Android 5.1崩溃--glDrawArrays GL_POINTS--致命信号7(SIGBUS)，代码2。

Question

几个月前，我将我的Nexus 4更新到Android 5.1（现在是5.1.1 - 都是来自Google的原始工厂映像），其中一个游戏在使用glDrawArrays和GL_POINTS绘制粒子时开始崩溃。我已经简化了代码，并用Java重新实现，复制了这个崩溃。

崩溃总是致命信号7（SIGBUS），代码2似乎是OpenGL驱动程序代码。

在这个测试中，对于我来说，在for循环中有118个drawPoint()调用，一切都运行正常，但如果我尝试119个drawPoint()调用，则会崩溃（下一帧）。任何数量的drawPoint()调用，超过119个，也会导致崩溃。

这段Java代码在Nexus 4虚拟设备上运行良好。原始的C代码在PC、iOS和其他Android设备上都没有任何问题。

这似乎可能是Nexus 4驱动程序的问题。有什么想法吗？

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@[e-mail]

MainActivity.java 的代码：

// 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

- Joe

---

也许内存存在一些有缺陷的比特。你认为是硬件问题吗？ - user4628051

听起来很可能是驱动程序的错误。如果堆栈跟踪有任何迹象，问题不在于顶点数据本身，而是在尝试设置某种事件时崩溃了。特别是如果您可以在Java中重现它，在那里您不能轻易地践踏内存，我不认为这可能是您的错。 - Reto Koradi

我认为这不是一个纯硬件问题，因为在更新到5.1之前，相同的代码在相同的硬件（我的Nexus 4）上运行正常。这也是完全可重复的。而且，118个循环可以工作，但119个就不行了。 - Joe

我已经在Android问题跟踪器网站上发布了这个问题。https://code.google.com/p/android/issues/detail?id=177219 - Joe

Answer 1

你的VS中有attribute vec4 vPos;，它是4个浮点数，但是你每个顶点只上传了3个浮点数...请像这样更改你的顶点着色器：

attribute vec4 vPos; --> attribute vec3 vPos;

另外

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

- agnu17

---

顶点属性中的组件数可以比着色器中的属性变量少，这是完全有效的，在这种情况下，“w”组件会自动设置为1。该行为已经很好地定义了。 - Reto Koradi

这个更改后仍然导致代码崩溃，结果相同。 - Joe