runtime: printing multiple fatal errors may interleave messages #69447
Description
Go version
master and latest (1.23.1)
Output of go env in your module/workspace:
GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/home/grongor/.cache/go-build'
GOENV='/home/grongor/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/home/grongor/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/grongor/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.23.1'
GODEBUG=''
GOTELEMETRY='local'
GOTELEMETRYDIR='/home/grongor/.config/go/telemetry'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='gcc'
CXX='g++'
CGO_ENABLED='1'
GOMOD='/home/grongor/projects/grongor/go-fatal-race/go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build2941128308=/tmp/go-build -gno-record-gcc-switches'What did you do?
Runnable test: https://github.com/grongor/go-fatal-race
Playground: https://go.dev/play/p/YicJmPOpJ6E
What did you see happen?
fatal error: concurrent map writes
fatal error: concurrent map writes
goroutine 5 [running]:
main.main.func1()
Sometimes different malformations like this:
fatal error: fatal error: concurrent map writes
concurrent map writes
goroutine 7 [running]: ...
What did you expect to see?
single fatal error: concurrent map writes followed by a stacktrace