import/path: getting panic: d.nx != 0 when call md5.Sum in goroutines

[maxakeheomax]

Go version

go1.23

Output of go env in your module/workspace:

GO111MODULE='on'
GOARCH='arm64'
GOBIN='/Users/boldyrev/go/bin'
GOCACHE='/Users/boldyrev/Library/Caches/go-build'
GOENV='/Users/boldyrev/Library/Application Support/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='arm64'
GOHOSTOS='darwin'
GOINSECURE='gitlab.com'
GOMODCACHE='/Users/boldyrev/go/pkg/mod'
GONOPROXY='none'
GONOSUMDB='stash.tutu.ru,'
GOOS='darwin'
GOPATH='/Users/boldyrev/go'
GOPRIVATE='stash.tutu.ru,'
GOPROXY='http://goproxy.tutu.ru'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/darwin_arm64'
GOVCS=''
GOVERSION='go1.23.2'
GODEBUG=''
GOTELEMETRY='local'
GOTELEMETRYDIR='/Users/boldyrev/Library/Application Support/go/telemetry'
GCCGO='gccgo'
GOARM64='v8.0'
AR='ar'
CC='clang'
CXX='clang++'
CGO_ENABLED='1'
GOMOD='/Users/boldyrev/Desktop/Projects.tmp/broker/br-accounts/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 -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/var/folders/5t/1r88rzyj1s10t97_sx_k6l140000gp/T/go-build1432854356=/tmp/go-build -gno-record-gcc-switches -fno-common'

What did you do?

I use md5 generation for getting hashes for business segments. In production I have several goroutines for this.
https://go.dev/play/p/4V9wMX0xO-w

After small optimization:

func (h *Hasher) initHasher() {
	if h.hshr == nil {
		h.hshr = md5.New()

		return
	}

	h.hshr.Reset()
}

I start getting panics. If I return making md5.New() each time before getting .Sum(nil) — it works fine.

What did you see happen?

Im getting panics when asynchronously trying to calculate hashes.

What did you expect to see?

I expecting to see a working async hash generation using .Reset() function before calling .Sum() or explanation why it is not working :)

[seankhliao]

sounds like a race condition in your code

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For questions please refer to https://github.com/golang/go/wiki/Questions

[gabyhelp]

Related Issues

• crypto/md5: on 32-bit platforms, panic trying to Sum after a large amount of data hashed #29545 (closed)
• testing: integer divide by zero in predictN #70709 (closed)
• encoding/binary: panic when Write a nil. #60814 (closed)
• runtime/metrics: example panics when histogram has no counts #44148 (closed)

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