GOEXPERIMENT=greenteagc cause panic with GOTOOLCHAIN=go1.25.0 (without installing go1.25.0)

[ukai]

Go version

go version go1.24.6 linux/amd64

Output of go env in your module/workspace:

AR='ar'                                                                         
CC='gcc'          
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'                                                           
CGO_ENABLED='1'                                                                 
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g' 
CXX='g++'   
GCCGO='gccgo'                           
GO111MODULE=''
GOAMD64='v1'                                                                    
GOARCH='amd64'                                                                 
GOAUTH='netrc'  
GOBIN=''                                
GOCACHE='/usr/local/google/home/ukai/.cache/go-build'
GOCACHEPROG=''                                                                  
GODEBUG='' 
GOENV='/usr/local/google/home/ukai/.config/go/env'
GOEXE=''                                                                        
GOEXPERIMENT=''                                                                 
GOFIPS140='off'
GOFLAGS=''         
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build395653373=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'                                                              
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/usr/local/google/home/ukai/src/infra/infra/go/src/infra/go.mod'
GOMODCACHE='/usr/local/google/home/ukai/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/usr/local/google/home/ukai/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/google/home/ukai/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.24.6.linux-amd64'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/usr/local/google/home/ukai/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/google/home/ukai/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.24.6.linux-amd64/pkg/tool/linux_amd64' 
GOVCS=''
GOVERSION='go1.24.6' 
GOWORK=''
PKG_CONFIG='pkg-config'

What did you do?

Try greenteagc (#73581) by

 % GOTOOLCHAIN=go1.25.0 GOEXPERIMENT=greenteagc go install ./...              

What did you see happen?

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x3 pc=0x81a081]          
                                        
goroutine 1 [running]:                                                          
cmd/go/internal/fips140.Init()                                                  
        cmd/go/internal/fips140/fips140.go:117 +0x101                           
cmd/go/internal/modload.Init()                                                  
        cmd/go/internal/modload/init.go:419 +0x33                               
cmd/go/internal/toolchain.Exec({0xc00002a0e4, 0x8})                             
        cmd/go/internal/toolchain/select.go:356 +0x3fc                          
cmd/go/internal/toolchain.Select()                                              
        cmd/go/internal/toolchain/select.go:284 +0x11a5        
main.main()                                                                             
         cmd/go/main.go:107 +0x4f  

What did you expect to see?

no panic.

note that after install go1.25.0, no panic.

 % go install golang.org/dl/go1.25.0@latest                                     
go: downloading golang.org/dl v0.0.0-20250812204734-236a62c85c37   
% go1.25.0 download                                                            
Downloaded   0.0% (   16384 / 59659213 bytes) ...                               
Downloaded 100.0% (59659213 / 59659213 bytes)
Unpacking /usr/local/google/home/ukai/sdk/go1.25.0/go1.25.0.linux-amd64.tar.gz .
..                                                                              
Success. You may now run 'go1.25.0' 
% GOTOOLCHAIN=go1.25.0 GOEXPERIMENT=greenteagc go install ./...
%

[gabyhelp]

Related Issues

• cmd/go: crash on unknown GOEXPERIMENT during toolchain selection #74111 (closed)
• panic: runtime error: invalid memory address or nil pointer dereference: cmd/go/internal/fips140/fips140.go:117 #75027 (closed)
• cmd/go: go tool panic when GOEXPERIMENT=jsonv2 #74862 (closed)
• x/tools/go/packages, go/ast: NewPackage causes SIGSEGV #37202 (closed)
• cmd/go, encoding/json/v2: setting GOEXPERIMENT=jsonv2 causes "go env -json" to crash #75018 (closed)
• gopls SEGV fault on startup. #70271 (closed)
• cmd/go: panic when building a `main` package in GOPATH mode when a go.work file exists #58767 (closed)
• cmd/compile: invalid memory address or nil pointer dereference in gc.convlit1 #35621 (closed)
• cmd/go: go build panics with empty old build constraints #44487 (closed)
• latest goimports panicing #39864 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}