x/build: spurious cannot find package on plan9-arm

[bcmills]

#!watchflakes
post <- builder ~ `^plan9` && ` cannot find package`

go/src/runtime/cgocall.go:90:2: cannot find package "runtime/internal/sys" in:
	/boot/workdir/go/src/runtime/internal/sys
go tool dist: Failed: exit status: 'go 11148: 1'

greplogs -l -e '(?ms)\Aplan9.* cannot find package' --since=2022-01-01
2022-05-13T19:51:03-540f8c2/plan9-arm

Looks like probably a filesystem bug to me..?

(attn @golang/plan9)

[gopherbot]

Timed out in state WaitingForInfo. Closing.

(I am just a bot, though. Please speak up if this is a mistake or you have the requested information.)

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
post <- builder ~ `^plan9` && ` cannot find package`

2023-04-27 18:35 plan9-arm go@3a7806d3 (log)

encoding/json/decode.go:11:2: open /boot/workdir/go/src/encoding: '/boot/workdir' fossil/fossil: walk: newfid 0x756 in use
syscall/syscall_plan9.go:16:2: open /boot/cache/53/53c75b72a030ebef34c0d08e1066c74839c08459d75f806ec102bbe9b7f04977-d: '/boot/cache' fossil/fossil: walk: newfid 0x756 in use
os/env.go:10:2: open /boot/workdir/go/src/internal/testlog: '/boot/workdir' fossil/fossil: walk: newfid 0x756 in use
io/fs/glob.go:8:2: open /boot/cache/ce/cee56842bebd5c09089bec682ed727c38f518888bc1aac2370d4829698254e9d-d: '/boot/cache' fossil/fossil: walk: newfid 0x756 in use
encoding/json/decode.go:18:2: open /boot/workdir/go/src/unicode/utf16: '/boot/workdir' fossil/fossil: walk: newfid 0x756 in use
net/cgo_stub.go:9:8: open /boot/workdir/go/src/context: '/boot/workdir' fossil/fossil: walk: newfid 0x756 in use
text/template/exec.go:15:2: open /boot/workdir/go/src/text/template/parse: '/boot/workdir' fossil/fossil: walk: newfid 0x756 in use
log/log.go:20:2: open /boot/workdir/go/src/log/internal: '/boot/workdir' fossil/fossil: walk: newfid 0x756 in use
net/http/h2_bundle.go:25:2: open /boot/workdir/go/src/compress/gzip: '/boot/workdir' fossil/fossil: walk: newfid 0x756 in use
net/http/transport.go:15:2: open /boot/workdir/go/src/container/list: '/boot/workdir' fossil/fossil: walk: newfid 0x756 in use
...
crypto/x509/parser.go:28:2: cannot find package "vendor/golang.org/x/crypto/cryptobyte" in:
	/boot/workdir/go/src/vendor/golang.org/x/crypto/cryptobyte
crypto/tls/cipher_suites.go:22:2: open /boot/workdir/go/src/vendor/golang.org/x/crypto/chacha20poly1305: '/boot/workdir' fossil/fossil: walk: newfid 0x756 in use
vendor/golang.org/x/net/http/httpguts/httplex.go:12:2: cannot find package
net/http/transport.go:35:2: open /boot/cache/f6/f6628a404f378f265442dc6cdf2ac7587e020d259fd083c0c7651036d3a9a608-d: '/boot/cache' fossil/fossil: walk: newfid 0x756 in use
net/http/h2_bundle.go:52:2: open /boot/workdir/go/src/vendor/golang.org/x/net/http2/hpack: '/boot/workdir' fossil/fossil: walk: newfid 0x756 in use
net/http/fs.go:15:2: open /boot/workdir/go/src/mime: '/boot/workdir' fossil/fossil: walk: newfid 0x756 in use
net/http/clone.go:8:2: open /boot/cache/4e/4e66f4634b61734afdab72ac678b00c79ff7cda50f4a3eb1993cb136011610a0-d: '/boot/cache' fossil/fossil: walk: newfid 0x756 in use
net/http/transfer.go:14:2: open /boot/workdir/go/src/net/http/internal: '/boot/workdir' fossil/fossil: walk: newfid 0x756 in use
go tool dist: Failed: exit status: 'go 32492: 1'

— watchflakes

[millerresearch]

Duplicate of #46526 - the 'fid in use' message is the significant one, showing that it's an underlying filesystem error. I changed the message to 'newfid 0xNNN in use' to try to get more useful information, but diagnosis is still elusive. It's clearly a Plan 9 problem not a go problem.

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
post <- builder ~ `^plan9` && ` cannot find package`

2023-05-15 21:31 plan9-arm go@7213f2e7 (log)

cannot find package "." in:
	/boot/workdir/go/pkg/bootstrap/src/bootstrap/cmd/asm
cannot find package "." in:
	/boot/workdir/go/pkg/bootstrap/src/bootstrap/cmd/asm/internal/arch
cannot find package "." in:
	/boot/workdir/go/pkg/bootstrap/src/bootstrap/cmd/asm/internal/asm
../../../../src/cmd/asm/internal/flags/flags.go:9: open /boot/workdir/go/pkg/bootstrap/src/bootstrap/cmd/internal/obj: '/boot/workdir' fossil/fossil-9legacy: walk: newfid 0x464 in use
../../../../src/cmd/asm/internal/flags/flags.go:10: cannot find package "." in:
	/boot/workdir/go/pkg/bootstrap/src/bootstrap/cmd/internal/objabi
/boot/workdir/go1.4/src/os/exec.go:8:2: package errors is not in GOROOT (/boot/workdir/go1.4/src/errors)
...
open /boot/workdir/go/pkg/bootstrap/src/bootstrap/cmd/link/internal/loadxcoff: '/boot/workdir' fossil/fossil-9legacy: walk: newfid 0x464 in use
open /boot/workdir/go/pkg/bootstrap/src/bootstrap/cmd/link/internal/loong64: '/boot/workdir' fossil/fossil-9legacy: walk: newfid 0x464 in use
open /boot/workdir/go/pkg/bootstrap/src/bootstrap/cmd/link/internal/mips: '/boot/workdir' fossil/fossil-9legacy: walk: newfid 0x464 in use
open /boot/workdir/go/pkg/bootstrap/src/bootstrap/cmd/link/internal/mips64: '/boot/workdir' fossil/fossil-9legacy: walk: newfid 0x464 in use
open /boot/workdir/go/pkg/bootstrap/src/bootstrap/cmd/link/internal/ppc64: '/boot/workdir' fossil/fossil-9legacy: walk: newfid 0x464 in use
open /boot/workdir/go/pkg/bootstrap/src/bootstrap/cmd/link/internal/riscv64: '/boot/workdir' fossil/fossil-9legacy: walk: newfid 0x464 in use
open /boot/workdir/go/pkg/bootstrap/src/bootstrap/cmd/link/internal/s390x: '/boot/workdir' fossil/fossil-9legacy: walk: newfid 0x464 in use
open /boot/workdir/go/pkg/bootstrap/src/bootstrap/cmd/link/internal/sym: '/boot/workdir' fossil/fossil-9legacy: walk: newfid 0x464 in use
open /boot/workdir/go/pkg/bootstrap/src/bootstrap/cmd/link/internal/wasm: '/boot/workdir' fossil/fossil-9legacy: walk: newfid 0x464 in use
go tool dist: FAILED: /boot/workdir/go1.4/bin/go install -tags=math_big_pure_go compiler_bootstrap purego bootstrap/cmd/...: exit status: 'go 289: 1'

— watchflakes