x/build/cmd/relui: go1.21.0.linux-armv6l built with GOARM=7

[ksgriggs]

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

$ go version
1.21.0

Does this issue reproduce with the latest release?

Yes

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

Linux raspberrypi 6.1.21+ #1642 Mon Apr 3 17:19:14 BST 2023 armv6l GNU/Linux

Raspbian GNU/Linux 11 (bullseye)

go env Output

$ go env
Illegal instruction

What did you do?

Installed go 1.21.0 onto two different Raspberry Pi zero w and get the same illegal instruction output when running go.
I installed https://go.dev/dl/go1.21.0.linux-armv6l.tar.gz. Version 1.20.7 works.

1. rm -rf /usr/local/go && tar -C /usr/local -xzf go1.21.0.linux-armv6l.tar.gz
2. go version

What did you expect to see?

When running "go version" I expected to see the go version output and not "illegal instruction"

What did you see instead?

illegal instruction

[seankhliao]

seems like it was built with GOARM=7 instead of 6

go: go1.21.0
	path	cmd/go
	build	-buildmode=exe
	build	-compiler=gc
	build	-gcflags=cmd/...=-dwarf=false
	build	-trimpath=true
	build	DefaultGODEBUG=panicnil=1
	build	CGO_ENABLED=0
	build	GOARCH=arm
	build	GOOS=linux
	build	GOARM=7

The arm64 artifact by contrast has no explicit GOARM set

go: go1.21.0
	path	cmd/go
	build	-buildmode=exe
	build	-compiler=gc
	build	-gcflags=cmd/...=-dwarf=false
	build	-trimpath=true
	build	DefaultGODEBUG=panicnil=1
	build	CGO_ENABLED=0
	build	GOARCH=arm64
	build	GOOS=linux

cc @golang/release

[dmitshur]

Indeed, thanks for reporting.

It was set to GOARM=6 in 1.20 and older because the release target used the linux-arm-aws builder, and that builder has GOARM=6 in its environment. For Go 1.21.0, it's built on a linux-amd64 builder via make.bash -distpack, and GOARM wasn't set in the release target's environment explicitly, so it ended up defaulting to 7 in make.bash.

$ go version -m ./go1.21.0/bin/go | tail -n 3
	build	GOARCH=arm
	build	GOOS=linux
	build	GOARM=7
$ go version -m ./go1.20.7/bin/go | tail -n 3
	build	GOARCH=arm
	build	GOOS=linux
	build	GOARM=6

The arm64 targets aren't affected because GOARM is for arm (32-bit) only and GOARM64 hasn't been added yet (see #60905 and #62129).

[gopherbot]

Change https://go.dev/cl/521555 mentions this issue: internal/releasetargets: set GOARM=6 for linux-armv6l