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fmt: segfaults (panic) on "hello world" with -linkshared #64925

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stevenengler opened this issue Jan 2, 2024 · 3 comments
Closed

fmt: segfaults (panic) on "hello world" with -linkshared #64925

stevenengler opened this issue Jan 2, 2024 · 3 comments
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NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one.

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@stevenengler
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Go version

go version go1.21.5 linux/amd64

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

GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/root/.cache/go-build'
GOENV='/root/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/root/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/root/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='go1.21.5'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='gcc'
CXX='g++'
CGO_ENABLED='1'
GOMOD='/dev/null'
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-build4191319309=/tmp/go-build -gno-record-gcc-switches'

What did you do?

When compiling a "hello world" example when using the -linkshared flag, the fmt.Println("hello") segfaults. The following example works on earlier versions of Go. The following are steps to reproduce:

sudo docker run -it --rm ubuntu:22.04

In the container:

apt update
apt upgrade -y
apt install -y tar curl build-essential
cd /tmp/
curl https://dl.google.com/go/go1.21.5.linux-amd64.tar.gz > go.tar.gz
tar -C /usr/local -xzf go.tar.gz
PATH=$PATH:/usr/local/go/bin
go install -buildmode=shared -linkshared std
cat <<EOF >> foo.go
package main

import (
    "fmt"
)

func main() {
    fmt.Println("hello")
}
EOF
go build -linkshared -o foo foo.go
./foo

What did you expect to see?

hello

What did you see instead?

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x7f7fbe0038b3]

goroutine 1 [running]:
os.(*File).write(...)
	/usr/local/go/src/os/file_posix.go:46
os.(*File).Write(0x0, {0xc0003a6000?, 0x6, 0x7f7fbdf0f145?})
	/usr/local/go/src/os/file.go:183 +0x53
fmt.Fprintln({0x5607de781b48, 0x0}, {0xc000360f20, 0x1, 0x1})
	/usr/local/go/src/fmt/print.go:305 +0x6f
fmt.Println(...)
	/usr/local/go/src/fmt/print.go:314
@stevenengler
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A workaround for the example above is to use an unnecessary os import:

import (
    _ "os"
    "fmt"
)
$ go build -linkshared -o foo foo.go
$ ./foo
hello

I don't know much about Go so I don't know if this is expected or not.

@stevenengler stevenengler mentioned this issue Jan 2, 2024
Closed
@mauri870 mauri870 added the NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. label Jan 2, 2024
@mauri870
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mauri870 commented Jan 2, 2024

/cc @golang/compiler

@seankhliao
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fixed on tip / 1.22rc1

@seankhliao seankhliao closed this as not planned Won't fix, can't repro, duplicate, stale Jan 2, 2024
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@stevenengler @mauri870 @seankhliao