runtime: traceback: unexpected SPWRITE function msancall/asancall

[mauri870]

Go version

1.21, 1.22, gotip

Output of go env in your module/workspace:

GO111MODULE=''
GOARCH='amd64'
GOBIN='/home/mauri870/gopath/bin'
GOCACHE='/home/mauri870/.cache/go-build'
GOENV='/home/mauri870/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/home/mauri870/gopath/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/mauri870/gopath'
GOPRIVATE=''
GOPROXY='direct'
GOROOT='/home/mauri870/git/go'
GOSUMDB='off'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/home/mauri870/git/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='devel go1.23-1a8ee033f8 Tue Feb 20 22:55:07 2024 +0000'
GCCGO='/usr/bin/gccgo'
GOAMD64='v1'
AR='ar'
CC='clang-17'
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 -fno-caret-diagnostics -Qunused-arguments -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build273665276=/tmp/go-build -gno-record-gcc-switches'

What did you do?

export CC=clang
go test -run ^TestDebugCallGC$ runtime -v -asan -count 10
go test -run ^TestDebugCallGC$ runtime -v -msan -count 10

What did you see happen?

Crash when running runtime tests with -asan or -msan.

traceback: unexpected SPWRITE function msancall
fatal error: traceback                                                                               

What did you expect to see?

Either src/runtime/debug_test.go tests to pass, or skip these with && linux && !race && !msan && !asan)

[mauri870]

I just confirmed the same issue happens with -race, if the !race tag is removed from src/runtime/debug_test.go.

So the solution is pretty simple, add !msan and !asan to this file.

[gopherbot]

Change https://go.dev/cl/565735 mentions this issue: runtime: fix unexpected SPWRITE func msan/asancall

[prattmic]

@mknyszek do you know if debugcall is intended to work with msan/asan enabled?

[mauri870]

There is a comment in debug_test.go that says:

// We skip all of these tests under race mode because our test thread
// spends all of its time in the race runtime, which isn't a safe
// point.

It says nothing about race being unsupported. Maybe due to the lack of tests (since this one is skipped) it stopped working at some point? Either way, both race, asan and msan make this test panic with the same SPWRITE error.

I'm also curious about the actual race support for debug call.

EDIT: Sometimes the test freeze with debug_test.go:211: executing on Go runtime stack. Looks like there is some flakyness to the error as well.

[mknyszek]

The debug call tests do some really weird things. I'm not really sure anyone who worked on that code thought about msan/asan when writing those tests, so I wouldn't be surprised if there are issues lurking there.