[INFO] cloning repository https://github.com/achim-k/pi-telegram-modem-dooropener
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/achim-k/pi-telegram-modem-dooropener" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fachim-k%2Fpi-telegram-modem-dooropener", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fachim-k%2Fpi-telegram-modem-dooropener'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 7d74d8a6770fc3a2209eb9a6f75fc2c15c290817
[INFO] checking achim-k/pi-telegram-modem-dooropener against master#bbefc9837f4157cc09ed60e6d7b21e345d582dd9 for pr-114571-3
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fachim-k%2Fpi-telegram-modem-dooropener" "/workspace/builds/worker-1-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/achim-k/pi-telegram-modem-dooropener on toolchain bbefc9837f4157cc09ed60e6d7b21e345d582dd9
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+bbefc9837f4157cc09ed60e6d7b21e345d582dd9" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] removed /workspace/builds/worker-1-tc1/source/.cargo/config.toml
[INFO] started tweaking git repo https://github.com/achim-k/pi-telegram-modem-dooropener
[INFO] finished tweaking git repo https://github.com/achim-k/pi-telegram-modem-dooropener
[INFO] tweaked toml for git repo https://github.com/achim-k/pi-telegram-modem-dooropener written to /workspace/builds/worker-1-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/achim-k/pi-telegram-modem-dooropener 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" "+bbefc9837f4157cc09ed60e6d7b21e345d582dd9" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded takecell v0.1.1
[INFO] [stderr]   Downloaded rc-box v1.2.0
[INFO] [stderr]   Downloaded teloxide-macros v0.6.2
[INFO] [stderr]   Downloaded erasable v1.2.1
[INFO] [stderr]   Downloaded dptree v0.2.1
[INFO] [stderr]   Downloaded openssl-sys v0.9.74
[INFO] [stderr]   Downloaded hyper v0.14.19
[INFO] [stderr]   Downloaded mio-serial v5.0.2
[INFO] [stderr]   Downloaded teloxide-core v0.6.1
[INFO] [stderr]   Downloaded tokio-serial v5.4.3
[INFO] [stderr]   Downloaded aquamarine v0.1.11
[INFO] [stderr]   Downloaded openssl-src v111.21.0+1.1.1p
[INFO] [stderr]   Downloaded teloxide v0.9.2
[INFO] [stderr]   Downloaded tracing-core v0.1.27
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+bbefc9837f4157cc09ed60e6d7b21e345d582dd9" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 3c3c97c4bac954fa5842ff353f2d8443d1e0e0a397f0beea3e4813e55229c0b2
[INFO] running `Command { std: "docker" "start" "-a" "3c3c97c4bac954fa5842ff353f2d8443d1e0e0a397f0beea3e4813e55229c0b2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "3c3c97c4bac954fa5842ff353f2d8443d1e0e0a397f0beea3e4813e55229c0b2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3c3c97c4bac954fa5842ff353f2d8443d1e0e0a397f0beea3e4813e55229c0b2", kill_on_drop: false }`
[INFO] [stdout] 3c3c97c4bac954fa5842ff353f2d8443d1e0e0a397f0beea3e4813e55229c0b2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+bbefc9837f4157cc09ed60e6d7b21e345d582dd9" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] dbd177a81774ae6d914b8bea0bcbb17a79eac4bc2a0b3b966caac95eb4ff4c2e
[INFO] running `Command { std: "docker" "start" "-a" "dbd177a81774ae6d914b8bea0bcbb17a79eac4bc2a0b3b966caac95eb4ff4c2e", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.39
[INFO] [stderr]    Compiling syn v1.0.96
[INFO] [stderr]    Compiling libc v0.2.126
[INFO] [stderr]    Compiling log v0.4.17
[INFO] [stderr]     Checking once_cell v1.12.0
[INFO] [stderr]    Compiling openssl-src v111.21.0+1.1.1p
[INFO] [stderr]    Compiling futures-util v0.3.21
[INFO] [stderr]     Checking slab v0.4.6
[INFO] [stderr]     Checking itoa v1.0.2
[INFO] [stderr]    Compiling serde_derive v1.0.137
[INFO] [stderr]    Compiling indexmap v1.8.2
[INFO] [stderr]    Compiling serde v1.0.137
[INFO] [stderr]    Compiling openssl v0.10.40
[INFO] [stderr]    Compiling strsim v0.10.0
[INFO] [stderr]    Compiling ident_case v1.0.1
[INFO] [stderr]     Checking unicode-normalization v0.1.19
[INFO] [stderr]    Compiling mime_guess v2.0.4
[INFO] [stderr]     Checking http v0.2.8
[INFO] [stderr]     Checking tracing-core v0.1.27
[INFO] [stderr]    Compiling erasable v1.2.1
[INFO] [stderr]     Checking ryu v1.0.10
[INFO] [stderr]    Compiling openssl-sys v0.9.74
[INFO] [stderr]    Compiling serde_json v1.0.81
[INFO] [stderr]     Checking aho-corasick v0.7.18
[INFO] [stderr]     Checking regex-syntax v0.6.26
[INFO] [stderr]    Compiling either v1.6.1
[INFO] [stderr]     Checking chrono v0.4.19
[INFO] [stderr]     Checking take_mut v0.2.2
[INFO] [stderr]     Checking want v0.3.0
[INFO] [stderr]    Compiling itertools v0.9.0
[INFO] [stderr]     Checking takecell v0.1.1
[INFO] [stderr]     Checking tracing v0.1.35
[INFO] [stderr]     Checking rc-box v1.2.0
[INFO] [stderr]    Compiling quote v1.0.18
[INFO] [stderr]     Checking idna v0.2.3
[INFO] [stderr]     Checking http-body v0.4.5
[INFO] [stderr]    Compiling proc-macro-error-attr v1.0.4
[INFO] [stderr]     Checking mio v0.8.3
[INFO] [stderr]     Checking num_cpus v1.13.1
[INFO] [stderr]     Checking signal-hook-registry v1.4.0
[INFO] [stderr]     Checking socket2 v0.4.4
[INFO] [stderr]     Checking getrandom v0.2.7
[INFO] [stderr]     Checking nix v0.24.1
[INFO] [stderr]     Checking nix v0.23.1
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking uuid v0.8.2
[INFO] [stderr]     Checking regex v1.5.6
[INFO] [stderr]     Checking env_logger v0.7.1
[INFO] [stderr]     Checking serialport v4.2.0
[INFO] [stderr]     Checking pretty_env_logger v0.4.0
[INFO] [stderr]    Compiling darling_core v0.13.4
[INFO] [stderr]    Compiling proc-macro-error v1.0.4
[INFO] [stderr]     Checking mio-serial v5.0.2
[INFO] [stderr]    Compiling tokio-macros v1.8.0
[INFO] [stderr]    Compiling futures-macro v0.3.21
[INFO] [stderr]    Compiling openssl-macros v0.1.0
[INFO] [stderr]     Checking tokio v1.19.2
[INFO] [stderr]    Compiling darling_macro v0.13.4
[INFO] [stderr]    Compiling pin-project-internal v1.0.10
[INFO] [stderr]    Compiling thiserror-impl v1.0.31
[INFO] [stderr]    Compiling derive_more v0.99.17
[INFO] [stderr]    Compiling darling v0.13.4
[INFO] [stderr]    Compiling serde_with_macros v1.5.2
[INFO] [stderr]    Compiling aquamarine v0.1.11
[INFO] [stderr]    Compiling teloxide-macros v0.6.2
[INFO] [stderr]     Checking pin-project v1.0.10
[INFO] [stderr]     Checking thiserror v1.0.31
[INFO] [stderr]     Checking futures-executor v0.3.21
[INFO] [stderr]     Checking futures v0.3.21
[INFO] [stderr]     Checking dptree v0.2.1
[INFO] [stderr]     Checking tokio-util v0.7.3
[INFO] [stderr]     Checking tokio-util v0.6.10
[INFO] [stderr]     Checking tokio-stream v0.1.9
[INFO] [stderr]     Checking tokio-serial v5.4.3
[INFO] [stderr]     Checking h2 v0.3.13
[INFO] [stderr]     Checking serde_urlencoded v0.7.1
[INFO] [stderr]     Checking hyper v0.14.19
[INFO] [stderr]     Checking url v2.2.2
[INFO] [stderr]    Compiling native-tls v0.2.10
[INFO] [stderr]     Checking tokio-native-tls v0.3.0
[INFO] [stderr]     Checking hyper-tls v0.5.0
[INFO] [stderr]     Checking reqwest v0.11.11
[INFO] [stderr]     Checking teloxide-core v0.6.1
[INFO] [stderr]     Checking teloxide v0.9.2
[INFO] [stderr]     Checking pi-telegram-modem-dooropener v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 24.93s
[INFO] running `Command { std: "docker" "inspect" "dbd177a81774ae6d914b8bea0bcbb17a79eac4bc2a0b3b966caac95eb4ff4c2e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "dbd177a81774ae6d914b8bea0bcbb17a79eac4bc2a0b3b966caac95eb4ff4c2e", kill_on_drop: false }`
[INFO] [stdout] dbd177a81774ae6d914b8bea0bcbb17a79eac4bc2a0b3b966caac95eb4ff4c2e
[INFO] checking achim-k/pi-telegram-modem-dooropener against try#2399cef65c47f346b5fa9df51f48df0acd4a9d85 for pr-114571-3
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fachim-k%2Fpi-telegram-modem-dooropener" "/workspace/builds/worker-1-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/achim-k/pi-telegram-modem-dooropener on toolchain 2399cef65c47f346b5fa9df51f48df0acd4a9d85
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+2399cef65c47f346b5fa9df51f48df0acd4a9d85" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] removed /workspace/builds/worker-1-tc2/source/.cargo/config.toml
[INFO] started tweaking git repo https://github.com/achim-k/pi-telegram-modem-dooropener
[INFO] finished tweaking git repo https://github.com/achim-k/pi-telegram-modem-dooropener
[INFO] tweaked toml for git repo https://github.com/achim-k/pi-telegram-modem-dooropener written to /workspace/builds/worker-1-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/achim-k/pi-telegram-modem-dooropener 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" "+2399cef65c47f346b5fa9df51f48df0acd4a9d85" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[ERROR] error running command: no output for 300 seconds
[INFO] checking achim-k/pi-telegram-modem-dooropener against try#2399cef65c47f346b5fa9df51f48df0acd4a9d85 for pr-114571-3
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fachim-k%2Fpi-telegram-modem-dooropener" "/workspace/builds/worker-1-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/achim-k/pi-telegram-modem-dooropener on toolchain 2399cef65c47f346b5fa9df51f48df0acd4a9d85
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+2399cef65c47f346b5fa9df51f48df0acd4a9d85" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] removed /workspace/builds/worker-1-tc2/source/.cargo/config.toml
[INFO] started tweaking git repo https://github.com/achim-k/pi-telegram-modem-dooropener
[INFO] finished tweaking git repo https://github.com/achim-k/pi-telegram-modem-dooropener
[INFO] tweaked toml for git repo https://github.com/achim-k/pi-telegram-modem-dooropener written to /workspace/builds/worker-1-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/achim-k/pi-telegram-modem-dooropener 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" "+2399cef65c47f346b5fa9df51f48df0acd4a9d85" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[ERROR] error running command: no output for 300 seconds
[INFO] checking achim-k/pi-telegram-modem-dooropener against try#2399cef65c47f346b5fa9df51f48df0acd4a9d85 for pr-114571-3
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fachim-k%2Fpi-telegram-modem-dooropener" "/workspace/builds/worker-1-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/achim-k/pi-telegram-modem-dooropener on toolchain 2399cef65c47f346b5fa9df51f48df0acd4a9d85
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+2399cef65c47f346b5fa9df51f48df0acd4a9d85" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] removed /workspace/builds/worker-1-tc2/source/.cargo/config.toml
[INFO] started tweaking git repo https://github.com/achim-k/pi-telegram-modem-dooropener
[INFO] finished tweaking git repo https://github.com/achim-k/pi-telegram-modem-dooropener
[INFO] tweaked toml for git repo https://github.com/achim-k/pi-telegram-modem-dooropener written to /workspace/builds/worker-1-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/achim-k/pi-telegram-modem-dooropener 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" "+2399cef65c47f346b5fa9df51f48df0acd4a9d85" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[ERROR] error running command: no output for 300 seconds
[INFO] checking achim-k/pi-telegram-modem-dooropener against try#2399cef65c47f346b5fa9df51f48df0acd4a9d85 for pr-114571-3
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fachim-k%2Fpi-telegram-modem-dooropener" "/workspace/builds/worker-1-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/achim-k/pi-telegram-modem-dooropener on toolchain 2399cef65c47f346b5fa9df51f48df0acd4a9d85
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+2399cef65c47f346b5fa9df51f48df0acd4a9d85" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] removed /workspace/builds/worker-1-tc2/source/.cargo/config.toml
[INFO] started tweaking git repo https://github.com/achim-k/pi-telegram-modem-dooropener
[INFO] finished tweaking git repo https://github.com/achim-k/pi-telegram-modem-dooropener
[INFO] tweaked toml for git repo https://github.com/achim-k/pi-telegram-modem-dooropener written to /workspace/builds/worker-1-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/achim-k/pi-telegram-modem-dooropener 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" "+2399cef65c47f346b5fa9df51f48df0acd4a9d85" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[ERROR] error running command: no output for 300 seconds
[INFO] checking achim-k/pi-telegram-modem-dooropener against try#2399cef65c47f346b5fa9df51f48df0acd4a9d85 for pr-114571-3
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fachim-k%2Fpi-telegram-modem-dooropener" "/workspace/builds/worker-1-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/achim-k/pi-telegram-modem-dooropener on toolchain 2399cef65c47f346b5fa9df51f48df0acd4a9d85
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+2399cef65c47f346b5fa9df51f48df0acd4a9d85" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] removed /workspace/builds/worker-1-tc2/source/.cargo/config.toml
[INFO] started tweaking git repo https://github.com/achim-k/pi-telegram-modem-dooropener
[INFO] finished tweaking git repo https://github.com/achim-k/pi-telegram-modem-dooropener
[INFO] tweaked toml for git repo https://github.com/achim-k/pi-telegram-modem-dooropener written to /workspace/builds/worker-1-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/achim-k/pi-telegram-modem-dooropener 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" "+2399cef65c47f346b5fa9df51f48df0acd4a9d85" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[ERROR] error running command: no output for 300 seconds
[ERROR] this task or one of its parent failed!
[ERROR] no output for 300 seconds
[ERROR] note: run with `RUST_BACKTRACE=1` to display a backtrace.