go: cmd/link: TestFallocate fallocate_test error

What version of Go are you using (go version)?

$ go version
go version go1.12.9 darwin/amd64

Does this issue reproduce with the latest release?

no

What operating system and processor architecture are you using (go env)?

$ go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/rehack/Library/Caches/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/rehack/go"
GOPROXY=""
GORACE=""
GOROOT="/usr/local/webserver/go"
GOTMPDIR=""
GOTOOLDIR="/usr/local/webserver/go/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/1x/wz0y29vj6wg9frw1vcwb8sl40000gn/T/go-build191766201=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

Compile Go from source go1.15.src

➜  src ./all.bash

What did you expect to see?

No FAIL

What did you see instead?

ok      cmd/go/internal/renameio        0.505s
ok      cmd/go/internal/search  0.017s
ok      cmd/go/internal/test    0.029s
ok      cmd/go/internal/txtar   0.017s
ok      cmd/go/internal/web     0.022s
ok      cmd/go/internal/work    0.027s
ok      cmd/gofmt       0.046s
ok      cmd/internal/buildid    0.258s
ok      cmd/internal/dwarf      0.019s
ok      cmd/internal/edit       0.015s
ok      cmd/internal/goobj      0.863s
ok      cmd/internal/goobj2     0.015s
ok      cmd/internal/moddeps    1.456s
ok      cmd/internal/obj        0.016s
ok      cmd/internal/obj/arm64  0.131s
ok      cmd/internal/obj/ppc64  0.100s
ok      cmd/internal/obj/riscv  0.096s
ok      cmd/internal/obj/x86    10.811s
ok      cmd/internal/objabi     0.015s
ok      cmd/internal/src        0.016s
ok      cmd/internal/test2json  0.091s
ok      cmd/link        24.156s
ok      cmd/link/internal/benchmark     0.016s
--- FAIL: TestFallocate (0.01s)
    fallocate_test.go:61: unexpected disk usage: got 2040 blocks, want 2048
    fallocate_test.go:61: unexpected disk usage: got 6136 blocks, want 6144
FAIL
FAIL    cmd/link/internal/ld    13.383s
ok      cmd/link/internal/loader        0.034s
ok      cmd/link/internal/sym   0.016s
ok      cmd/nm  7.003s
ok      cmd/objdump     6.613s
ok      cmd/oldlink/internal/sym        0.016s
ok      cmd/pack        3.216s
ok      cmd/trace       0.080s
ok      cmd/vet 15.012s
FAIL
go tool dist: Failed: exit status 1