feat(profiling): Wrap libunwind in a crate (#1510)

# What does this PR do?

Wrap libunwind in `libdd-libunwind-sys` Rust crate. 

# Motivation

Crashtracker collects callstacks. When it comes to alpine/musl-libc (mainly on x86_64), we fail at retrieving the callstack passed the signal frame. The problem is that the musl-libc binary does not have the CFIs (unwinding information) and the unwinder does not know how to move forward and stop.

Libunwind provides a way to unwind starting from the ucontext: context (registers and state) of the crashing thread. Going that way, we can collect the callstack as much as possible (until hitting musl-libc)

# Additional Notes

Gitlab jobs have been modified in this [PR ](DataDog/libddprof-build#149 it's working https://gitlab.ddbuild.io/DataDog/apm-reliability/libddprof-build/-/pipelines/100326074.



Co-authored-by: gregory.leocadie <gregory.leocadie@datadoghq.com>

Author: gleocadie

.github/CODEOWNERS

@@ -14,6 +14,7 @@
 .gitlab-ci.yml                       @DataDog/apm-common-components-core
 .gitlab/benchmarks.yml               @DataDog/apm-common-components-core
 .gitlab/fuzz.yml                     @DataDog/chaos-platform
+.gitmodules                          @DataDog/libdatadog
 benchmark/                           @DataDog/apm-common-components-core
 bin_tests/                           @DataDog/libdatadog-profiling
 build-common/                        @DataDog/apm-common-components-core
@@ -44,6 +45,7 @@ libdd-data-pipeline*/                @DataDog/libdatadog-apm
 libdd-ddsketch*/                     @DataDog/libdatadog-apm @DataDog/apm-common-components-core
 libdd-dogstatsd-client               @DataDog/apm-common-components-core
 libdd-library-config*/               @DataDog/apm-sdk-capabilities
+libdd-libunwind*/                    @DataDog/libdatadog-profiling
 libdd-log*/                          @DataDog/apm-common-components-core
 libdd-profiling*/                    @DataDog/libdatadog-profiling
 libdd-telemetry*/                    @DataDog/apm-common-components-core

.github/workflows/coverage.yml

@@ -26,6 +26,8 @@ jobs:
           docker-images: true
           swap-storage: true
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
+        with:
+          submodules: recursive
       - name: Install Rust
         run: rustup install nightly-2026-02-08 && rustup default nightly-2026-02-08
       - name: Install cargo-llvm-cov

.github/workflows/lint.yml

@@ -10,6 +10,8 @@ jobs:
     steps:
       - name: Checkout sources
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
+        with:
+          submodules: recursive
       - name: Run actionlint
         uses: devops-actions/actionlint@c6744a34774e4e1c1df0ff66bdb07ec7ee480ca0 # 0.1.9
         with:
@@ -22,6 +24,8 @@ jobs:
     steps:
       - name: Checkout sources
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
+        with:
+          submodules: recursive
       - name: Install nightly-2026-02-08 toolchain and rustfmt
         run: rustup install nightly-2026-02-08 && rustup default nightly-2026-02-08 && rustup component add rustfmt
       - name: Cache [rust]
@@ -41,6 +45,8 @@ jobs:
     steps:
       - name: Checkout sources
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
+        with:
+          submodules: recursive
       - name: Install ${{ matrix.rust_version }} toolchain and clippy
         run: rustup install ${{ matrix.rust_version }} && rustup default ${{ matrix.rust_version }} && rustup component add clippy
       - name: Cache [rust]

.github/workflows/miri.yml

@@ -14,6 +14,8 @@ jobs:
       PROPTEST_CASES: 1
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
+        with:
+          submodules: recursive
       - name: Set up Rust
         run: |
           set -e

.github/workflows/test.yml

@@ -36,6 +36,8 @@ jobs:
           swap-storage: true
       - name: Checkout sources
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
+        with:
+          submodules: recursive
       - name: Install Rust ${{ matrix.rust_version }}
         if: matrix.rust_version != ''
         run: rustup install ${{ matrix.rust_version }} && rustup default ${{ matrix.rust_version }}
@@ -155,6 +157,8 @@ jobs:
     steps:
       - name: Checkout sources
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
+        with:
+          submodules: recursive
       - name: Setup output dir
         shell: bash
         run: |
@@ -297,6 +301,8 @@ jobs:
           swap-storage: true
       - name: Checkout
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
+        with:
+          submodules: recursive
       - name: Cache [rust]
         uses: Swatinem/rust-cache@f13886b937689c021905a6b90929199931d60db1 # 2.8.1
         with:
@@ -321,6 +327,8 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
+        with:
+          submodules: recursive
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@b5ca514318bd6ebac0fb2aedd5d36ec1b5c232a2 # 3.10.0
         with:

.gitmodules

@@ -0,0 +1,4 @@
+[submodule "libdd-libunwind-sys/libunwind"]
+	path = libdd-libunwind-sys/libunwind
+	url = https://github.com/DataDog/libunwind.git
+	branch = kevin/v1.8.1-custom-2

Cargo.lock

@@ -46,7 +46,7 @@ members = [
   "libdd-tinybytes",
   "libdd-dogstatsd-client",
   "libdd-log",
-  "libdd-log-ffi",
+  "libdd-log-ffi", "libdd-libunwind-sys",
 ]
 
 # https://doc.rust-lang.org/cargo/reference/resolver.html

Cargo.toml

@@ -1,4 +1,4 @@
-root_name: builder, build_common, tools, libdd-alloc, libdd-crashtracker, libdd-common, libdd-telemetry, libdd-ddsketch, libdd-crashtracker-ffi, libdd-common-ffi, datadog-ffe, datadog-ffe-ffi, datadog-ipc, datadog-ipc-macros, libdd-tinybytes, tarpc, tarpc-plugins, spawn_worker, cc_utils, libdd-library-config, libdd-library-config-ffi, datadog-live-debugger, libdd-data-pipeline, libdd-dogstatsd-client, libdd-trace-protobuf, libdd-trace-stats, libdd-trace-utils, libdd-trace-normalization, libdd-log, datadog-live-debugger-ffi, libdd-profiling, libdd-profiling-protobuf, libdd-profiling-ffi, libdd-data-pipeline-ffi, libdd-ddsketch-ffi, libdd-log-ffi, libdd-telemetry-ffi, symbolizer-ffi, datadog-profiling-replayer, datadog-remote-config, datadog-sidecar, datadog-sidecar-macros, datadog-sidecar-ffi, libdd-trace-obfuscation, datadog-tracer-flare, sidecar_mockgen, test_spawn_from_lib
+root_name: builder, build_common, tools, libdd-alloc, libdd-crashtracker, libdd-common, libdd-telemetry, libdd-ddsketch, libdd-crashtracker-ffi, libdd-common-ffi, datadog-ffe, datadog-ffe-ffi, datadog-ipc, datadog-ipc-macros, libdd-tinybytes, tarpc, tarpc-plugins, spawn_worker, cc_utils, libdd-library-config, libdd-library-config-ffi, datadog-live-debugger, libdd-data-pipeline, libdd-dogstatsd-client, libdd-trace-protobuf, libdd-trace-stats, libdd-trace-utils, libdd-trace-normalization, libdd-log, datadog-live-debugger-ffi, libdd-profiling, libdd-profiling-protobuf, libdd-profiling-ffi, libdd-data-pipeline-ffi, libdd-ddsketch-ffi, libdd-log-ffi, libdd-telemetry-ffi, symbolizer-ffi, datadog-profiling-replayer, datadog-remote-config, datadog-sidecar, datadog-sidecar-macros, datadog-sidecar-ffi, libdd-trace-obfuscation, datadog-tracer-flare, sidecar_mockgen, test_spawn_from_lib, bin_tests
 third_party_libraries:
 - package_name: addr2line
   package_version: 0.24.2

LICENSE-3rdparty.yml

@@ -0,0 +1,19 @@
+[package]
+name = "libdd-libunwind"
+edition.workspace = true
+version.workspace = true
+rust-version.workspace = true
+license.workspace = true
+publish = false
+links = "unwind"  # Tells Cargo this crate links to libunwind (prevents multiple builds)
+
+[lib]
+crate-type = ["lib"]
+bench = false
+
+[dependencies]
+paste = "1.0"
+libc = "0.2"
+
+[build-dependencies]
+cc = "1.0"