[INFO] cloning repository https://github.com/kuviman/snaked
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/kuviman/snaked" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkuviman%2Fsnaked", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkuviman%2Fsnaked'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 26e881349ab268c44929510b2f0a93d689697b23
[INFO] checking kuviman/snaked against master#2e6fc425411280c658d852813de01c5157255088 for pr-128013
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkuviman%2Fsnaked" "/workspace/builds/worker-2-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/kuviman/snaked on toolchain 2e6fc425411280c658d852813de01c5157255088
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+2e6fc425411280c658d852813de01c5157255088" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/kuviman/snaked
[INFO] finished tweaking git repo https://github.com/kuviman/snaked
[INFO] tweaked toml for git repo https://github.com/kuviman/snaked written to /workspace/builds/worker-2-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/kuviman/snaked 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" "+2e6fc425411280c658d852813de01c5157255088" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/geng`
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/batbox`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/web-audio-api`
[INFO] [stderr]     Updating git repository `https://github.com/rust-windowing/glutin`
[INFO] [stderr] error: failed to select a version for `bitflags`.
[INFO] [stderr]     ... required by package `ndk v0.9.0`
[INFO] [stderr]     ... which satisfies dependency `ndk = "^0.9"` of package `batbox-android v0.16.0 (https://github.com/geng-engine/batbox#1b9baf18)`
[INFO] [stderr]     ... which satisfies git dependency `batbox-android` of package `batbox v0.16.0 (https://github.com/geng-engine/batbox#1b9baf18)`
[INFO] [stderr]     ... which satisfies git dependency `batbox` of package `geng v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng` of package `snaked v0.1.0 (/workspace/builds/worker-2-tc1/source)`
[INFO] [stderr] versions that meet the requirements `^2.4` are: 2.6.0, 2.5.0, 2.4.2, 2.4.1, 2.4.0
[INFO] [stderr] 
[INFO] [stderr] all possible versions conflict with previously selected packages.
[INFO] [stderr] 
[INFO] [stderr]   previously selected package `bitflags v2.3.3`
[INFO] [stderr]     ... which satisfies dependency `bitflags = "^2.2.1"` (locked to 2.3.3) of package `glutin v0.32.0 (https://github.com/rust-windowing/glutin#90ebeb5b)`
[INFO] [stderr]     ... which satisfies git dependency `glutin` of package `geng-window v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng-window` of package `geng v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng` of package `snaked v0.1.0 (/workspace/builds/worker-2-tc1/source)`
[INFO] [stderr] 
[INFO] [stderr] failed to select a version for `bitflags` which could resolve this conflict
[ERROR] this task or one of its parent failed!
[ERROR] command failed: exit status: 101
[ERROR] note: run with `RUST_BACKTRACE=1` to display a backtrace.
[INFO] checking kuviman/snaked against try#d856f2da3433420b7077c0dc7ee9441455bc1302 for pr-128013
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkuviman%2Fsnaked" "/workspace/builds/worker-2-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/kuviman/snaked on toolchain d856f2da3433420b7077c0dc7ee9441455bc1302
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+d856f2da3433420b7077c0dc7ee9441455bc1302" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/kuviman/snaked
[INFO] finished tweaking git repo https://github.com/kuviman/snaked
[INFO] tweaked toml for git repo https://github.com/kuviman/snaked written to /workspace/builds/worker-2-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/kuviman/snaked 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" "+d856f2da3433420b7077c0dc7ee9441455bc1302" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/geng`
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/batbox`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/web-audio-api`
[INFO] [stderr]     Updating git repository `https://github.com/rust-windowing/glutin`
[INFO] [stderr] error: failed to select a version for `bitflags`.
[INFO] [stderr]     ... required by package `ndk v0.9.0`
[INFO] [stderr]     ... which satisfies dependency `ndk = "^0.9"` of package `batbox-android v0.16.0 (https://github.com/geng-engine/batbox#1b9baf18)`
[INFO] [stderr]     ... which satisfies git dependency `batbox-android` of package `batbox v0.16.0 (https://github.com/geng-engine/batbox#1b9baf18)`
[INFO] [stderr]     ... which satisfies git dependency `batbox` of package `geng v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng` of package `snaked v0.1.0 (/workspace/builds/worker-2-tc2/source)`
[INFO] [stderr] versions that meet the requirements `^2.4` are: 2.6.0, 2.5.0, 2.4.2, 2.4.1, 2.4.0
[INFO] [stderr] 
[INFO] [stderr] all possible versions conflict with previously selected packages.
[INFO] [stderr] 
[INFO] [stderr]   previously selected package `bitflags v2.3.3`
[INFO] [stderr]     ... which satisfies dependency `bitflags = "^2.2.1"` (locked to 2.3.3) of package `glutin v0.32.0 (https://github.com/rust-windowing/glutin#90ebeb5b)`
[INFO] [stderr]     ... which satisfies git dependency `glutin` of package `geng-window v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng-window` of package `geng v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng` of package `snaked v0.1.0 (/workspace/builds/worker-2-tc2/source)`
[INFO] [stderr] 
[INFO] [stderr] failed to select a version for `bitflags` which could resolve this conflict
[INFO] checking kuviman/snaked against try#d856f2da3433420b7077c0dc7ee9441455bc1302 for pr-128013
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkuviman%2Fsnaked" "/workspace/builds/worker-2-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/kuviman/snaked on toolchain d856f2da3433420b7077c0dc7ee9441455bc1302
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+d856f2da3433420b7077c0dc7ee9441455bc1302" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/kuviman/snaked
[INFO] finished tweaking git repo https://github.com/kuviman/snaked
[INFO] tweaked toml for git repo https://github.com/kuviman/snaked written to /workspace/builds/worker-2-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/kuviman/snaked 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" "+d856f2da3433420b7077c0dc7ee9441455bc1302" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/geng`
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/batbox`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/web-audio-api`
[INFO] [stderr]     Updating git repository `https://github.com/rust-windowing/glutin`
[INFO] [stderr] error: failed to select a version for `futures-channel`.
[INFO] [stderr]     ... required by package `web-audio-api v0.45.0`
[INFO] [stderr]     ... which satisfies dependency `web-audio-api = "^0.45"` of package `geng-web-audio-api v0.1.0 (https://github.com/geng-engine/web-audio-api#88fbada6)`
[INFO] [stderr]     ... which satisfies git dependency `geng-web-audio-api` of package `geng-audio v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng-audio` of package `geng v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng` of package `snaked v0.1.0 (/workspace/builds/worker-2-tc2/source)`
[INFO] [stderr] versions that meet the requirements `^0.3.30` are: 0.3.30
[INFO] [stderr] 
[INFO] [stderr] all possible versions conflict with previously selected packages.
[INFO] [stderr] 
[INFO] [stderr]   previously selected package `futures-channel v0.3.28`
[INFO] [stderr]     ... which satisfies dependency `futures-channel = "^0.3.4"` (locked to 0.3.28) of package `async-std v1.12.0`
[INFO] [stderr]     ... which satisfies dependency `async-std = "^1"` (locked to 1.12.0) of package `batbox v0.16.0 (https://github.com/geng-engine/batbox#1b9baf18)`
[INFO] [stderr]     ... which satisfies git dependency `batbox` of package `geng v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng` of package `snaked v0.1.0 (/workspace/builds/worker-2-tc2/source)`
[INFO] [stderr] 
[INFO] [stderr] failed to select a version for `futures-channel` which could resolve this conflict
[INFO] checking kuviman/snaked against try#d856f2da3433420b7077c0dc7ee9441455bc1302 for pr-128013
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkuviman%2Fsnaked" "/workspace/builds/worker-2-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/kuviman/snaked on toolchain d856f2da3433420b7077c0dc7ee9441455bc1302
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+d856f2da3433420b7077c0dc7ee9441455bc1302" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/kuviman/snaked
[INFO] finished tweaking git repo https://github.com/kuviman/snaked
[INFO] tweaked toml for git repo https://github.com/kuviman/snaked written to /workspace/builds/worker-2-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/kuviman/snaked 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" "+d856f2da3433420b7077c0dc7ee9441455bc1302" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/geng`
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/batbox`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/web-audio-api`
[INFO] [stderr]     Updating git repository `https://github.com/rust-windowing/glutin`
[INFO] [stderr] error: failed to select a version for `bitflags`.
[INFO] [stderr]     ... required by package `ndk v0.9.0`
[INFO] [stderr]     ... which satisfies dependency `ndk = "^0.9"` of package `batbox-android v0.16.0 (https://github.com/geng-engine/batbox#1b9baf18)`
[INFO] [stderr]     ... which satisfies git dependency `batbox-android` of package `batbox v0.16.0 (https://github.com/geng-engine/batbox#1b9baf18)`
[INFO] [stderr]     ... which satisfies git dependency `batbox` of package `geng v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng` of package `snaked v0.1.0 (/workspace/builds/worker-2-tc2/source)`
[INFO] [stderr] versions that meet the requirements `^2.4` are: 2.6.0, 2.5.0, 2.4.2, 2.4.1, 2.4.0
[INFO] [stderr] 
[INFO] [stderr] all possible versions conflict with previously selected packages.
[INFO] [stderr] 
[INFO] [stderr]   previously selected package `bitflags v2.3.3`
[INFO] [stderr]     ... which satisfies dependency `bitflags = "^2.2.1"` (locked to 2.3.3) of package `glutin v0.32.0 (https://github.com/rust-windowing/glutin#90ebeb5b)`
[INFO] [stderr]     ... which satisfies git dependency `glutin` of package `geng-window v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng-window` of package `geng v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng` of package `snaked v0.1.0 (/workspace/builds/worker-2-tc2/source)`
[INFO] [stderr] 
[INFO] [stderr] failed to select a version for `bitflags` which could resolve this conflict
[INFO] checking kuviman/snaked against try#d856f2da3433420b7077c0dc7ee9441455bc1302 for pr-128013
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkuviman%2Fsnaked" "/workspace/builds/worker-2-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/kuviman/snaked on toolchain d856f2da3433420b7077c0dc7ee9441455bc1302
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+d856f2da3433420b7077c0dc7ee9441455bc1302" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/kuviman/snaked
[INFO] finished tweaking git repo https://github.com/kuviman/snaked
[INFO] tweaked toml for git repo https://github.com/kuviman/snaked written to /workspace/builds/worker-2-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/kuviman/snaked 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" "+d856f2da3433420b7077c0dc7ee9441455bc1302" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/geng`
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/batbox`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/web-audio-api`
[INFO] [stderr]     Updating git repository `https://github.com/rust-windowing/glutin`
[INFO] [stderr] error: failed to select a version for `bitflags`.
[INFO] [stderr]     ... required by package `ndk v0.9.0`
[INFO] [stderr]     ... which satisfies dependency `ndk = "^0.9"` of package `batbox-android v0.16.0 (https://github.com/geng-engine/batbox#1b9baf18)`
[INFO] [stderr]     ... which satisfies git dependency `batbox-android` of package `batbox v0.16.0 (https://github.com/geng-engine/batbox#1b9baf18)`
[INFO] [stderr]     ... which satisfies git dependency `batbox` of package `geng v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng` of package `snaked v0.1.0 (/workspace/builds/worker-2-tc2/source)`
[INFO] [stderr] versions that meet the requirements `^2.4` are: 2.6.0, 2.5.0, 2.4.2, 2.4.1, 2.4.0
[INFO] [stderr] 
[INFO] [stderr] all possible versions conflict with previously selected packages.
[INFO] [stderr] 
[INFO] [stderr]   previously selected package `bitflags v2.3.3`
[INFO] [stderr]     ... which satisfies dependency `bitflags = "^2.2.1"` (locked to 2.3.3) of package `glutin v0.32.0 (https://github.com/rust-windowing/glutin#90ebeb5b)`
[INFO] [stderr]     ... which satisfies git dependency `glutin` of package `geng-window v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng-window` of package `geng v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng` of package `snaked v0.1.0 (/workspace/builds/worker-2-tc2/source)`
[INFO] [stderr] 
[INFO] [stderr] failed to select a version for `bitflags` which could resolve this conflict
[INFO] checking kuviman/snaked against try#d856f2da3433420b7077c0dc7ee9441455bc1302 for pr-128013
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkuviman%2Fsnaked" "/workspace/builds/worker-2-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/kuviman/snaked on toolchain d856f2da3433420b7077c0dc7ee9441455bc1302
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+d856f2da3433420b7077c0dc7ee9441455bc1302" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/kuviman/snaked
[INFO] finished tweaking git repo https://github.com/kuviman/snaked
[INFO] tweaked toml for git repo https://github.com/kuviman/snaked written to /workspace/builds/worker-2-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/kuviman/snaked 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" "+d856f2da3433420b7077c0dc7ee9441455bc1302" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/geng`
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/batbox`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Updating git repository `https://github.com/geng-engine/web-audio-api`
[INFO] [stderr]     Updating git repository `https://github.com/rust-windowing/glutin`
[INFO] [stderr] error: failed to select a version for `futures-channel`.
[INFO] [stderr]     ... required by package `web-audio-api v0.45.0`
[INFO] [stderr]     ... which satisfies dependency `web-audio-api = "^0.45"` of package `geng-web-audio-api v0.1.0 (https://github.com/geng-engine/web-audio-api#88fbada6)`
[INFO] [stderr]     ... which satisfies git dependency `geng-web-audio-api` of package `geng-audio v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng-audio` of package `geng v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng` of package `snaked v0.1.0 (/workspace/builds/worker-2-tc2/source)`
[INFO] [stderr] versions that meet the requirements `^0.3.30` are: 0.3.30
[INFO] [stderr] 
[INFO] [stderr] all possible versions conflict with previously selected packages.
[INFO] [stderr] 
[INFO] [stderr]   previously selected package `futures-channel v0.3.28`
[INFO] [stderr]     ... which satisfies dependency `futures-channel = "^0.3.4"` (locked to 0.3.28) of package `async-std v1.12.0`
[INFO] [stderr]     ... which satisfies dependency `async-std = "^1"` (locked to 1.12.0) of package `batbox v0.16.0 (https://github.com/geng-engine/batbox#1b9baf18)`
[INFO] [stderr]     ... which satisfies git dependency `batbox` of package `geng v0.18.0 (https://github.com/geng-engine/geng#ad453b8b)`
[INFO] [stderr]     ... which satisfies git dependency `geng` of package `snaked v0.1.0 (/workspace/builds/worker-2-tc2/source)`
[INFO] [stderr] 
[INFO] [stderr] failed to select a version for `futures-channel` which could resolve this conflict
[ERROR] this task or one of its parent failed!
[ERROR] command failed: exit status: 101
[ERROR] note: run with `RUST_BACKTRACE=1` to display a backtrace.