feat(crashtracker): add opt-in signal-safe collector

.github/workflows/crashtracker-signal-safe.yml

@@ -0,0 +1,64 @@
+# Copyright 2026-Present Datadog, Inc. https://www.datadoghq.com/
+# SPDX-License-Identifier: Apache-2.0
+
+name: Crashtracker signal-safe
+
+on:
+  pull_request:
+    paths:
+      - "libdd-crashtracker/**"
+      - "libdd-crashtracker-ffi/**"
+      - "libdd-profiling-ffi/**"
+      - "builder/**"
+      - "tools/check_signal_safe_symbols.sh"
+      - ".github/workflows/crashtracker-signal-safe.yml"
+      - "Cargo.toml"
+      - "Cargo.lock"
+  push:
+    branches:
+      - main
+
+jobs:
+  signal-safe:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
+      - name: Install Rust toolchain
+        run: |
+          rustup set profile minimal
+          rustup toolchain install stable
+          rustup component add clippy --toolchain stable
+          rustup target add aarch64-unknown-linux-gnu
+      - name: Install cargo nextest
+        uses: taiki-e/install-action@2c41309d51ede152b6f2ee6bf3b71e6dc9a8b7df # 2.49.27
+        with:
+          tool: nextest@0.9.96
+      - name: Check signal-safe collector
+        run: cargo check -p libdd-crashtracker --no-default-features --features collector_signal-safe
+      - name: Check aarch64 signal-safe collector
+        run: cargo check -p libdd-crashtracker --target aarch64-unknown-linux-gnu --no-default-features --features collector_signal-safe
+      - name: Clippy signal-safe collector
+        run: cargo +stable clippy -p libdd-crashtracker --no-default-features --features collector_signal-safe --all-targets -- -D warnings
+      - name: Test signal-safe collector
+        run: cargo nextest run -p libdd-crashtracker --no-default-features --features collector_signal-safe --no-fail-fast
+      - name: Test signal-safe receiver compatibility
+        run: cargo nextest run -p libdd-crashtracker --features "collector_signal-safe,receiver" --no-fail-fast
+      - name: Symbol guard
+        run: bash tools/check_signal_safe_symbols.sh
+
+  signal-safe-macos:
+    runs-on: macos-latest
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
+      - name: Install Rust toolchain
+        run: |
+          rustup set profile minimal
+          rustup toolchain install stable
+      - name: Install cargo nextest
+        uses: taiki-e/install-action@2c41309d51ede152b6f2ee6bf3b71e6dc9a8b7df # 2.49.27
+        with:
+          tool: nextest@0.9.96
+      - name: Test signal-safe collector fallback paths
+        run: cargo nextest run -p libdd-crashtracker --no-default-features --features collector_signal-safe --no-fail-fast

AGENTS.md

@@ -46,7 +46,7 @@ Iterate fastest with `cargo check -p <crate>` while editing; the full validation
 
 ### Per-crate test notes
 
-- **crashtracker**: needs `--features libdd-crashtracker/generate-unit-test-files` for unit tests.
+- **crashtracker**: needs `--features libdd-crashtracker/generate-unit-test-files` for its unit tests. For the signal-safe collector, validate with `cargo check -p libdd-crashtracker --no-default-features --features collector_signal-safe`, `cargo +stable clippy -p libdd-crashtracker --no-default-features --features collector_signal-safe --all-targets -- -D warnings`, `cargo nextest run -p libdd-crashtracker --no-default-features --features collector_signal-safe --no-fail-fast`, `cargo nextest run -p libdd-crashtracker --features "collector_signal-safe,receiver" --no-fail-fast`, and `bash tools/check_signal_safe_symbols.sh`.
 - **http-client**: ships two alternative backend features (`reqwest-backend` is the default, `hyper-backend` is the alternative). Cargo does not enforce exclusivity, but each backend must be exercised independently when this crate is touched:
   ```bash
   # Default (reqwest) backend — covered by the workspace test run

LICENSE-3rdparty.csv

@@ -167,10 +167,12 @@ gloo-timers,https://github.com/rustwasm/gloo/tree/master/crates/timers,MIT OR Ap
 h2,https://github.com/hyperium/h2,MIT,"Carl Lerche <me@carllerche.com>, Sean McArthur <sean@seanmonstar.com>"
 half,https://github.com/starkat99/half-rs,MIT OR Apache-2.0,Kathryn Long <squeeself@gmail.com>
 halfbrown,https://github.com/Licenser/halfbrown,Apache-2.0 OR MIT,Heinz N. Gies <heinz@licenser.net>
+hash32,https://github.com/japaric/hash32,MIT OR Apache-2.0,Jorge Aparicio <jorge@japaric.io>
 hashbrown,https://github.com/rust-lang/hashbrown,MIT OR Apache-2.0,Amanieu d'Antras <amanieu@gmail.com>
 hdrhistogram,https://github.com/HdrHistogram/HdrHistogram_rust,MIT OR Apache-2.0,"Jon Gjengset <jon@thesquareplanet.com>, Marshall Pierce <marshall@mpierce.org>"
 headers,https://github.com/hyperium/headers,MIT,Sean McArthur <sean@seanmonstar.com>
 headers-core,https://github.com/hyperium/headers,MIT,Sean McArthur <sean@seanmonstar.com>
+heapless,https://github.com/rust-embedded/heapless,MIT OR Apache-2.0,"Jorge Aparicio <jorge@japaric.io>, Per Lindgren <per.lindgren@ltu.se>, Emil Fresk <emil.fresk@gmail.com>"
 heck,https://github.com/withoutboats/heck,MIT OR Apache-2.0,The heck Authors
 heck,https://github.com/withoutboats/heck,MIT OR Apache-2.0,Without Boats <woboats@gmail.com>
 hermit-abi,https://github.com/hermit-os/hermit-rs,MIT OR Apache-2.0,Stefan Lankes
@@ -255,7 +257,6 @@ nom,https://github.com/Geal/nom,MIT,contact@geoffroycouprie.com
 ntapi,https://github.com/MSxDOS/ntapi,Apache-2.0 OR MIT,MSxDOS <melcodos@gmail.com>
 nu-ansi-term,https://github.com/nushell/nu-ansi-term,MIT,"ogham@bsago.me, Ryan Scheel (Havvy) <ryan.havvy@gmail.com>, Josh Triplett <josh@joshtriplett.org>, The Nushell Project Developers"
 num-conv,https://github.com/jhpratt/num-conv,MIT OR Apache-2.0,Jacob Pratt <jacob@jhpratt.dev>
-num-derive,https://github.com/rust-num/num-derive,MIT OR Apache-2.0,The Rust Project Developers
 num-traits,https://github.com/rust-num/num-traits,MIT OR Apache-2.0,The Rust Project Developers
 objc2,https://github.com/madsmtm/objc2,MIT,Mads Marquart <mads@marquart.dk>
 objc2-cloud-kit,https://github.com/madsmtm/objc2,Zlib OR Apache-2.0 OR MIT,The objc2-cloud-kit Authors
@@ -375,6 +376,7 @@ semver,https://github.com/dtolnay/semver,MIT OR Apache-2.0,David Tolnay <dtolnay
 sendfd,https://github.com/standard-ai/sendfd,Apache-2.0 OR BSD-3-Clause,"Simonas Kazlauskas <simonas@standard.ai>, Bernardo Meurer <bernardo@standard.ai>, Léo Gaspard <leo@standard.ai>"
 serde,https://github.com/serde-rs/serde,MIT OR Apache-2.0,"Erick Tryzelaar <erick.tryzelaar@gmail.com>, David Tolnay <dtolnay@gmail.com>"
 serde-bool,https://github.com/x52dev/serde-utils,MIT OR Apache-2.0,Rob Ede <robjtede@icloud.com>
+serde-json-core,https://github.com/rust-embedded-community/serde-json-core,MIT OR Apache-2.0,"Jorge Aparicio <jorge@japaric.io>, Ryan Summers <ryan.summers@vertigo-designs.com>, Robert Jördens <rj@quartiq.de>, Mathias Koch <mk@factbird.com>"
 serde-transcode,https://github.com/sfackler/serde-transcode,MIT OR Apache-2.0,Steven Fackler <sfackler@palantir.com>
 serde_bytes,https://github.com/serde-rs/bytes,MIT OR Apache-2.0,David Tolnay <dtolnay@gmail.com>
 serde_core,https://github.com/serde-rs/serde,MIT OR Apache-2.0,"Erick Tryzelaar <erick.tryzelaar@gmail.com>, David Tolnay <dtolnay@gmail.com>"

docs/RFCs/artifacts/crashtracker-unified-runtime-stack-schema-v1_8.json

@@ -302,14 +302,22 @@
       }
     },
     "SiCodes": {
-      "description": "See https://man7.org/linux/man-pages/man2/sigaction.2.html MUST REMAIN IN SYNC WITH THE ENUM IN emit_sigcodes.c",
+      "description": "See https://man7.org/linux/man-pages/man2/sigaction.2.html",
       "type": "string",
       "enum": [
         "BUS_ADRALN",
         "BUS_ADRERR",
         "BUS_MCEERR_AO",
         "BUS_MCEERR_AR",
         "BUS_OBJERR",
+        "FPE_FLTDIV",
+        "FPE_FLTINV",
+        "FPE_FLTOVF",
+        "FPE_FLTRES",
+        "FPE_FLTSUB",
+        "FPE_FLTUND",
+        "FPE_INTDIV",
+        "FPE_INTOVF",
         "ILL_BADSTK",
         "ILL_COPROC",
         "ILL_ILLADR",

examples/ffi/crashtracking.c

@@ -115,10 +115,16 @@ int main(int argc, char **argv) {
   // Test raising SEGV explicitly, to ensure chaining works
   // properly in this case
   raise(SIGSEGV);
+#elif defined(__APPLE__) && defined(__aarch64__)
+  // Optimized arm64 macOS builds may lower the undefined null write below to
+  // a trap instruction, which terminates with SIGTRAP instead of SIGSEGV.
+  raise(SIGSEGV);
 #endif
 
+#if !defined(EXPLICIT_RAISE_SEGV) && !(defined(__APPLE__) && defined(__aarch64__))
   char *bug = NULL;
   *bug = 42;
+#endif
 
   // The crash handler should intercept the SIGSEGV, invoke the receiver,
   // and write the crash report to output_dir before the process terminates.

libdd-crashtracker-ffi/Cargo.toml

@@ -20,15 +20,16 @@ bench = false
 required-features = ["collector_windows"]
 
 [features]
-default = ["cbindgen", "collector", "demangler", "receiver"]
+default = ["std", "cbindgen", "collector", "demangler", "receiver"]
+std = ["libdd-crashtracker/std"]
 cbindgen = ["build_common/cbindgen"]
 regex-lite = ["libdd-common-ffi/regex-lite"]
 # Enables the in-process collection of crash-info
-collector = []
-collector_windows = []
-demangler = ["dep:symbolic-demangle", "dep:symbolic-common"]
+collector = ["std", "libdd-crashtracker/collector"]
+collector_windows = ["std", "libdd-crashtracker/collector_windows"]
+demangler = ["std", "dep:symbolic-demangle", "dep:symbolic-common"]
 # Enables the use of this library to receiver crash-info from a suitable collector
-receiver = []
+receiver = ["std", "libdd-crashtracker/receiver"]
 
 [target.'cfg(windows)'.features]
 default = ["collector_windows"]
@@ -38,7 +39,7 @@ build_common = { path = "../build-common" }
 
 [dependencies]
 anyhow = "1.0"
-libdd-crashtracker = { path = "../libdd-crashtracker" }
+libdd-crashtracker = { path = "../libdd-crashtracker", default-features = false }
 libdd-common = { path = "../libdd-common" }
 libdd-common-ffi = { path = "../libdd-common-ffi", default-features = false }
 symbolic-demangle = { version = "12.8.0", default-features = false, features = ["rust", "cpp", "msvc"], optional = true }

libdd-crashtracker-ffi/src/lib.rs

@@ -11,19 +11,23 @@
 mod collector;
 #[cfg(all(windows, feature = "collector_windows"))]
 mod collector_windows;
+#[cfg(feature = "std")]
 mod crash_info;
 #[cfg(feature = "demangler")]
 mod demangler;
 #[cfg(all(unix, feature = "receiver"))]
 mod receiver;
+#[cfg(feature = "std")]
 mod runtime_callback;
 #[cfg(all(unix, feature = "collector"))]
 pub use collector::*;
 #[cfg(all(windows, feature = "collector_windows"))]
 pub use collector_windows::api::ddog_crasht_init_windows;
+#[cfg(feature = "std")]
 pub use crash_info::*;
 #[cfg(feature = "demangler")]
 pub use demangler::*;
 #[cfg(all(unix, feature = "receiver"))]
 pub use receiver::*;
+#[cfg(feature = "std")]
 pub use runtime_callback::*;