Stage 2 test failure on master branch; windows linux subsystem

[Phlosioneer]

unix_sub@DevWindows ~/r/rust> ./x.py test src/libstd --test-args double_bind
Updating only changed submodules
Submodules updated in 0.36 seconds
    Finished dev [unoptimized] target(s) in 0.0 secs
Building stage0 std artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/divdc3.c:21:1: warning: conflicting types for built-in function ‘__divdc3’ [enabled by default]
warning:  __divdc3(double __a, double __b, double __c, double __d)
warning:  ^
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/divsc3.c:21:1: warning: conflicting types for built-in function ‘__divsc3’ [enabled by default]
warning:  __divsc3(float __a, float __b, float __c, float __d)
warning:  ^
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/divxc3.c:22:1: warning: conflicting types for built-in function ‘__divxc3’ [enabled by default]
warning:  __divxc3(long double __a, long double __b, long double __c, long double __d)
warning:  ^
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/muldc3.c:21:1: warning: conflicting types for built-in function ‘__muldc3’ [enabled by default]
warning:  __muldc3(double __a, double __b, double __c, double __d)
warning:  ^
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/mulsc3.c:21:1: warning: conflicting types for built-in function ‘__mulsc3’ [enabled by default]
warning:  __mulsc3(float __a, float __b, float __c, float __d)
warning:  ^
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/mulxc3.c:23:1: warning: conflicting types for built-in function ‘__mulxc3’ [enabled by default]
warning:  __mulxc3(long double __a, long double __b, long double __c, long double __d)
warning:  ^
    Finished release [optimized] target(s) in 0.2 secs
Copying stage0 std from stage0 (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu / x86_64-unknown-linux-gnu)
Building stage0 test artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
    Finished release [optimized] target(s) in 0.0 secs
Copying stage0 test from stage0 (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu / x86_64-unknown-linux-gnu)
Building stage0 compiler artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
    Finished release [optimized] target(s) in 0.11 secs
Copying stage0 rustc from stage0 (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu / x86_64-unknown-linux-gnu)
Building stage0 codegen artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu, llvm)
    Finished release [optimized] target(s) in 0.1 secs
Assembling stage1 compiler (x86_64-unknown-linux-gnu)
Building stage1 std artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/divdc3.c:21:1: warning: conflicting types for built-in function ‘__divdc3’ [enabled by default]
warning:  __divdc3(double __a, double __b, double __c, double __d)
warning:  ^
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/divsc3.c:21:1: warning: conflicting types for built-in function ‘__divsc3’ [enabled by default]
warning:  __divsc3(float __a, float __b, float __c, float __d)
warning:  ^
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/divxc3.c:22:1: warning: conflicting types for built-in function ‘__divxc3’ [enabled by default]
warning:  __divxc3(long double __a, long double __b, long double __c, long double __d)
warning:  ^
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/muldc3.c:21:1: warning: conflicting types for built-in function ‘__muldc3’ [enabled by default]
warning:  __muldc3(double __a, double __b, double __c, double __d)
warning:  ^
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/mulsc3.c:21:1: warning: conflicting types for built-in function ‘__mulsc3’ [enabled by default]
warning:  __mulsc3(float __a, float __b, float __c, float __d)
warning:  ^
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/mulxc3.c:23:1: warning: conflicting types for built-in function ‘__mulxc3’ [enabled by default]
warning:  __mulxc3(long double __a, long double __b, long double __c, long double __d)
warning:  ^
    Finished release [optimized] target(s) in 0.2 secs
Copying stage1 std from stage1 (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu / x86_64-unknown-linux-gnu)
Building stage1 test artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
    Finished release [optimized] target(s) in 0.1 secs
Copying stage1 test from stage1 (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu / x86_64-unknown-linux-gnu)
Building stage1 compiler artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
    Finished release [optimized] target(s) in 0.2 secs
Copying stage1 rustc from stage1 (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu / x86_64-unknown-linux-gnu)
Building stage1 codegen artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu, llvm)
    Finished release [optimized] target(s) in 0.1 secs
Assembling stage2 compiler (x86_64-unknown-linux-gnu)
Uplifting stage1 std (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
Copying stage2 std from stage1 (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu / x86_64-unknown-linux-gnu)
Uplifting stage1 test (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
Copying stage2 test from stage1 (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu / x86_64-unknown-linux-gnu)
Uplifting stage1 rustc (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
Copying stage2 rustc from stage1 (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu / x86_64-unknown-linux-gnu)
Building rustdoc for stage2 (x86_64-unknown-linux-gnu)
    Finished release [optimized] target(s) in 0.1 secs
Testing std stage1 (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/divdc3.c:21:1: warning: conflicting types for built-in function ‘__divdc3’ [enabled by default]
warning:  __divdc3(double __a, double __b, double __c, double __d)
warning:  ^
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/divsc3.c:21:1: warning: conflicting types for built-in function ‘__divsc3’ [enabled by default]
warning:  __divsc3(float __a, float __b, float __c, float __d)
warning:  ^
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/divxc3.c:22:1: warning: conflicting types for built-in function ‘__divxc3’ [enabled by default]
warning:  __divxc3(long double __a, long double __b, long double __c, long double __d)
warning:  ^
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/muldc3.c:21:1: warning: conflicting types for built-in function ‘__muldc3’ [enabled by default]
warning:  __muldc3(double __a, double __b, double __c, double __d)
warning:  ^
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/mulsc3.c:21:1: warning: conflicting types for built-in function ‘__mulsc3’ [enabled by default]
warning:  __mulsc3(float __a, float __b, float __c, float __d)
warning:  ^
warning: ../../libcompiler_builtins/compiler-rt/lib/builtins/mulxc3.c:23:1: warning: conflicting types for built-in function ‘__mulxc3’ [enabled by default]
warning:  __mulxc3(long double __a, long double __b, long double __c, long double __d)
warning:  ^
    Finished release [optimized] target(s) in 0.3 secs
     Running build/x86_64-unknown-linux-gnu/stage1-std/x86_64-unknown-linux-gnu/release/deps/std-879e2a6b0cfef1d1

running 1 test
thread '<unnamed>' panicked at 'explicit panic', libstd/net/tcp.rs:1199:27
note: Run with `RUST_BACKTRACE=1` for a backtrace.
test net::tcp::tests::double_bind ... FAILED

failures:

failures:
    net::tcp::tests::double_bind

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 769 filtered out

error: test failed, to rerun pass '--lib'


command did not execute successfully: "/home/unix_sub/rust/rust/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "test" "--target" "x86_64-unknown-linux-gnu" "-j" "4" "--release" "--features" "panic-unwind jemalloc backtrace" "--manifest-path" "/home/unix_sub/rust/rust/src/libstd/Cargo.toml" "-p" "std" "--" "double_bind"
expected success, got: exit code: 101


failed to run: /home/unix_sub/rust/rust/build/bootstrap/debug/bootstrap test src/libstd --test-args double_bind
Build completed unsuccessfully in 0:00:18

I've never had issues doing a full compile and test of rust before. The windows linux subsystem should be equivalent to ubuntu for most intents and purposes, as far as I know.

Here's my version:

unix_sub@DevWindows ~/r/rust> uname -a
Linux DevWindows 4.4.0-43-Microsoft #1-Microsoft Wed Dec 31 14:42:53 PST 2014 x86_64 x86_64 x86_64 GNU/Linux

This technically isn't on master branch; but the only difference between master and my current working branch is a few ignored tests (#49366 ):

commit 559b57bf6449d1872d797ebe04a97024b0c999b2
Author: Phlosioneer <mattmdrr2@gmail.com>
Date:   Sun Mar 25 17:06:38 2018 -0400

    Ignore proc macro stage 1 tests

    A few tests related to proc-macros fail when performing stage-1
    testing. This PR adds // ignore-stage1 to them, along with a FIXME.

    Original issue: #49352

    This should (hopefully) be fixed when #49219 is merged.

commit 77e2bcb613c58ed2aeb86fdb07f470440f94f205
Merge: f5631d9 4eff4d9
Author: bors <bors@rust-lang.org>
Date:   Sun Mar 25 00:02:48 2018 +0000

    Auto merge of #49141 - gnzlbg:simd_select, r=alexcrichton

    adds simd_select intrinsic

    The select SIMD intrinsic is used to select elements from two SIMD vectors using a mask:

    ```rust
    let mask = b8x4::new(true, false, false, true);
    let a = f32x4::new(1., 2., 3., 4.);
    let b = f32x4::new(5., 6., 7., 8.);
    assert_eq!(simd_select(mask, a, b), f32x4::new(1., 6., 7., 4.));
    ```

    The number of lanes between the mask and the vectors must match, but the vector width of the mask do

    Note: this intrinsic will be exposed via `std::simd`'s vector masks - users are not expected to use

commit f5631d9ac7745dd6eaea2bc6c236d5f8e54e9a18
Merge: b4aa80d 297a6e5
Author: bors <bors@rust-lang.org>
Date:   Sat Mar 24 18:58:12 2018 +0000

    Auto merge of #49337 - kennytm:rollup, r=kennytm

    Rollup of 21 pull requests

    - Successful merges: #49046, #49076, #49089, #49120, #49121, #49122, #49162, #49193, #49194, #49203,
unix_sub@DevWindows ~/r/rust> git status
On branch 49352-proc-macro-test-failure
nothing to commit, working directory clean

[Phlosioneer]

Can confirm that this still happens on master branch as-is, and with the newest commits.

[cuviper]

The windows linux subsystem should be equivalent to ubuntu for most intents and purposes, as far as I know.

In theory, sure, but it's quite possible that Microsoft has not matched Linux behavior here.

[Phlosioneer]

I'm just going to close this, then. I wanted to make sure that it was just me, and not a known issue or something.

[cuviper]

FWIW, I wasn't trying to be dismissive -- just pointing out the possibility that the bug could be elsewhere. But anyway, I extracted that test to try it more easily:
https://play.rust-lang.org/?gist=4e595640c43d9dd52d3590cd34f26ebc&version=stable

This succeeds on the playground and on Fedora (4.15.10-300.fc27.x86_64), but fails on WSL+Debian (4.4.0-43-Microsoft). Maybe you could report it to https://github.com/Microsoft/WSL?

[Phlosioneer]

Thanks for the reply, but I didn't intend for this to be treated as a long-living issue.

[ssomers]

I'm new to Rust, but I'm getting the impression that Rust is to blame here. When I further simplify cuviper's code on playground, it's finally clear to me that the test case asserts that:

1. the system doesn't support double binding to TCP ports (the explicit panic reported here)
2. if the system doesn't support double binding, it reports an attempt to double bind in a decent way

Why the first point? I don't know anything about multiple binding, but I'm open to the idea. On WSL, the test code reports two different file descriptors and I assume (probably will test later) that both will get the same data that gets sent to the port. Any particular reason why Rust wouldn't like that?

[ssomers]

On closer inspection, there are reasons to like and dislike multiple binding (as illustrated in the introduction of SO_REUSEPORT). The reason multiple binding succeeds here is because TcpListener.bind in libstd/sys_common/net.rs sets the SO_REUSEADDR socket option. What this is supposed to do, you can have your pick:

• The comment in the Rust code says "to quickly rebind a socket, without needing to wait for the OS to clean up the previous one"
• The author of SO_REUSEPORT in Linux suggests that SO_REUSEADDR allows freely sharing (and hijacking) the port for UDP (so not TCP)
• The udp_bind implementation of lwIP seems to do the same as SO_REUSEPORT does, for UDP only
• Plenty of choice on stackoverflow
• Windows documentation on the matter suggest a lot more sharing and the behavior exhibited by the test here.

Probably for the latter, SO_REUSEADDR is not applied on Windows through if !cfg!(windows). But WSL is not Windows: in my WSL environment, rustc --print cfg lists:

target_arch="x86_64"
target_endian="little"
target_env="gnu"
target_family="unix"
target_feature="fxsr"
target_feature="sse"
target_feature="sse2"
target_os="linux"
target_pointer_width="64"
target_vendor="unknown"

I see no way to tune the if !cfg!(windows) to cover WSL as well.