When running coverage in a concurrent program, use the -mode=atomic flag to avoid data races in the counters. This unavoidably has a significant performance hit, but it should resolve this race.
-rob On Sun, Oct 2, 2022 at 5:10 AM Shulhan <m.shul...@gmail.com> wrote: > Hi gophers, > > The latest Go tip always fail with data race when running with -race > and -coverprofile options. > > Here is an example of data race output, > > ---- > $ CGO_ENABLED=1 go test -failfast -race -count=1 -coverprofile=cover.out > ./... > ... > ================== > WARNING: DATA RACE > Read at 0x000001e5f04c by main goroutine: > > internal/coverage/encodecounter.(*CoverageDataWriter).writeCounters.func2() > /home/ms/opt/go/src/internal/coverage/encodecounter/encode.go:261 > +0x11c > runtime/coverage.(*emitState).VisitFuncs() > /home/ms/opt/go/src/runtime/coverage/emit.go:539 +0x6bc > internal/coverage/encodecounter.(*CoverageDataWriter).writeCounters() > /home/ms/opt/go/src/internal/coverage/encodecounter/encode.go:268 > +0x16f > internal/coverage/encodecounter.(*CoverageDataWriter).AppendSegment() > /home/ms/opt/go/src/internal/coverage/encodecounter/encode.go:175 > +0x8ea > internal/coverage/encodecounter.(*CoverageDataWriter).Write() > /home/ms/opt/go/src/internal/coverage/encodecounter/encode.go:71 > +0x97 > runtime/coverage.(*emitState).emitCounterDataFile() > /home/ms/opt/go/src/runtime/coverage/emit.go:573 +0x91 > runtime/coverage.emitCounterDataToDirectory() > /home/ms/opt/go/src/runtime/coverage/emit.go:322 +0x310 > runtime/coverage.processCoverTestDir() > /home/ms/opt/go/src/runtime/coverage/testsupport.go:39 +0x1c4 > main.coverTearDown() > _testmain.go:179 +0x159 > testing.coverReport2() > /home/ms/opt/go/src/testing/newcover.go:37 +0xcb > testing.coverReport() > /home/ms/opt/go/src/testing/cover.go:83 +0xc74 > testing.(*M).writeProfiles() > /home/ms/opt/go/src/testing/testing.go:2053 +0xc6f > testing.(*M).after.func1() > /home/ms/opt/go/src/testing/testing.go:1987 +0x30 > sync.(*Once).doSlow() > /home/ms/opt/go/src/sync/once.go:74 +0x101 > sync.(*Once).Do() > /home/ms/opt/go/src/sync/once.go:65 +0x46 > testing.(*M).after() > /home/ms/opt/go/src/testing/testing.go:1986 +0x55 > testing.(*M).Run.func4() > /home/ms/opt/go/src/testing/testing.go:1761 +0x39 > runtime.deferreturn() > /home/ms/opt/go/src/runtime/panic.go:476 +0x32 > testing.(*M).Run() > /home/ms/opt/go/src/testing/testing.go:1771 +0xbb3 > github.com/shuLhan/share/lib/dns.TestMain() > /home/ms/go/src/github.com/shuLhan/share/lib/dns/dns_test.go:63 > +0x5db > main.main() > _testmain.go:192 +0x33d > > Previous write at 0x000001e5f04c by goroutine 9: > sync/atomic.AddInt32() > /home/ms/opt/go/src/runtime/race_amd64.s:281 +0xb > sync/atomic.AddUint32() > <autogenerated>:1 +0x1a > github.com/shuLhan/share/lib/dns.(*Server).processRequest() > /home/ms/go/src/github.com/shuLhan/share/lib/dns/server.go:593 > +0xc67 > github.com/shuLhan/share/lib/dns.(*Server).ListenAndServe.func1() > /home/ms/go/src/github.com/shuLhan/share/lib/dns/server.go:187 +0x39 > > Goroutine 9 (running) created at: > github.com/shuLhan/share/lib/dns.(*Server).ListenAndServe() > /home/ms/go/src/github.com/shuLhan/share/lib/dns/server.go:187 +0xe6 > github.com/shuLhan/share/lib/dns.TestMain.func1() > /home/ms/go/src/github.com/shuLhan/share/lib/dns/dns_test.go:54 > +0x44 > ================== > ... > ---- > > There are many lines like that with the same pattern. > > In the above snippet, the lib/dns/dns_test.go:63 point this code [1], > > os.Exit(m.Run()) > > So it does not make sense if the data race is in my code. > > A quick bisect point to this commit [2]. > > If someone can confirm this, I will submit an issue to GitHub. > > [1] > https://github.com/shuLhan/share/blob/61720a183756bdf5a8af45e7d75116ce7ef188e0/lib/dns/dns_test.go#L63 > [2] > https://go.googlesource.com/go/+/53773a5d0892be4489b4d5e91bbc8ae61000ada7%5E%21/ > > -- > { "git":"git.sr.ht/~shulhan", "site":"kilabit.info" } > > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golang-nuts+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/20221002011006.4ffaaaec%40inspiro.localdomain > . > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CAOXNBZTR_Y2-UMrqCYspmqRBMPzOgAmSCc6fCiqZNpppLGbLqQ%40mail.gmail.com.
