internal/fuzz: odr-violation error

[n-bes]

Go version

go1.22.2 linux/amd64

Output of go env in your module/workspace:

GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/root/.cache/go-build'
GOENV='/root/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='local'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.22.2'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='clang'
CXX='g++'
CGO_ENABLED='1'
GOMOD='/src/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 -fno-caret-diagnostics -Qunused-arguments -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build3964025102=/tmp/go-build -gno-record-gcc-switches'

What did you do?

I ran this code on MacBook M3-chip with Docker Desktop and used latest official docker images (debian / alpine).

func FuzzParser(f *testing.F) {
	f.Fuzz(func(t *testing.T, data string) {
	})
}

What did you see happen?

# go test -fuzz=Fuzz -asan .

==40621==The following global variable is not properly aligned.
==40621==This may happen if another global with the same name
==40621==resides in another non-instrumented module.
==40621==Or the global comes from a C file built w/o -fno-common.
==40621==In either case this is likely an ODR violation bug,
==40621==but AddressSanitizer can not provide more details.
=================================================================
==40621==ERROR: AddressSanitizer: odr-violation (0x000005fecce3):
  [1] size=0 'internal/fuzz._ecounters' /usr/local/go/src/internal/fuzz/coverage.go:106:13
  [2] size=0 'internal/fuzz._ecounters' /usr/local/go/src/internal/fuzz/coverage.go:106:13
These globals were registered at these points:
  [1]:
    #0 0x2aaaab3211b8 in __asan_register_globals ../../../../src/libsanitizer/asan/asan_globals.cpp:341
    #1 0x183858c  (/tmp/go-build3032263961/b001/scan.test+0x183858c)

  [2]:
    #0 0x2aaaab3211b8 in __asan_register_globals ../../../../src/libsanitizer/asan/asan_globals.cpp:341
    #1 0x183858c  (/tmp/go-build3032263961/b001/scan.test+0x183858c)

==40621==HINT: if you don't care about these errors you may set ASAN_OPTIONS=detect_odr_violation=0
SUMMARY: AddressSanitizer: odr-violation: global 'internal/fuzz._ecounters' at /usr/local/go/src/internal/fuzz/coverage.go:106:13
==40621==ABORTING

# go test -asan -fuzz=Fuzz .

==20374==The following global variable is not properly aligned.
==20374==This may happen if another global with the same name
==20374==resides in another non-instrumented module.
==20374==Or the global comes from a C file built w/o -fno-common.
==20374==In either case this is likely an ODR violation bug,
==20374==but AddressSanitizer can not provide more details.
=================================================================
==20374==ERROR: AddressSanitizer: odr-violation (0x000006b0c2c3):
  [1] size=0 'internal/fuzz._ecounters' /usr/local/go/src/internal/fuzz/coverage.go:106:13
  [2] size=0 'internal/fuzz._ecounters' /usr/local/go/src/internal/fuzz/coverage.go:106:13
These globals were registered at these points:
  [1]:
    #0 0x17ef29b  (/tmp/go-build585142908/b001/scan.test+0x17ef29b) (BuildId: 367c8411fdfbdc6ab6efe02464d6626ff04f1a3c)
    #1 0x191956c  (/tmp/go-build585142908/b001/scan.test+0x191956c) (BuildId: 367c8411fdfbdc6ab6efe02464d6626ff04f1a3c)

  [2]:
    #0 0x17ef29b  (/tmp/go-build585142908/b001/scan.test+0x17ef29b) (BuildId: 367c8411fdfbdc6ab6efe02464d6626ff04f1a3c)
    #1 0x191956c  (/tmp/go-build585142908/b001/scan.test+0x191956c) (BuildId: 367c8411fdfbdc6ab6efe02464d6626ff04f1a3c)

==20374==HINT: if you don't care about these errors you may set ASAN_OPTIONS=detect_odr_violation=0
SUMMARY: AddressSanitizer: odr-violation: global 'internal/fuzz._ecounters' at /usr/local/go/src/internal/fuzz/coverage.go:106:13
==20374==ABORTING
exit status 1

What did you expect to see?

I've tried to set ASAN_OPTIONS=detect_odr_violation=0 without success:

• before build
• after build
• testing.F.Setenv

[n-bes]

MRE:
go.mod:

module hello

go 1.22.2

main_test.go:

package hello

import (
	"testing"
	"unicode/utf8"
)

func Reverse(s string) string {
	b := []byte(s)
	for i, j := 0, len(b)-1; i < len(b)/2; i, j = i+1, j-1 {
		b[i], b[j] = b[j], b[i]
	}
	return string(b)
}

func FuzzReverse(f *testing.F) {
	testcases := []string{"Hello, world", " ", "!12345"}
	for _, tc := range testcases {
		f.Add(tc) // Use f.Add to provide a seed corpus
	}
	f.Fuzz(func(t *testing.T, orig string) {
		rev := Reverse(orig)
		doubleRev := Reverse(rev)
		if orig != doubleRev {
			t.Errorf("Before: %q, after: %q", orig, doubleRev)
		}
		if utf8.ValidString(orig) && !utf8.ValidString(rev) {
			t.Errorf("Reverse produced invalid UTF-8 string %q", rev)
		}
	})
}

docker run --rm -it -v $PWD:/src golang

[n-bes]

Still crashes

$ go version
go version go1.23.2 linux/amd64

$ cat /etc/os-release
PRETTY_NAME="Ubuntu 22.04.3 LTS"

package main

import (
        "path"
        "testing"
)

func FuzzPathClean(f *testing.F) {
        f.Fuzz(func(t *testing.T, data string) {
                res := path.Clean(data)

                t.Log("in:", data)
                t.Log("out:", res)
        })
}

$ go test -asan -fuzz=FuzzPathClean ./main_test.go

==199089==The following global variable is not properly aligned.
==199089==This may happen if another global with the same name
==199089==resides in another non-instrumented module.
==199089==Or the global comes from a C file built w/o -fno-common.
==199089==In either case this is likely an ODR violation bug,
==199089==but AddressSanitizer can not provide more details.
=================================================================
==199089==ERROR: AddressSanitizer: odr-violation (0x00000097588d):
  [1] size=0 'internal/fuzz._ecounters' /usr/local/go/src/internal/fuzz/coverage.go:104:13
  [2] size=0 'internal/fuzz._ecounters' /usr/local/go/src/internal/fuzz/coverage.go:104:13
These globals were registered at these points:
  [1]:
    #0 0x7f53f7a4b928 in __asan_register_globals ../../../../src/libsanitizer/asan/asan_globals.cpp:341
    #1 0x477f4c  (/tmp/go-build1051884221/b001/main.test+0x477f4c)

  [2]:
    #0 0x7f53f7a4b928 in __asan_register_globals ../../../../src/libsanitizer/asan/asan_globals.cpp:341
    #1 0x477f4c  (/tmp/go-build1051884221/b001/main.test+0x477f4c)

==199089==HINT: if you don't care about these errors you may set ASAN_OPTIONS=detect_odr_violation=0
SUMMARY: AddressSanitizer: odr-violation: global 'internal/fuzz._ecounters' at /usr/local/go/src/internal/fuzz/coverage.go:104:13
==199089==ABORTING
exit status 1
FAIL    command-line-arguments  0.014s

[randall77]

Looks like fuzz and asan are not playing nicely together. Asan is unhappy with us writing the counter array which tracks coverage.

fuzz and race play nicely together though. Not sure what the difference is.

Setting ASAN_OPTIONS=detect_odr_violation=0 doesn't seem to make the error go away, not sure why it is suggested.

This would be nice if it worked, but I'm not sure it ever did. Marking for 1.24 is case someone knows an easy fix for it.

[randall77]

@kyakdan

[gopherbot]

Change https://go.dev/cl/622477 mentions this issue: cmd/link: for asan align coverage counters to 8 bytes