,18 @@ checksum = "ece97ea872ece730aed82664c424eb4c8291e1ff2480247ccf7409044bc6479f"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.60"
+version = "1.0.66"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dec2b086b7a862cf4de201096214fa870344cf922b2b30c167badb3af3195406"
+checksum = "18fb31db3f9bddb2ea821cde30a9f70117e3f119938b5ee630b7403aa6e2ead9"
 dependencies = [
  "unicode-ident",
 ]
 
 [[package]]
 name = "quote"
-version = "1.0.26"
+version = "1.0.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4424af4bf778aae2051a77b60283332f386554255d722233d09fbfc7e30da2fc"
+checksum = "5267fca4496028628a95160fc423a33e8b2e6af8a5302579e322e4b520293cae"
 dependencies = [
  "proc-macro2",
 ]
@@ -280,18 +280,18 @@ dependencies = [
 
 [[package]]
 name = "serde"
-version = "1.0.162"
+version = "1.0.185"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "71b2f6e1ab5c2b98c05f0f35b236b22e8df7ead6ffbf51d7808da7f8817e7ab6"
+checksum = "be9b6f69f1dfd54c3b568ffa45c310d6973a5e5148fd40cf515acaf38cf5bc31"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.162"
+version = "1.0.185"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a2a0814352fd64b58489904a44ea8d90cb1a91dcb6b4f5ebabc32c8318e93cb6"
+checksum = "dc59dfdcbad1437773485e0367fea4b090a2e0a16d9ffc46af47764536a298ec"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -311,9 +311,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "2.0.15"
+version = "2.0.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a34fcf3e8b60f57e6a14301a2e916d323af98b0ea63c599441eec8558660c822"
+checksum = "c324c494eba9d92503e6f1ef2e6df781e78f6a7705a0202d9801b198807d518a"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/src/tools/miri/cargo-miri/Cargo.toml b/src/tools/miri/cargo-miri/Cargo.toml
index cfa5ac5281d..e118d12897a 100644
--- a/src/tools/miri/cargo-miri/Cargo.toml
+++ b/src/tools/miri/cargo-miri/Cargo.toml
@@ -22,7 +22,8 @@ rustc-build-sysroot = "0.4.1"
 
 # Enable some feature flags that dev-dependencies need but dependencies
 # do not.  This makes `./miri install` after `./miri build` faster.
-serde = { version = "*", features = ["derive"] }
+# Require a version of serde without intransparent unreproducible binary blobs.
+serde = { version = "1.0.185", features = ["derive"] }
 
 [build-dependencies]
 rustc_tools_util = "0.3"
diff --git a/src/tools/miri/ci.sh b/src/tools/miri/ci.sh
index a8aae524e71..3146ef41a3b 100755
--- a/src/tools/miri/ci.sh
+++ b/src/tools/miri/ci.sh
@@ -52,7 +52,7 @@ function run_tests {
 
     # Also run some many-seeds tests. 64 seeds means this takes around a minute per test.
     for FILE in tests/many-seeds/*.rs; do
-      MIRI_SEEDS=64 CARGO_EXTRA_FLAGS="$CARGO_EXTRA_FLAGS -q" ./miri many-seeds ./miri run "$FILE"
+      MIRI_SEEDS=64 ./miri many-seeds ./miri run "$FILE"
     done
 
     # Check that the benchmarks build and run, but without actually benchmarking.
diff --git a/src/tools/miri/miri b/src/tools/miri/miri
index c816a4bb06b..938df9799da 100755
--- a/src/tools/miri/miri
+++ b/src/tools/miri/miri
@@ -2,5 +2,5 @@
 set -e
 # Instead of doing just `cargo run --manifest-path .. $@`, we invoke miri-script binary directly. Invoking `cargo run` goes through
 # rustup (that sets it's own environmental variables), which is undesirable.
-cargo build -q --manifest-path "$(dirname "$0")"/miri-script/Cargo.toml
+cargo build $CARGO_EXTRA_FLAGS -q --manifest-path "$(dirname "$0")"/miri-script/Cargo.toml
 "$(dirname "$0")"/miri-script/target/debug/miri-script "$@"
diff --git a/src/tools/miri/miri-script/Cargo.lock b/src/tools/miri/miri-script/Cargo.lock
index cf6062d7d7f..1a22596b774 100644
--- a/src/tools/miri/miri-script/Cargo.lock
+++ b/src/tools/miri/miri-script/Cargo.lock
@@ -9,6 +9,38 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9c7d0618f0e0b7e8ff11427422b64564d5fb0be1940354bfe2e0529b18a9d9b8"
 
 [[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "directories"
+version = "4.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f51c5d4ddabd36886dd3e1438cb358cdcb0d7c499cb99cb4ac2e38e18b5cb210"
+dependencies = [
+ "dirs-sys",
+]
+
+[[package]]
+name = "dirs-sys"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b1d1d91c932ef41c0f2663aa8b0ca0342d444d842c06914aa0a7e352d0bada6"
+dependencies = [
+ "libc",
+ "redox_users",
+ "winapi",
+]
+
+[[package]]
 name = "dunce"
 version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -21,6 +53,17 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7fcaabb2fef8c910e7f4c7ce9f67a1283a1715879a7c230ca9d6d1ae31f16d91"
 
 [[package]]
+name = "getrandom"
+version = "0.2.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be4136b2a15dd319360be1c07d9933517ccf0be8f16bf62a3bee4f0d618df427"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
+[[package]]
 name = "itertools"
 version = "0.10.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -40,6 +83,7 @@ name = "miri-script"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "directories",
  "dunce",
  "itertools",
  "path_macro",
@@ -63,6 +107,44 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a6e819bbd49d5939f682638fa54826bf1650abddcd65d000923de8ad63cc7d15"
 
 [[package]]
+name = "proc-macro2"
+version = "1.0.66"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "18fb31db3f9bddb2ea821cde30a9f70117e3f119938b5ee630b7403aa6e2ead9"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5267fca4496028628a95160fc423a33e8b2e6af8a5302579e322e4b520293cae"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "redox_syscall"
+version = "0.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fb5a58c1855b4b6819d59012155603f0b22ad30cad752600aadfcb695265519a"
+dependencies = [
+ "bitflags",
+]
+
+[[package]]
+name = "redox_users"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b033d837a7cf162d7993aded9304e30a83213c648b6e389db233191f891e5c2b"
+dependencies = [
+ "getrandom",
+ "redox_syscall",
+ "thiserror",
+]
+
+[[package]]
 name = "rustc_version"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -93,6 +175,43 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "24188a676b6ae68c3b2cb3a01be17fbf7240ce009799bb56d5b1409051e78fde"
 
 [[package]]
+name = "syn"
+version = "2.0.29"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c324c494eba9d92503e6f1ef2e6df781e78f6a7705a0202d9801b198807d518a"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "thiserror"
+version = "1.0.47"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "97a802ec30afc17eee47b2855fc72e0c4cd62be9b4efe6591edde0ec5bd68d8f"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "1.0.47"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6bb623b56e39ab7dcd4b1b98bb6c8f8d907ed255b18de254088016b27a8ee19b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "301abaae475aa91687eb82514b328ab47a211a533026cb25fc3e519b86adfc3c"
+
+[[package]]
 name = "walkdir"
 version = "2.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -103,6 +222,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "wasi"
+version = "0.11.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
+
+[[package]]
 name = "which"
 version = "4.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
diff --git a/src/tools/miri/miri-script/Cargo.toml b/src/tools/miri/miri-script/Cargo.toml
index c0414a2fe37..d805a94c8f5 100644
--- a/src/tools/miri/miri-script/Cargo.toml
+++ b/src/tools/miri/miri-script/Cargo.toml
@@ -20,3 +20,4 @@ anyhow = "1.0"
 xshell = "0.2"
 rustc_version = "0.4"
 dunce = "1.0.4"
+directories = "4"
diff --git a/src/tools/miri/miri-script/src/commands.rs b/src/tools/miri/miri-script/src/commands.rs
index ed78f80c023..2948219ad89 100644
--- a/src/tools/miri/miri-script/src/commands.rs
+++ b/src/tools/miri/miri-script/src/commands.rs
@@ -2,6 +2,9 @@ use std::env;
 use std::ffi::OsString;
 use std::io::Write;
 use std::ops::Not;
+use std::process;
+use std::thread;
+use std::time;
 
 use anyhow::{anyhow, bail, Context, Result};
 use path_macro::path;
@@ -14,6 +17,7 @@ use crate::Command;
 /// Used for rustc syncs.
 const JOSH_FILTER: &str =
     ":rev(75dd959a3a40eb5b4574f8d2e23aa6efbeb33573:prefix=src/tools/miri):/src/tools/miri";
+const JOSH_PORT: &str = "42042";
 
 impl MiriEnv {
     fn build_miri_sysroot(&mut self, quiet: bool) -> Result<()> {
@@ -57,6 +61,10 @@ impl MiriEnv {
 
 impl Command {
     fn auto_actions() -> Result<()> {
+        if env::var_os("MIRI_AUTO_OPS").is_some_and(|x| x == "no") {
+            return Ok(());
+        }
+
         let miri_dir = miri_dir()?;
         let auto_everything = path!(miri_dir / ".auto-everything").exists();
         let auto_toolchain = auto_everything || path!(miri_dir / ".auto-toolchain").exists();
@@ -77,7 +85,57 @@ impl Command {
         Ok(())
     }
 
+    fn start_josh() -> Result<impl Drop> {
+        // Determine cache directory.
+        let local_dir = {
+            let user_dirs =
+                directories::ProjectDirs::from("org", "rust-lang", "miri-josh").unwrap();
+            user_dirs.cache_dir().to_owned()
+        };
+
+        // Start josh, silencing its output.
+        let mut cmd = process::Command::new("josh-proxy");
+        cmd.arg("--local").arg(local_dir);
+        cmd.arg("--remote").arg("https://github.com");
+        cmd.arg("--port").arg(JOSH_PORT);
+        cmd.arg("--no-background");
+        cmd.stdout(process::Stdio::null());
+        cmd.stderr(process::Stdio::null());
+        let josh = cmd.spawn().context("failed to start josh-proxy, make sure it is installed")?;
+        // Give it some time so hopefully the port is open. (10ms was not enough.)
+        thread::sleep(time::Duration::from_millis(100));
+
+        // Create a wrapper that stops it on drop.
+        struct Josh(process::Child);
+        impl Drop for Josh {
+            fn drop(&mut self) {
+                #[cfg(unix)]
+                {
+                    // Try to gracefully shut it down.
+                    process::Command::new("kill")
+                        .args(["-s", "INT", &self.0.id().to_string()])
+                        .output()
+                        .expect("failed to SIGINT josh-proxy");
+                    // Sadly there is no "wait with timeout"... so we just give it some time to finish.
+                    thread::sleep(time::Duration::from_millis(100));
+                    // Now hopefully it is gone.
+                    if self.0.try_wait().expect("failed to wait for josh-proxy").is_some() {
+                        return;
+                    }
+                }
+                // If that didn't work (or we're not on Unix), kill it hard.
+                eprintln!(
+                    "I have to kill josh-proxy the hard way, let's hope this does not break anything."
+                );
+                self.0.kill().expect("failed to SIGKILL josh-proxy");
+            }
+        }
+
+        Ok(Josh(josh))
+    }
+
     pub fn exec(self) -> Result<()> {
+        // First, and crucially only once, run the auto-actions -- but not for all commands.
         match &self {
             Command::Install { .. }
             | Command::Build { .. }
@@ -89,10 +147,11 @@ impl Command {
             | Command::Cargo { .. } => Self::auto_actions()?,
             | Command::ManySeeds { .. }
             | Command::Toolchain { .. }
-            | Command::RustcPull { .. }
             | Command::Bench { .. }
+            | Command::RustcPull { .. }
             | Command::RustcPush { .. } => {}
         }
+        // Then run the actual command.
         match self {
             Command::Install { flags } => Self::install(flags),
             Command::Build { flags } => Self::build(flags),
@@ -168,6 +227,8 @@ impl Command {
         if cmd!(sh, "git status --untracked-files=no --porcelain").read()?.is_empty().not() {
             bail!("working directory must be clean before running `./miri rustc-pull`");
         }
+        // Make sure josh is running.
+        let josh = Self::start_josh()?;
 
         // Update rust-version file. As a separate commit, since making it part of
         // the merge has confused the heck out of josh in the past.
@@ -180,7 +241,7 @@ impl Command {
             .context("FAILED to commit rust-version file, something went wrong")?;
 
         // Fetch given rustc commit.
-        cmd!(sh, "git fetch http://localhost:8000/rust-lang/rust.git@{commit}{JOSH_FILTER}.git")
+        cmd!(sh, "git fetch http://localhost:{JOSH_PORT}/rust-lang/rust.git@{commit}{JOSH_FILTER}.git")
             .run()
             .map_err(|e| {
                 // Try to un-do the previous `git commit`, to leave the repo in the state we found it it.
@@ -196,6 +257,8 @@ impl Command {
         cmd!(sh, "git merge FETCH_HEAD --no-verify --no-ff -m {MERGE_COMMIT_MESSAGE}")
             .run()
             .context("FAILED to merge new commits, something went wrong")?;
+
+        drop(josh);
         Ok(())
     }
 
@@ -207,6 +270,8 @@ impl Command {
         if cmd!(sh, "git status --untracked-files=no --porcelain").read()?.is_empty().not() {
             bail!("working directory must be clean before running `./miri rustc-push`");
         }
+        // Make sure josh is running.
+        let josh = Self::start_josh()?;
 
         // Find a repo we can do our preparation in.
         if let Ok(rustc_git) = env::var("RUSTC_GIT") {
@@ -243,6 +308,8 @@ impl Command {
         }
         cmd!(sh, "git fetch https://github.com/rust-lang/rust {base}").run()?;
         cmd!(sh, "git push https://github.com/{github_user}/rust {base}:refs/heads/{branch}")
+            .ignore_stdout()
+            .ignore_stderr() // silence the "create GitHub PR" message
             .run()?;
         println!();
 
@@ -251,7 +318,7 @@ impl Command {
         println!("Pushing miri changes...");
         cmd!(
             sh,
-            "git push http://localhost:8000/{github_user}/rust.git{JOSH_FILTER}.git HEAD:{branch}"
+            "git push http://localhost:{JOSH_PORT}/{github_user}/rust.git{JOSH_FILTER}.git HEAD:{branch}"
         )
         .run()?;
         println!();
@@ -259,7 +326,7 @@ impl Command {
         // Do a round-trip check to make sure the push worked as expected.
         cmd!(
             sh,
-            "git fetch http://localhost:8000/{github_user}/rust.git{JOSH_FILTER}.git {branch}"
+            "git fetch http://localhost:{JOSH_PORT}/{github_user}/rust.git{JOSH_FILTER}.git {branch}"
         )
         .ignore_stderr()
         .read()?;
@@ -272,6 +339,8 @@ impl Command {
             "Confirmed that the push round-trips back to Miri properly. Please create a rustc PR:"
         );
         println!("    https://github.com/{github_user}/rust/pull/new/{branch}");
+
+        drop(josh);
         Ok(())
     }
 
@@ -289,6 +358,7 @@ impl Command {
             bail!("expected many-seeds command to be non-empty");
         };
         let sh = Shell::new()?;
+        sh.set_var("MIRI_AUTO_OPS", "no"); // just in case we get recursively invoked
         for seed in seed_start..seed_end {
             println!("Trying seed: {seed}");
             let mut miriflags = env::var_os("MIRIFLAGS").unwrap_or_default();
@@ -313,6 +383,8 @@ impl Command {
         let Some((program_name, args)) = hyperfine.split_first() else {
             bail!("expected HYPERFINE environment variable to be non-empty");
         };
+        // Extra flags to pass to cargo.
+        let cargo_extra_flags = std::env::var("CARGO_EXTRA_FLAGS").unwrap_or_default();
         // Make sure we have an up-to-date Miri installed and selected the right toolchain.
         Self::install(vec![])?;
 
@@ -335,7 +407,7 @@ impl Command {
             // That seems to make Windows CI happy.
             cmd!(
                 sh,
-                "{program_name} {args...} 'cargo miri run --manifest-path \"'{current_bench}'\"'"
+                "{program_name} {args...} 'cargo miri run '{cargo_extra_flags}' --manifest-path \"'{current_bench}'\"'"
             )
             .run()?;
         }
diff --git a/src/tools/miri/miri-script/src/main.rs b/src/tools/miri/miri-script/src/main.rs
index 849a9168028..41b82cfc472 100644
--- a/src/tools/miri/miri-script/src/main.rs
+++ b/src/tools/miri/miri-script/src/main.rs
@@ -1,3 +1,5 @@
+#![allow(clippy::needless_question_mark)]
+
 mod commands;
 mod util;
 
diff --git a/src/tools/miri/rust-version b/src/tools/miri/rust-version
index 30123b92f6c..d96e7040aaf 100644
--- a/src/tools/miri/rust-version
+++ b/src/tools/miri/rust-version
@@ -1 +1 @@
-656ee47db32e882fb02913f6204e09cc7a41a50e
+c40cfcf0494ff7506e753e750adb00eeea839f9c
diff --git a/src/tools/miri/src/borrow_tracker/tree_borrows/perms.rs b/src/tools/miri/src/borrow_tracker/tree_borrows/perms.rs
index 0ce29ac5437..dab216bc5b1 100644
--- a/src/tools/miri/src/borrow_tracker/tree_borrows/perms.rs
+++ b/src/tools/miri/src/borrow_tracker/tree_borrows/perms.rs
@@ -68,17 +68,31 @@ mod transition {
     fn foreign_read(state: PermissionPriv, protected: bool) -> Option<PermissionPriv> {
         use Option::*;
         Some(match state {
+            // Non-writeable states just ignore foreign reads.
+            non_writeable @ (Frozen | Disabled) => non_writeable,
+            // Writeable states are more tricky, and depend on whether things are protected.
             // The inner data `ty_is_freeze` of `Reserved` is always irrelevant for Read
             // accesses, since the data is not being mutated. Hence the `{ .. }`
-            res @ Reserved { .. } if !protected => res,
-            Reserved { .. } => Frozen, // protected reserved
+            res @ Reserved { .. } =>
+                if protected {
+                    // Someone else read, make sure we won't write.
+                    // We could make this `Disabled` but it doesn't look like we get anything out of that extra UB.
+                    Frozen
+                } else {
+                    // Before activation and without protectors, foreign reads are fine.
+                    // That's the entire point of 2-phase borrows.
+                    res
+                },
             Active =>
                 if protected {
+                    // We wrote, someone else reads -- that's bad.
+                    // (If this is initialized, this move-to-protected will mean insta-UB.)
                     Disabled
                 } else {
+                    // We don't want to disable here to allow read-read reordering: it is crucial
+                    // that the foreign read does not invalidate future reads through this tag.
                     Frozen
                 },
-            non_writeable @ (Frozen | Disabled) => non_writeable,
         })
     }
 
diff --git a/src/tools/miri/src/lib.rs b/src/tools/miri/src/lib.rs
index d57da574315..03dd9037808 100644
--- a/src/tools/miri/src/lib.rs
+++ b/src/tools/miri/src/lib.rs
@@ -32,6 +32,7 @@
     clippy::needless_return,
     clippy::bool_to_int_with_if,
     clippy::box_default,
+    clippy::needless_question_mark,
     // We are not implementing queries here so it's fine
     rustc::potential_query_instability
 )]
diff --git a/src/tools/miri/src/shims/intrinsics/mod.rs b/src/tools/miri/src/shims/intrinsics/mod.rs
index ea6ea5a8474..8a84b4f51b7 100644
--- a/src/tools/miri/src/shims/intrinsics/mod.rs
+++ b/src/tools/miri/src/shims/intrinsics/mod.rs
@@ -44,7 +44,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
                     "the program aborted execution".to_owned()
                 ))
             }
-            _ => {},
+            _ => {}
         }
 
         // All remaining supported intrinsics have a return place.
diff --git a/src/tools/miri/test-cargo-miri/Cargo.lock b/src/tools/miri/test-cargo-miri/Cargo.lock
index cf5ec2aa883..d5e57a66a8d 100644
--- a/src/tools/miri/test-cargo-miri/Cargo.lock
+++ b/src/tools/miri/test-cargo-miri/Cargo.lock
@@ -83,27 +83,27 @@ version = "0.1.0"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.60"
+version = "1.0.66"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dec2b086b7a862cf4de201096214fa870344cf922b2b30c167badb3af3195406"
+checksum = "18fb31db3f9bddb2ea821cde30a9f70117e3f119938b5ee630b7403aa6e2ead9"
 dependencies = [
  "unicode-ident",
 ]
 
 [[package]]
 name = "quote"
-version = "1.0.23"
+version = "1.0.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8856d8364d252a14d474036ea1358d63c9e6965c8e5c1885c18f73d70bff9c7b"
+checksum = "5267fca4496028628a95160fc423a33e8b2e6af8a5302579e322e4b520293cae"
 dependencies = [
  "proc-macro2",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.152"
+version = "1.0.185"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "af487d118eecd09402d70a5d72551860e788df87b464af30e5ea6a38c75c541e"
+checksum = "dc59dfdcbad1437773485e0367fea4b090a2e0a16d9ffc46af47764536a298ec"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -119,9 +119,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.107"
+version = "2.0.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1f4064b5b16e03ae50984a5a8ed5d4f8803e6bc1fd170a3cda91a1be4b18e3f5"
+checksum = "c324c494eba9d92503e6f1ef2e6df781e78f6a7705a0202d9801b198807d518a"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/src/tools/miri/test-cargo-miri/Cargo.toml b/src/tools/miri/test-cargo-miri/Cargo.toml
index 37c996de662..1688096fd9a 100644
--- a/src/tools/miri/test-cargo-miri/Cargo.toml
+++ b/src/tools/miri/test-cargo-miri/Cargo.toml
@@ -20,7 +20,8 @@ issue_rust_86261 = { path = "issue-rust-86261" }
 
 [dev-dependencies]
 byteorder_2 = { package = "byteorder", version = "0.5" } # to test dev-dependencies behave as expected, with renaming
-serde_derive = "1.0" # not actually used, but exercises some unique code path (`--extern` .so file)
+# Not actually used, but exercises some unique code path (`--extern` .so file).
+serde_derive = "1.0.185"
 
 [build-dependencies]
 autocfg = "1"
diff --git a/src/tools/miri/test-cargo-miri/run-test.py b/src/tools/miri/test-cargo-miri/run-test.py
index ca2f69fc8cf..db4341169ea 100755
--- a/src/tools/miri/test-cargo-miri/run-test.py
+++ b/src/tools/miri/test-cargo-miri/run-test.py
@@ -15,12 +15,14 @@ CGREEN  = '\33[32m'
 CBOLD   = '\33[1m'
 CEND    = '\33[0m'
 
+CARGO_EXTRA_FLAGS = os.environ.get("CARGO_EXTRA_FLAGS", "").split()
+
 def fail(msg):
     print("\nTEST FAIL: {}".format(msg))
     sys.exit(1)
 
 def cargo_miri(cmd, quiet = True):
-    args = ["cargo", "miri", cmd]
+    args = ["cargo", "miri", cmd] + CARGO_EXTRA_FLAGS
     if quiet:
         args += ["-q"]
     if 'MIRI_TEST_TARGET' in os.environ:
diff --git a/src/tools/miri/tests/compiletest.rs b/src/tools/miri/tests/compiletest.rs
index 8b97c8bb83c..78dd3df01ec 100644
--- a/src/tools/miri/tests/compiletest.rs
+++ b/src/tools/miri/tests/compiletest.rs
@@ -16,6 +16,11 @@ fn get_host() -> String {
         .host
 }
 
+pub fn flagsplit(flags: &str) -> Vec<String> {
+    // This code is taken from `RUSTFLAGS` handling in cargo.
+    flags.split(' ').map(str::trim).filter(|s| !s.is_empty()).map(str::to_string).collect()
+}
+
 // Build the shared object file for testing external C function calls.
 fn build_so_for_c_ffi_tests() -> PathBuf {
     let cc = option_env!("CC").unwrap_or("cc");
@@ -100,14 +105,16 @@ fn test_config(target: &str, path: &str, mode: Mode, with_dependencies: bool) ->
     if with_dependencies && use_std {
         config.dependencies_crate_manifest_path =
             Some(Path::new("test_dependencies").join("Cargo.toml"));
-        config.dependency_builder.args = vec![
-            "run".into(),
+        let mut builder_args = vec!["run".into()];
+        builder_args.extend(flagsplit(&env::var("CARGO_EXTRA_FLAGS").unwrap_or_default()));
+        builder_args.extend([
             "--manifest-path".into(),
             "cargo-miri/Cargo.toml".into(),
             "--".into(),
             "miri".into(),
             "run".into(), // There is no `cargo miri build` so we just use `cargo miri run`.
-        ];
+        ]);
+        config.dependency_builder.args = builder_args.into_iter().map(Into::into).collect();
     }
     config
 }