[INFO] cloning repository https://github.com/nitros12/pyo3_queue_test_eventfd
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/nitros12/pyo3_queue_test_eventfd" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnitros12%2Fpyo3_queue_test_eventfd", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnitros12%2Fpyo3_queue_test_eventfd'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 5649db1871ed7acddf907a6251407ef4dbc56072
[INFO] testing nitros12/pyo3_queue_test_eventfd against 1.49.0 for beta-1.50-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnitros12%2Fpyo3_queue_test_eventfd" "/workspace/builds/worker-6/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/nitros12/pyo3_queue_test_eventfd on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/nitros12/pyo3_queue_test_eventfd
[INFO] finished tweaking git repo https://github.com/nitros12/pyo3_queue_test_eventfd
[INFO] tweaked toml for git repo https://github.com/nitros12/pyo3_queue_test_eventfd written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate git repo https://github.com/nitros12/pyo3_queue_test_eventfd already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 252e6b5872f13ab4cd7b33751cab9018b24d5d4d20adce9bc344bc8735bba5ca
[INFO] running `Command { std: "docker" "start" "-a" "252e6b5872f13ab4cd7b33751cab9018b24d5d4d20adce9bc344bc8735bba5ca", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "252e6b5872f13ab4cd7b33751cab9018b24d5d4d20adce9bc344bc8735bba5ca", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "252e6b5872f13ab4cd7b33751cab9018b24d5d4d20adce9bc344bc8735bba5ca", kill_on_drop: false }`
[INFO] [stdout] 252e6b5872f13ab4cd7b33751cab9018b24d5d4d20adce9bc344bc8735bba5ca
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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=warn" "-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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] dead413e25caf6cc63f21edc039b297c293ce531ee9dba7a863a65a0bf35f9f2
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "dead413e25caf6cc63f21edc039b297c293ce531ee9dba7a863a65a0bf35f9f2", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.48
[INFO] [stderr]    Compiling unindent v0.1.7
[INFO] [stderr]    Compiling inventory v0.1.9
[INFO] [stderr]    Compiling pyo3 v0.12.3
[INFO] [stderr]    Compiling strum v0.13.0
[INFO] [stderr]    Compiling likely v0.1.0
[INFO] [stderr]    Compiling errno v0.2.7
[INFO] [stderr]    Compiling tokio v0.3.2
[INFO] [stderr]    Compiling strum_macros v0.13.0
[INFO] [stderr]    Compiling file-descriptors v0.9.1
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/file-descriptors-0.9.1/src/lib.rs:10:1
[INFO] [stdout]    |
[INFO] [stdout] 10 | #![feature(core_intrinsics)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/file-descriptors-0.9.1/src/lib.rs:11:1
[INFO] [stdout]    |
[INFO] [stdout] 11 | #![feature(read_initializer)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `file-descriptors`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "dead413e25caf6cc63f21edc039b297c293ce531ee9dba7a863a65a0bf35f9f2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "dead413e25caf6cc63f21edc039b297c293ce531ee9dba7a863a65a0bf35f9f2", kill_on_drop: false }`
[INFO] [stdout] dead413e25caf6cc63f21edc039b297c293ce531ee9dba7a863a65a0bf35f9f2