Android 5.1 crash -- glDrawArrays GL_POINTS -- Fatal signal 7 (SIGBUS), code 2

Question

A couple months ago, after I update my Nexus 4 to Android 5.1 (now 5.1.1 -- both stock factory images from Google), one of my games started crashing while drawing particles using glDrawArrays with GL_POINTS. I've simplified, reimplemented the code in Java, and replicated the crash.

The crash is always a Fatal signal 7 (SIGBUS), code 2 in what seems to be OpenGL driver code.

In this test, for me, with 118 drawPoint() calls in the for-loop, everything seems to run OK, but crashes (the next frame) if I try 119 drawPoint() calls. Any number of calls to drawPoint(), more than 119, also crashes.

This Java code runs OK on the Nexus 4 virtual device. The original C code runs on the PC, iOS, and other Android devices without any problems.

This seems like it could be a Nexus 4 driver problem. Any ideas?

Logcat:

--------- beginning of crash
A/libc﹕ Fatal signal 7 (SIGBUS), code 2, fault addr 0xa2876000 in tid 17998 (GLThread 14477)
I/DEBUG﹕ *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
I/DEBUG﹕ Build fingerprint: 'google/occam/mako:5.1.1/LMY47V/1836172:user/release-keys'
I/DEBUG﹕ Revision: '11'
I/DEBUG﹕ ABI: 'arm'
I/DEBUG﹕ pid: 17822, tid: 17998, name: GLThread 14477  >>> com.joeco.pointsprites <<<
I/DEBUG﹕ signal 7 (SIGBUS), code 2 (BUS_ADRERR), fault addr 0xa2876000
I/DEBUG﹕ r0 c0004600  r1 a2876000  r2 04000000  r3 a2876000
I/DEBUG﹕ r4 b7755818  r5 00000000  r6 b776d550  r7 00000018
I/DEBUG﹕ r8 b776d550  r9 04000000  sl 00008000  fp 00000000
I/DEBUG﹕ ip fc000000  sp a4601850  lr abad3c91  pc abac38e6  cpsr 60030030
I/DEBUG﹕ backtrace:
I/DEBUG﹕ #00 pc 000ab8e6  /system/vendor/lib/egl/libGLESv2_adreno.so (oxili_write_event_write+41)
I/DEBUG﹕ #01 pc 000bbc8d  /system/vendor/lib/egl/libGLESv2_adreno.so (oxili_wa_predraw+234)
I/DEBUG﹕ #02 pc 000bbef1  /system/vendor/lib/egl/libGLESv2_adreno.so (oxili_wa_point_sprite_dummy_draw+204)
I/DEBUG﹕ #03 pc 000ba47b  /system/vendor/lib/egl/libGLESv2_adreno.so (oxili_primitive_drawarrays+318)
I/DEBUG﹕ #04 pc 000825cf  /system/vendor/lib/egl/libGLESv2_adreno.so (rb_primitive_drawarrays+298)
I/DEBUG﹕ #05 pc 0005a4f7  /system/vendor/lib/egl/libGLESv2_adreno.so (core_glDrawArraysInstancedXXX+294)
I/DEBUG﹕ #06 pc 0005a877  /system/vendor/lib/egl/libGLESv2_adreno.so (core_glDrawArrays+6)
I/DEBUG﹕ #07 pc 00049acb  /system/vendor/lib/egl/libGLESv2_adreno.so (glDrawArrays+24)
I/DEBUG﹕ #08 pc 00a5befb  /data/dalvik-cache/arm/system@framework@boot.oat

The code for MainActivity.java:

// MainActivity.java -- pointsprite crash -- Joe Linhoff 6/15/2015
package com.joeco.pointsprites;

import android.app.Activity;
import android.content.Context;
import android.opengl.GLES20;
import android.opengl.GLSurfaceView;
import android.opengl.Matrix;
import android.os.Bundle;
import android.os.SystemClock;

import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.ByteBuffer;

import javax.microedition.khronos.opengles.GL10;

// starting point: http://developer.android.com/training/graphics/opengl/index.html

public class MainActivity extends Activity {

    public GLSurfaceView mGLView;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mGLView = new MyGLSurfaceView(this);
        setContentView(mGLView);
    } // onCreate()

    class MyGLSurfaceView extends GLSurfaceView {
        private final MyGLRenderer mRenderer;
        public MyGLSurfaceView(Context context) {
            super(context);
            setEGLContextClientVersion(2); // create OpenGL ES 2.0 context
            mRenderer = new MyGLRenderer();
            setRenderer(mRenderer);
            setRenderMode(GLSurfaceView.RENDERMODE_CONTINUOUSLY);
        } // MyGLSurfaceView()
    } // class MyGLSurvaceView

    public class PointGeo {

        FloatBuffer vertexBuffer;
        static final int floatsPerVertex = 3;
        float pointCoords[] = { 0.1f, 0.0f, 0.0f }; // xyz
        final int vertexCount = pointCoords.length / floatsPerVertex;
        final int vertexStride = floatsPerVertex * 4; // 4 bytes per float

        public PointGeo() {
            ByteBuffer bb = ByteBuffer.allocateDirect(pointCoords.length * 4); // each is 4 bytes
            bb.order(ByteOrder.nativeOrder()); // device's native byte order
            vertexBuffer = bb.asFloatBuffer(); // create floating point buffer
            vertexBuffer.put(pointCoords); // copy coordinates into buffer
            vertexBuffer.position(0); // set to first item
        } // PointGeo()

    } // class PointGeo

    public class MyGLRenderer implements GLSurfaceView.Renderer {

        private boolean mSetup = false;
        private PointGeo mPoint;
        private int mTriangleShaderProgram;
        private int mTriangleShaderLoc_uMVPMat;
        private int mTriangleShaderLoc_vPos;
        private float[] mViewMat = new float[16];
        private float[] mModelMat = new float[16];
        private float[] mProjMat = new float[16];
        private float[] mMVPMat = new float[16];

        public void onDrawFrame(GL10 unused) {

            if(!mSetup)
                lazySetup();

            GLES20.glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
            GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);

            // build model matrix -- rotate
            int time = (int)SystemClock.uptimeMillis() & 8191;
            float angleInDegrees = (360.0f / 8191.0f) * time;
            Matrix.setIdentityM(mModelMat, 0);
            Matrix.rotateM(mModelMat, 0, angleInDegrees, 0.0f, 0.0f, 1.0f);

            // draw -- 118:ok 119:crash on next frame
            for(int i=0;i<119;i++)
                drawPoint();

        } // onDrawFrame()

        void drawPoint()
        {
            // setup
            GLES20.glUseProgram(mTriangleShaderProgram);
            GLES20.glEnableVertexAttribArray(mTriangleShaderLoc_vPos);
            GLES20.glVertexAttribPointer(mTriangleShaderLoc_vPos, mPoint.floatsPerVertex,
                    GLES20.GL_FLOAT, false, mPoint.vertexStride, mPoint.vertexBuffer);

            // build mvp matrix
            Matrix.multiplyMM(mMVPMat,0,mViewMat,0,mModelMat,0);
            Matrix.multiplyMM(mMVPMat, 0, mProjMat, 0, mMVPMat, 0);
            GLES20.glUniformMatrix4fv(mTriangleShaderLoc_uMVPMat, 1, false, mMVPMat, 0);

            // draw
            GLES20.glDrawArrays(GLES20.GL_POINTS, 0, mPoint.vertexCount);

            // finish
            GLES20.glDisableVertexAttribArray(mTriangleShaderLoc_vPos);
            GLES20.glUseProgram(0);
        } // drawPoint()

        @Override
        public void onSurfaceCreated(GL10 gl10, javax.microedition.khronos.egl.EGLConfig eglConfig) {
        } // onSurfaceCreated()

        public void onSurfaceChanged(GL10 unused, int width, int height) {
            GLES20.glViewport(0, 0, width, height);

            // create projection matrix
            final float ratio = (float) width / height;
            final float left = -ratio;
            final float right = ratio;
            final float bottom = -1.0f;
            final float top = 1.0f;
            final float near = 1.0f;
            final float far = 10.0f;
            Matrix.frustumM(mProjMat, 0, left, right, bottom, top, near, far);
        } // onSurfaceChanged()

        public int loadShader(int type, String shaderCode) {
            int shader = GLES20.glCreateShader(type); // create shader
            GLES20.glShaderSource(shader, shaderCode); // add source
            GLES20.glCompileShader(shader); // compile
            return shader;
        } // loadShader()

        private final String vertexShaderCode =
                "attribute vec4 vPos;" +
                "uniform mat4 uMVPMat;" +
                "void main() {" +
                "  gl_Position = vPos*uMVPMat;" +
                "  gl_PointSize = 40.0f; " +
                "}";

        private final String fragmentShaderCode =
                "void main() {" +
                "  gl_FragColor = vec4(0.5f,0.7f,0.5f,1.f);" +
                "}";

        void lazySetup()
        {
            mSetup=true;
            mPoint = new PointGeo();
            int vshader = loadShader(GLES20.GL_VERTEX_SHADER,vertexShaderCode);
            int fshader = loadShader(GLES20.GL_FRAGMENT_SHADER,fragmentShaderCode);
            mTriangleShaderProgram = GLES20.glCreateProgram();
            GLES20.glAttachShader(mTriangleShaderProgram, vshader);
            GLES20.glAttachShader(mTriangleShaderProgram, fshader);
            GLES20.glLinkProgram(mTriangleShaderProgram);
            int err = GLES20.glGetError();

            mTriangleShaderLoc_uMVPMat = GLES20.glGetUniformLocation(mTriangleShaderProgram, "uMVPMat");
            mTriangleShaderLoc_vPos = GLES20.glGetAttribLocation(mTriangleShaderProgram, "vPos");

            setViewMat();
            Matrix.setIdentityM(mModelMat,0);

        } // lazySetup()

        void setViewMat()
        {
            final float eyeX = 0.0f;
            final float eyeY = 0.0f;
            final float eyeZ = 5.0f;

            final float lookX = 0.0f;
            final float lookY = 0.0f;
            final float lookZ = -1.0f;

            final float upX = 0.0f;
            final float upY = 1.0f;
            final float upZ = 0.0f;
            Matrix.setLookAtM(mViewMat, 0, eyeX, eyeY, eyeZ,
                    lookX, lookY, lookZ, upX, upY, upZ);
        } // setViewMat()

    } // class MyGLRenderer

} // class MainActivity

Maybe the memory has some defect bits. Do you think the hardware is the problem? — , Jun 15 '15 at 08:35
Sounds like it's likely a driver bug. If the stack trace is any indication, the problem is not with the vertex data itself, but it crashes while trying to set up some kind of event. Particularly if you can reproduce it in Java, where you can't easily stomp on memory, I don't see how this could be your fault. — Reto Koradi, Jun 15 '15 at 15:27
I don't think it's a pure hardware problem since the same code worked on the same hardware (my Nexus 4) before the update to 5.1. It is also entirely repeatable. And, 118 loops works, but not 119. — Joe, Jun 15 '15 at 22:44
I've posted this as a question on Android's issue tracker site.https://code.google.com/p/android/issues/detail?id=177219 — Joe, Jun 25 '15 at 10:23

agnu17 · Answer 1 · 2015-06-15T09:05:01.670

0

you have attribute vec4 vPos; in your VS, which is 4 floats, but you upload only 3 floats per vertex... change your vertex shader like this:

attribute vec4 vPos; --> attribute vec3 vPos;

Also

gl_Position = vPos * uMVPMat; --> gl_Position = vec4(vPos, 1.0) * uMVPMat;

edited Jun 15 '15 at 09:05

answered Jun 15 '15 at 08:58

agnu17

398
2
9

1

It's perfectly valid to have fewer components in the vertex attributes than in the attribute variable in the shader. The behavior is well defined. In this case, the `w` component is automatically set to 1. – Reto Koradi Jun 15 '15 at 15:20
Same result with this change -- the code still crashes. – Joe Jun 15 '15 at 22:45

Android 5.1 crash -- glDrawArrays GL_POINTS -- Fatal signal 7 (SIGBUS), code 2

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