[INFO] cloning repository https://github.com/nick1udwig/serialize-store-test [INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/nick1udwig/serialize-store-test" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnick1udwig%2Fserialize-store-test", kill_on_drop: false }` [INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnick1udwig%2Fserialize-store-test'... [INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }` [INFO] [stdout] 00e129c6bbc2ce8340375dc061bc3698b8bbc40c [INFO] building nick1udwig/serialize-store-test against master#70591dc15db32941fe3595fdbf98e58d6975f95e for pr-127731 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnick1udwig%2Fserialize-store-test" "/workspace/builds/worker-5-tc1/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc1/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/nick1udwig/serialize-store-test on toolchain 70591dc15db32941fe3595fdbf98e58d6975f95e [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+70591dc15db32941fe3595fdbf98e58d6975f95e" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/nick1udwig/serialize-store-test [INFO] finished tweaking git repo https://github.com/nick1udwig/serialize-store-test [INFO] tweaked toml for git repo https://github.com/nick1udwig/serialize-store-test written to /workspace/builds/worker-5-tc1/source/Cargo.toml [INFO] crate git repo https://github.com/nick1udwig/serialize-store-test already has a lockfile, it will not be regenerated [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+70591dc15db32941fe3595fdbf98e58d6975f95e" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] [stderr] Blocking waiting for file lock on package cache [INFO] [stderr] Downloading crates ... [INFO] [stderr] Downloaded wat v1.205.0 [INFO] [stderr] Downloaded cap-rand v3.0.0 [INFO] [stderr] Downloaded cap-fs-ext v3.0.0 [INFO] [stderr] Downloaded cap-net-ext v3.0.0 [INFO] [stderr] Downloaded cap-time-ext v3.0.0 [INFO] [stderr] Downloaded cap-std v3.0.0 [INFO] [stderr] Downloaded wast v205.0.0 [INFO] [stderr] Downloaded cap-primitives v3.0.0 [INFO] [stderr] Downloaded wasm-encoder v0.205.0 [INFO] [stderr] warning: failed to save last-use data [INFO] [stderr] This may prevent cargo from accurately tracking what is being used in its global cache. This information is used for automatically removing unused data in the cache. [INFO] [stderr] [INFO] [stderr] database or disk is full [INFO] [stderr] [INFO] [stderr] Caused by: [INFO] [stderr] Error code 13: Insertion failed because database is full [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+70591dc15db32941fe3595fdbf98e58d6975f95e" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stdout] 9545de9492fc572c55438f6d35013e0e15b637efaabdf9d2bbaa0da7ff3d5c37 [INFO] running `Command { std: "docker" "start" "-a" "9545de9492fc572c55438f6d35013e0e15b637efaabdf9d2bbaa0da7ff3d5c37", kill_on_drop: false }` [INFO] running `Command { std: "docker" "inspect" "9545de9492fc572c55438f6d35013e0e15b637efaabdf9d2bbaa0da7ff3d5c37", kill_on_drop: false }` [INFO] running `Command { std: "docker" "rm" "-f" "9545de9492fc572c55438f6d35013e0e15b637efaabdf9d2bbaa0da7ff3d5c37", kill_on_drop: false }` [INFO] [stdout] 9545de9492fc572c55438f6d35013e0e15b637efaabdf9d2bbaa0da7ff3d5c37 [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+70591dc15db32941fe3595fdbf98e58d6975f95e" "build" "--frozen" "--message-format=json", kill_on_drop: false }` [INFO] [stdout] 00feb927ca4d3898f7ccb767bdb91e0f5269c87cc250a180e7a7edce4536a628 [INFO] running `Command { std: "docker" "start" "-a" "00feb927ca4d3898f7ccb767bdb91e0f5269c87cc250a180e7a7edce4536a628", kill_on_drop: false }` [INFO] [stderr] error: failed to create directory `/opt/rustwide/target/debug/build/proc-macro2-7acd2664a55e8ea7/out` [INFO] [stderr] [INFO] [stderr] Caused by: [INFO] [stderr] No space left on device (os error 28) [INFO] running `Command { std: "docker" "inspect" "00feb927ca4d3898f7ccb767bdb91e0f5269c87cc250a180e7a7edce4536a628", kill_on_drop: false }` [INFO] running `Command { std: "docker" "rm" "-f" "00feb927ca4d3898f7ccb767bdb91e0f5269c87cc250a180e7a7edce4536a628", kill_on_drop: false }` [INFO] [stdout] 00feb927ca4d3898f7ccb767bdb91e0f5269c87cc250a180e7a7edce4536a628 [INFO] building nick1udwig/serialize-store-test against try#7587ff3622fbec0abf6ac551eab5226f22f5d958 for pr-127731 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnick1udwig%2Fserialize-store-test" "/workspace/builds/worker-5-tc2/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc2/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/nick1udwig/serialize-store-test on toolchain 7587ff3622fbec0abf6ac551eab5226f22f5d958 [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+7587ff3622fbec0abf6ac551eab5226f22f5d958" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/nick1udwig/serialize-store-test [INFO] finished tweaking git repo https://github.com/nick1udwig/serialize-store-test [INFO] tweaked toml for git repo https://github.com/nick1udwig/serialize-store-test written to /workspace/builds/worker-5-tc2/source/Cargo.toml [INFO] crate git repo https://github.com/nick1udwig/serialize-store-test already has a lockfile, it will not be regenerated [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+7587ff3622fbec0abf6ac551eab5226f22f5d958" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] [stderr] Blocking waiting for file lock on package cache [INFO] [stderr] warning: failed to save last-use data [INFO] [stderr] This may prevent cargo from accurately tracking what is being used in its global cache. This information is used for automatically removing unused data in the cache. [INFO] [stderr] [INFO] [stderr] database or disk is full [INFO] [stderr] [INFO] [stderr] Caused by: [INFO] [stderr] Error code 13: Insertion failed because database is full [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+7587ff3622fbec0abf6ac551eab5226f22f5d958" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stdout] 31e9eca5343fc6bb99d6a8045ec38459ae7f77af656d06b48cb52188aa7ded25 [INFO] running `Command { std: "docker" "start" "-a" "31e9eca5343fc6bb99d6a8045ec38459ae7f77af656d06b48cb52188aa7ded25", kill_on_drop: false }` [INFO] running `Command { std: "docker" "inspect" "31e9eca5343fc6bb99d6a8045ec38459ae7f77af656d06b48cb52188aa7ded25", kill_on_drop: false }` [INFO] running `Command { std: "docker" "rm" "-f" "31e9eca5343fc6bb99d6a8045ec38459ae7f77af656d06b48cb52188aa7ded25", kill_on_drop: false }` [INFO] [stdout] 31e9eca5343fc6bb99d6a8045ec38459ae7f77af656d06b48cb52188aa7ded25 [INFO] building nick1udwig/serialize-store-test against try#7587ff3622fbec0abf6ac551eab5226f22f5d958 for pr-127731 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnick1udwig%2Fserialize-store-test" "/workspace/builds/worker-5-tc2/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc2/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/nick1udwig/serialize-store-test on toolchain 7587ff3622fbec0abf6ac551eab5226f22f5d958 [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+7587ff3622fbec0abf6ac551eab5226f22f5d958" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/nick1udwig/serialize-store-test [INFO] finished tweaking git repo https://github.com/nick1udwig/serialize-store-test [INFO] tweaked toml for git repo https://github.com/nick1udwig/serialize-store-test written to /workspace/builds/worker-5-tc2/source/Cargo.toml [INFO] crate git repo https://github.com/nick1udwig/serialize-store-test already has a lockfile, it will not be regenerated [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+7587ff3622fbec0abf6ac551eab5226f22f5d958" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] [stderr] Blocking waiting for file lock on package cache [INFO] [stderr] warning: failed to save last-use data [INFO] [stderr] This may prevent cargo from accurately tracking what is being used in its global cache. This information is used for automatically removing unused data in the cache. [INFO] [stderr] [INFO] [stderr] database or disk is full [INFO] [stderr] [INFO] [stderr] Caused by: [INFO] [stderr] Error code 13: Insertion failed because database is full [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+7587ff3622fbec0abf6ac551eab5226f22f5d958" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stderr] Error response from daemon: chown /var/lib/docker/overlay2/77dc6f1d79f7ef5294fcb4330e54e0996aa6483db8a1efabd671fb4925ba8735/work/work: no such file or directory [INFO] building nick1udwig/serialize-store-test against try#7587ff3622fbec0abf6ac551eab5226f22f5d958 for pr-127731 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnick1udwig%2Fserialize-store-test" "/workspace/builds/worker-5-tc2/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc2/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/nick1udwig/serialize-store-test on toolchain 7587ff3622fbec0abf6ac551eab5226f22f5d958 [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+7587ff3622fbec0abf6ac551eab5226f22f5d958" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/nick1udwig/serialize-store-test [INFO] finished tweaking git repo https://github.com/nick1udwig/serialize-store-test [INFO] tweaked toml for git repo https://github.com/nick1udwig/serialize-store-test written to /workspace/builds/worker-5-tc2/source/Cargo.toml [INFO] crate git repo https://github.com/nick1udwig/serialize-store-test already has a lockfile, it will not be regenerated [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+7587ff3622fbec0abf6ac551eab5226f22f5d958" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] [stderr] Blocking waiting for file lock on package cache [INFO] [stderr] warning: failed to save last-use data [INFO] [stderr] This may prevent cargo from accurately tracking what is being used in its global cache. This information is used for automatically removing unused data in the cache. [INFO] [stderr] [INFO] [stderr] database or disk is full [INFO] [stderr] [INFO] [stderr] Caused by: [INFO] [stderr] Error code 13: Insertion failed because database is full [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+7587ff3622fbec0abf6ac551eab5226f22f5d958" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stderr] Error response from daemon: write /var/lib/docker/image/overlay2/layerdb/mounts/952fe3d730c396cfc8b52944139bd95e25b4f6d0166043df17b93d603462355e/init-id: no space left on device [INFO] building nick1udwig/serialize-store-test against try#7587ff3622fbec0abf6ac551eab5226f22f5d958 for pr-127731 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnick1udwig%2Fserialize-store-test" "/workspace/builds/worker-5-tc2/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc2/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/nick1udwig/serialize-store-test on toolchain 7587ff3622fbec0abf6ac551eab5226f22f5d958 [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+7587ff3622fbec0abf6ac551eab5226f22f5d958" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/nick1udwig/serialize-store-test [INFO] finished tweaking git repo https://github.com/nick1udwig/serialize-store-test [INFO] tweaked toml for git repo https://github.com/nick1udwig/serialize-store-test written to /workspace/builds/worker-5-tc2/source/Cargo.toml [INFO] crate git repo https://github.com/nick1udwig/serialize-store-test already has a lockfile, it will not be regenerated [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+7587ff3622fbec0abf6ac551eab5226f22f5d958" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] [stderr] Blocking waiting for file lock on package cache [INFO] [stderr] warning: failed to save last-use data [INFO] [stderr] This may prevent cargo from accurately tracking what is being used in its global cache. This information is used for automatically removing unused data in the cache. [INFO] [stderr] [INFO] [stderr] database or disk is full [INFO] [stderr] [INFO] [stderr] Caused by: [INFO] [stderr] Error code 13: Insertion failed because database is full [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+7587ff3622fbec0abf6ac551eab5226f22f5d958" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stderr] Error response from daemon: mkdir /var/lib/docker/overlay2/8d5ec7b3a7b5671f14309387499c43313f2dfbb853909920929d71f39c213cf3-init: no space left on device [INFO] building nick1udwig/serialize-store-test against try#7587ff3622fbec0abf6ac551eab5226f22f5d958 for pr-127731 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnick1udwig%2Fserialize-store-test" "/workspace/builds/worker-5-tc2/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc2/source'... [INFO] [stderr] done. [INFO] [stderr] fatal: unable to write new index file [INFO] [stderr] warning: Clone succeeded, but checkout failed. [INFO] [stderr] You can inspect what was checked out with 'git status' [INFO] [stderr] and retry with 'git restore --source=HEAD :/' [INFO] [stderr] [ERROR] this task or one of its parent failed! [ERROR] failed to checkout https://github.com/nick1udwig/serialize-store-test [ERROR] caused by: command failed: exit status: 128 [ERROR] note: run with `RUST_BACKTRACE=1` to display a backtrace.