Rust 1.93.0 / LLVM 21.1.8; x86_64 Linux / CPython 3.14.4.
Separate AddressSanitizer build; production wheel was not replaced.

Native build:
RUSTC_BOOTSTRAP=1 RUSTFLAGS=-Zsanitizer=address CARGO_HOME=/tmp/skirr-cargo CARGO_TARGET_DIR=/tmp/skirr-asan-target PYO3_PYTHON=/usr/bin/python cargo build --release --target x86_64-unknown-linux-gnu --features extension-module

Runtime:
LLVM runtime from rustc's librustc-stable_rt.asan.a, copied to /tmp;
asan_preinit.cpp.o removed from that copy because it is executable-only;
remaining archive linked as a shared runtime with gcc --whole-archive,
-ldl -lpthread -lrt -lm. Preloaded into the Python test process.

Test environment:
LD_PRELOAD=/tmp/skirr-asan-runtime.so ASAN_OPTIONS=detect_leaks=0
PYTHONMALLOC=malloc PYTHONPATH=/tmp/skirr-asan-package

Results:
python -m pytest tests -q: 45 passed, no sanitizer findings.
uvloop installed as asyncio policy, same suite: 45 passed, no sanitizer findings.

Scope: instrumented Rust extension/dependencies within the ordinary Python host.
Python and system libraries were not rebuilt with instrumentation. Leak detection
was disabled for the embedding host. This does not establish absence of all
memory bugs or leaks, nor replace fuzzing and multi-version qualification.