cmd/compile: 32-bit random data corruption #43570
Description
What version of Go are you using (go version)?
$ go version go version go1.15.6 linux/arm
Does this issue reproduce with the latest release?
Yes
What operating system and processor architecture are you using (go env)?
go env Output
$ go env GO111MODULE="" GOARCH="arm" GOBIN="" GOCACHE="/home/pi-star/.cache/go-build" GOENV="/home/pi-star/.config/go/env" GOEXE="" GOFLAGS="" GOHOSTARCH="arm" GOHOSTOS="linux" GOINSECURE="" GOMODCACHE="/home/pi-star/go/pkg/mod" GONOPROXY="" GONOSUMDB="" GOOS="linux" GOPATH="/home/pi-star/go" GOPRIVATE="" GOPROXY="https://proxy.golang.org,direct" GOROOT="/usr/local/go" GOSUMDB="sum.golang.org" GOTMPDIR="" GOTOOLDIR="/usr/local/go/pkg/tool/linux_arm" GCCGO="gccgo" GOARM="6" AR="ar" CC="gcc" CXX="g++" CGO_ENABLED="1" GOMOD="/home/pi-star/go/src/github.com/golang/32bit-bug/go.mod" CGO_CFLAGS="-g -O2" CGO_CPPFLAGS="" CGO_CXXFLAGS="-g -O2" CGO_FFLAGS="-g -O2" CGO_LDFLAGS="-g -O2" PKG_CONFIG="pkg-config" GOGCCFLAGS="-fPIC -marm -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build227798987=/tmp/go-build -gno-record-gcc-switches"
What did you do?
While running a 32-bit golang executable random data corruption may occur. Here is an example Kubernetes issue which is able to reproduce the problem with 32-bit arm and 386:
kubernetes/kubernetes#97685
The unit test is compiled and attached as a standalone example here:
32bit-bug.tar.gz
Test code, commands, armv6 binaries, and relevant objdump data is available in above tarball.
If the test is compiled without optimizations the test will pass (on arm at least).
(edit: remove link to aarch64 issue)
What did you expect to see?
$ ./passing-arm32-test
PASS
What did you see instead?
$ ./failing-arm32-test
--- FAIL: TestSampler (1.06s)
sample_and_watermark_test.go:48: t0=2021-01-07 11:24:28.746138334 -0700 MST m=+0.016036811
panic: that was a bad year!: 0011-12-20 14:41:53.017034732 -0728 LMT [recovered]
panic: that was a bad year!: 0011-12-20 14:41:53.017034732 -0728 LMT
goroutine 19 [running]:
testing.tRunner.func1.1(0x374e38, 0x122d068)
/usr/local/go/src/testing/testing.go:1072 +0x264
testing.tRunner.func1(0x1082380)
/usr/local/go/src/testing/testing.go:1075 +0x364
panic(0x374e38, 0x122d068)
/usr/local/go/src/runtime/panic.go:969 +0x158
github.com/golang/32bit-bug.(*sampleAndWaterMarkObserverGenerator).quantize(0x10a6150, 0x103edec, 0x103ed78, 0x14a13f43, 0x0, 0x654a80, 0x80c40200, 0x434e01)
/home/pi-star/go/src/github.com/golang/32bit-bug/sample_and_watermark.go:99 +0x164
github.com/golang/32bit-bug.(*sampleAndWaterMarkHistograms).innerSet.func1(0x10b8080, 0x103edec, 0x103edd0, 0x103ee00, 0x103edc4, 0x103ee48)
/home/pi-star/go/src/github.com/golang/32bit-bug/sample_and_watermark.go:175 +0xb4
github.com/golang/32bit-bug.(*sampleAndWaterMarkHistograms).innerSet(0x10b8080, 0x103ee48)
/home/pi-star/go/src/github.com/golang/32bit-bug/sample_and_watermark.go:204 +0x70
github.com/golang/32bit-bug.(*sampleAndWaterMarkHistograms).Set(0x10b8080, 0x0, 0x3ff00000)
/home/pi-star/go/src/github.com/golang/32bit-bug/sample_and_watermark.go:155 +0x54
github.com/golang/32bit-bug.TestSampler(0x1082380)
/home/pi-star/go/src/github.com/golang/32bit-bug/sample_and_watermark_test.go:57 +0x454
testing.tRunner(0x1082380, 0x3ea0c4)
/usr/local/go/src/testing/testing.go:1123 +0xbc
created by testing.(*T).Run
/usr/local/go/src/testing/testing.go:1168 +0x220