[INFO] cloning repository https://github.com/chris-tomich/learning_rust_os
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/chris-tomich/learning_rust_os" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fchris-tomich%2Flearning_rust_os", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fchris-tomich%2Flearning_rust_os'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 4fa52d9b23779cf81e11d40d96e970f2ba88a27c
[INFO] testing chris-tomich/learning_rust_os against master#a77da2d454e6caa227a85b16410b95f93495e7e0 for pr-91031
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fchris-tomich%2Flearning_rust_os" "/workspace/builds/worker-7/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/chris-tomich/learning_rust_os on toolchain a77da2d454e6caa227a85b16410b95f93495e7e0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a77da2d454e6caa227a85b16410b95f93495e7e0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/chris-tomich/learning_rust_os
[INFO] finished tweaking git repo https://github.com/chris-tomich/learning_rust_os
[INFO] tweaked toml for git repo https://github.com/chris-tomich/learning_rust_os written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] crate git repo https://github.com/chris-tomich/learning_rust_os already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a77da2d454e6caa227a85b16410b95f93495e7e0" "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
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+a77da2d454e6caa227a85b16410b95f93495e7e0" "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] 63cef4266dd2b2c53ce33c8f7ae0a9385cfb0eede9f22dc090e75b2dbe885770
[INFO] running `Command { std: "docker" "start" "-a" "63cef4266dd2b2c53ce33c8f7ae0a9385cfb0eede9f22dc090e75b2dbe885770", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "63cef4266dd2b2c53ce33c8f7ae0a9385cfb0eede9f22dc090e75b2dbe885770", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "63cef4266dd2b2c53ce33c8f7ae0a9385cfb0eede9f22dc090e75b2dbe885770", kill_on_drop: false }`
[INFO] [stdout] 63cef4266dd2b2c53ce33c8f7ae0a9385cfb0eede9f22dc090e75b2dbe885770
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+a77da2d454e6caa227a85b16410b95f93495e7e0" "build" "--frozen" "--message-format=json", 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] 8bf4bdd85cbb81fb9884da81fd465d5a39aa5af483fb817c32d84e20df9fc4b9
[INFO] running `Command { std: "docker" "start" "-a" "8bf4bdd85cbb81fb9884da81fd465d5a39aa5af483fb817c32d84e20df9fc4b9", kill_on_drop: false }`
[INFO] [stderr]    Compiling learning_rust_os v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error: linking with `cc` failed: exit status: 1
[INFO] [stdout]   |
[INFO] [stdout]   = note: "cc" "-m64" "/opt/rustwide/target/debug/deps/learning_rust_os-9382dde49d21a29f.learning_rust_os.275777fa-cgu.0.rcgu.o" "-Wl,--as-needed" "-L" "/opt/rustwide/target/debug/deps" "-L" "/opt/rustwide/rustup-home/toolchains/a77da2d454e6caa227a85b16410b95f93495e7e0/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-Wl,-Bstatic" "/opt/rustwide/rustup-home/toolchains/a77da2d454e6caa227a85b16410b95f93495e7e0/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_core-2a6a2797f7a73818.rlib" "/opt/rustwide/rustup-home/toolchains/a77da2d454e6caa227a85b16410b95f93495e7e0/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcore-0e3656b1fda5fd7b.rlib" "/opt/rustwide/rustup-home/toolchains/a77da2d454e6caa227a85b16410b95f93495e7e0/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcompiler_builtins-13b419dfbcf9c1f8.rlib" "-Wl,-Bdynamic" "-Wl,--eh-frame-hdr" "-Wl,-znoexecstack" "-L" "/opt/rustwide/rustup-home/toolchains/a77da2d454e6caa227a85b16410b95f93495e7e0/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-o" "/opt/rustwide/target/debug/deps/learning_rust_os-9382dde49d21a29f" "-Wl,--gc-sections" "-pie" "-Wl,-zrelro,-znow" "-nodefaultlibs"
[INFO] [stdout]   = note: /usr/bin/ld: /opt/rustwide/target/debug/deps/learning_rust_os-9382dde49d21a29f.learning_rust_os.275777fa-cgu.0.rcgu.o: in function `_start':
[INFO] [stdout]           /opt/rustwide/workdir/src/main.rs:8: multiple definition of `_start'; /usr/lib/gcc/x86_64-linux-gnu/9/../../../x86_64-linux-gnu/Scrt1.o:(.text+0x0): first defined here
[INFO] [stdout]           /usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/9/../../../x86_64-linux-gnu/Scrt1.o: in function `_start':
[INFO] [stdout]           (.text+0x16): undefined reference to `__libc_csu_fini'
[INFO] [stdout]           /usr/bin/ld: (.text+0x1d): undefined reference to `__libc_csu_init'
[INFO] [stdout]           /usr/bin/ld: (.text+0x24): undefined reference to `main'
[INFO] [stdout]           /usr/bin/ld: (.text+0x2a): undefined reference to `__libc_start_main'
[INFO] [stdout]           collect2: error: ld returned 1 exit status
[INFO] [stdout]           
[INFO] [stdout]   = help: some `extern` functions couldn't be found; some native libraries may need to be installed or have their path specified
[INFO] [stdout]   = note: use the `-l` flag to specify native libraries to link
[INFO] [stdout]   = note: use the `cargo:rustc-link-lib` directive to specify the native libraries to link with Cargo (see https://doc.rust-lang.org/cargo/reference/build-scripts.html#cargorustc-link-libkindname)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `learning_rust_os` due to 2 previous errors
[INFO] running `Command { std: "docker" "inspect" "8bf4bdd85cbb81fb9884da81fd465d5a39aa5af483fb817c32d84e20df9fc4b9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8bf4bdd85cbb81fb9884da81fd465d5a39aa5af483fb817c32d84e20df9fc4b9", kill_on_drop: false }`
[INFO] [stdout] 8bf4bdd85cbb81fb9884da81fd465d5a39aa5af483fb817c32d84e20df9fc4b9