GOARCH=arm64 go generate is failing on x86_64

[SRodi]

Issue

go generate for GOARCH=arm64 is failing

❯ GOARCH=arm64 go generate ./pkg/plugin/...;                            
fork/exec /tmp/go-build4230987009/b001/exe/mockgen: exec format error
pkg/plugin/api/types.go:13: running "go": exit status 1
fork/exec /tmp/go-build1479343241/b001/exe/mockgen: exec format error
pkg/plugin/common/common_linux.go:20: running "go": exit status 1
fork/exec /tmp/go-build3235587832/b001/exe/bpf2go: exec format error
pkg/plugin/conntrack/conntrack_linux.go:22: running "go": exit status 1
fork/exec /tmp/go-build7630523/b001/exe/bpf2go: exec format error
pkg/plugin/dropreason/dropreason_linux.go:36: running "go": exit status 1
fork/exec /tmp/go-build2414488603/b001/exe/bpf2go: exec format error
pkg/plugin/filter/filter_map_linux.go:23: running "go": exit status 1
fork/exec /tmp/go-build1515059695/b001/exe/mockgen: exec format error
pkg/plugin/infiniband/types_linux.go:17: running "go": exit status 1
fork/exec /tmp/go-build2004312046/b001/exe/mockgen: exec format error
pkg/plugin/linuxutil/types_linux.go:16: running "go": exit status 1
fork/exec /tmp/go-build396399719/b001/exe/bpf2go: exec format error
pkg/plugin/packetforward/packetforward_linux.go:31: running "go": exit status 1
fork/exec /tmp/go-build309799770/b001/exe/bpf2go: exec format error
pkg/plugin/packetparser/packetparser_linux.go:52: running "go": exit status 1

Environment

❯ uname -a                 
Linux Simone 5.15.167.4-microsoft-standard-WSL2 #1 SMP Tue Nov 5 00:21:55 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

❯ go version                                      
go version go1.23.1 linux/amd64

❯ which clang
which llvm-strip
/usr/bin/clang
/usr/bin/llvm-strip

[timraymond]

Spoke with @SRodi offline about this. My working theory on the root cause of this is the re-entrant invocation of the Go toolchain with go generate. When GOARCH=arm64 go generate ./pkg/plugin/... happens, it invokes the go run github.com/x/y/z/bpf2go@master lines. This also receives GOARCH=arm64, and builds the arm64 version of bpf2go. It then tries to run it and fails because it's an amd64 system.

I don't think go generate was ever intended to be used with go run embedded in it. I think the solution will be to remove the go run parts. A workaround could be to go install the tools ahead of time.