x/sys/cpu: Crash on android arm64 device in release build

[fbzhong]

$ go version
go version go1.13.6 darwin/amd64

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/zzzzz/Library/Caches/go-build"
GOENV="/Users/zzzzz/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/usr/local/go"
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/opt/go/libexec"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/opt/go/libexec/pkg/tool/darwin_amd64"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/Users/zzzzz/Downloads/golang_sys_crash/golib/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 -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/_7/2sw8zmxd5jdd2f1shskh380m0000gn/T/go-build136262396=/tmp/go-build -gno-record-gcc-switches -fno-common"

$ gomobile version
gomobile version +875e90d Wed Jan 15 17:48:49 2020 +0000 (android,ios); androidSDK=/usr/local/Android/sdk/platforms/android-29

Android NDK: 21.0.6113669
Android SDK: 29.0.2
Android Studio: 3.5.3

I have an android app that depends on golang.org/x/sys library. When I upgrade from `golang.org/x/sys' package from golang/sys@6d18c01 to next commit golang/sys@85b82a3 , my android app building in release mode was crashed on my device. I tried Pixel 2 + Android Q, Pixel 4 XL + Android Q and Redmi 6 Pro + Android Pie.

I reproduce this crash and sample code is at https://github.com/fbzhong/SysCrashDemo (including golang lib & Android app). Only one line in the golib:

import (
	"golang.org/x/sys/cpu"
)

func Init(appName, appVersion string) bool {
	return cpu.Initialized
}

Running release APK on device is crashed on my device, debug APK works well. And the last good commit is golang/sys@6d18c01 , the first crash commit is golang/sys@85b82a3 .The following is a crash log:

2020-01-17 17:11:31.963 22689-22689/? A/DEBUG: *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
2020-01-17 17:11:31.963 22689-22689/? A/DEBUG: Build fingerprint: 'google/walleye/walleye:10/QQ1A.191205.008/5974827:user/release-keys'
2020-01-17 17:11:31.963 22689-22689/? A/DEBUG: Revision: 'MP1'
2020-01-17 17:11:31.963 22689-22689/? A/DEBUG: ABI: 'arm64'
2020-01-17 17:11:31.964 22689-22689/? A/DEBUG: Timestamp: 2020-01-17 17:11:31+0800
2020-01-17 17:11:31.964 22689-22689/? A/DEBUG: pid: 22639, tid: 22682, name: sample.syscrash  >>> com.github.fbzhong.sample.syscrash <<<
2020-01-17 17:11:31.964 22689-22689/? A/DEBUG: uid: 10182
2020-01-17 17:11:31.964 22689-22689/? A/DEBUG: signal 4 (SIGILL), code 1 (ILL_ILLOPC), fault addr 0x70f1b7a4a0 (*pc=0xd5380600)
2020-01-17 17:11:31.964 22689-22689/? A/DEBUG:     x0  0000000000000001  x1  00000070f1cbb800  x2  000000400004be60  x3  0000000000000000
2020-01-17 17:11:31.964 22689-22689/? A/DEBUG:     x4  00000070f1c10f20  x5  0000000000000000  x6  0000000000000030  x7  0000000000001000
2020-01-17 17:11:31.964 22689-22689/? A/DEBUG:     x8  0000000000000006  x9  00000000000000f9  x10 000000400008417f  x11 0000000000001000
2020-01-17 17:11:31.964 22689-22689/? A/DEBUG:     x12 0000000000000001  x13 00000070f1bb3907  x14 0000000000000000  x15 00000000000000f9
2020-01-17 17:11:31.964 22689-22689/? A/DEBUG:     x16 0000000000000000  x17 0000000000000000  x18 00000070f127a000  x19 0000000000000006
2020-01-17 17:11:31.964 22689-22689/? A/DEBUG:     x20 000000400004bd10  x21 00000070f1ca0dc0  x22 00000070f1cbbe54  x23 00000070f1cbbe55
2020-01-17 17:11:31.964 22689-22689/? A/DEBUG:     x24 00000070f1c9ffe0  x25 0000000000000018  x26 00000070f1c93cc8  x27 ffffffffffffffb3
2020-01-17 17:11:31.964 22689-22689/? A/DEBUG:     x28 0000004000000180  x29 0000000000000000
2020-01-17 17:11:31.964 22689-22689/? A/DEBUG:     sp  000000400004be40  lr  00000070f1b79d88  pc  00000070f1b7a4a0
2020-01-17 17:11:31.964 22689-22689/? A/DEBUG: backtrace:
2020-01-17 17:11:31.964 22689-22689/? A/DEBUG:       #00 pc 00000000000fa4a0  /data/app/com.github.fbzhong.sample.syscrash-xyOd8b5nMJGIlZFpFS8nAA==/lib/arm64/libgojni.so

Sorry I didn't take more time to find out which line of code caused this crash, hope someone could fix this soon.

[tklauser]

Seems like android doesn't allow reading the ARM64 instruction set attribute and processor feature registers in all cases. Will send a fix.

[gopherbot]

Change https://golang.org/cl/215237 mentions this issue: cpu: don't read ARM64 registers on Android

[fbzhong]

Great, it work well!