[INFO] cloning repository https://github.com/tiqwab/xv6-rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/tiqwab/xv6-rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftiqwab%2Fxv6-rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftiqwab%2Fxv6-rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 525899393df10855a274ce0a9d4e5841aa032aeb
[INFO] checking tiqwab/xv6-rust against master#3aedcf06b73fc36feeebca3d579e1d2a6c40acc5 for pr-65819
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftiqwab%2Fxv6-rust" "/workspace/builds/worker-13/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-13/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/tiqwab/xv6-rust on toolchain 3aedcf06b73fc36feeebca3d579e1d2a6c40acc5
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+3aedcf06b73fc36feeebca3d579e1d2a6c40acc5" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/tiqwab/xv6-rust
[INFO] finished tweaking git repo https://github.com/tiqwab/xv6-rust
[INFO] tweaked toml for git repo https://github.com/tiqwab/xv6-rust written to /workspace/builds/worker-13/source/Cargo.toml
[INFO] crate git repo https://github.com/tiqwab/xv6-rust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+3aedcf06b73fc36feeebca3d579e1d2a6c40acc5" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/jobserver:/tmp/crater-runner-fifo:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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:c46a2d1a26fb48b37929c74ca49dd9409f2375a0a3bdb8fe07617f3ffccaa889" "/opt/rustwide/cargo-home/bin/cargo" "+3aedcf06b73fc36feeebca3d579e1d2a6c40acc5" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8b421cf88b17b3700f5d4fd78daf885ac7f5e18bfecac37e9033f5eaa0aaaf7d
[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" "8b421cf88b17b3700f5d4fd78daf885ac7f5e18bfecac37e9033f5eaa0aaaf7d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8b421cf88b17b3700f5d4fd78daf885ac7f5e18bfecac37e9033f5eaa0aaaf7d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8b421cf88b17b3700f5d4fd78daf885ac7f5e18bfecac37e9033f5eaa0aaaf7d", kill_on_drop: false }`
[INFO] [stdout] 8b421cf88b17b3700f5d4fd78daf885ac7f5e18bfecac37e9033f5eaa0aaaf7d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/jobserver:/tmp/crater-runner-fifo:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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" "RUSTUP_TOOLCHAIN=3aedcf06b73fc36feeebca3d579e1d2a6c40acc5" "-e" "RUSTFLAGS=--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" "rustops/crates-build-env@sha256:c46a2d1a26fb48b37929c74ca49dd9409f2375a0a3bdb8fe07617f3ffccaa889" "/tmp/crater-runner-fifo/jobserver-crater-fwd" "/opt/rustwide/cargo-home/bin/cargo" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 820b0824e644ca74b85c44d83d10fa94c7ca8a9e9f94161c6e8a7b0056755067
[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" "820b0824e644ca74b85c44d83d10fa94c7ca8a9e9f94161c6e8a7b0056755067", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Checking scopeguard v1.1.0
[INFO] [stderr]    Compiling cc v1.0.50
[INFO] [stderr]     Checking lock_api v0.3.4
[INFO] [stderr]     Checking spinning_top v0.1.0
[INFO] [stderr]     Checking linked_list_allocator v0.8.4
[INFO] [stdout] error[E0658]: mutable references are not allowed in constant functions
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/linked_list_allocator-0.8.4/src/hole.rs:18:23
[INFO] [stdout]    |
[INFO] [stdout] 18 |                 next: None,
[INFO] [stdout]    |                       ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
[INFO] [stdout]    = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0658`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `linked_list_allocator`
[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" "820b0824e644ca74b85c44d83d10fa94c7ca8a9e9f94161c6e8a7b0056755067", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "820b0824e644ca74b85c44d83d10fa94c7ca8a9e9f94161c6e8a7b0056755067", kill_on_drop: false }`
[INFO] [stdout] 820b0824e644ca74b85c44d83d10fa94c7ca8a9e9f94161c6e8a7b0056755067