Android App crashes in renderscript code

Question

This is my renderscript code that implements BoxBlur:

#pragma version(1)
#pragma rs java_package_name(com.karthik.imgproc)

rs_allocation pixelAlloc;
rs_allocation indices;
uint width;
uint height;
int radius;

void root(const uint *v_in, uchar4 *v_out) {
    uint row = *v_in >> 16 & 0xffff;
    uint col = *v_in & 0xffff;
    uint sumR = 0;
    uint sumG = 0;
    uint sumB = 0;
    int yr = 0;
    int xr = 0;
    for(yr = -radius; yr <= radius; yr++){
        for(xr = -radius; xr <= radius; xr++){
            int a = row + xr;
            int b = col + yr;
            if(a < 0 || b < 0)
                continue;
            uchar4 p = rsGetElementAt_uchar4(pixelAlloc, a, b);
            sumR = sumR + p.r;
            sumG = sumG + p.g;
            sumB = sumB + p.b;
        }
    }
    uint divisor = ((radius * 2) + 1) * ((radius * 2) + 1);
    float R = sumR / divisor;
    float G = sumG / divisor;
    float B = sumB / divisor;

    float A = rsGetElementAt_uchar4(pixelAlloc, row, col).a;
    if(R > 255)
        R = 255;
    if(R < 0)
        R = 0;
    if(G > 255)
        G = 255;
    if(G < 0)
        G = 0;
    if(B > 255)
        B = 255;
    if(B < 0)
        B = 0;
    R = R/255;
    G = G/255;
    B = B/255;
    A = A/255;
    *v_out = rsPackColorTo8888(R,G,B,A);
}

This is the java code that initiates renderscript code execution

private void convolve(final Bitmap srcBmp, int radius){
    int width = srcBmp.getWidth();
    int height = srcBmp.getHeight();
    Allocation inPixels = Allocation.createFromBitmap(mRs, srcBmp, Allocation.MipmapControl.MIPMAP_NONE, Allocation.USAGE_SHARED);
    inPixels.copyFrom(srcBmp);
    ScriptC_convolve script = new ScriptC_convolve(mRs);
    script.set_width(width);
    script.set_height(height);
    script.set_radius(radius);
    script.set_pixelAlloc(inPixels);

    Allocation in = Allocation.createTyped(mRs, Type.createXY(mRs, Element.U32(mRs), srcBmp.getWidth(), srcBmp.getHeight()), Allocation.USAGE_SCRIPT);
    int pixelIndices[] = new int[srcBmp.getWidth() * srcBmp.getHeight()];
    int i = 0;
    for(int col=0; col<width; col++){
        for(int row=0; row<height; row++, i++){
            pixelIndices[i] = (row << 16) | col ;
        }
    }
    in.copy2DRangeFrom(0, 0, srcBmp.getWidth(), srcBmp.getHeight(), pixelIndices);
    final Bitmap dstBitmap = Bitmap.createBitmap(srcBmp.getWidth(), srcBmp.getHeight(), srcBmp.getConfig());
    Allocation out = Allocation.createTyped(mRs, inPixels.getType(), Allocation.USAGE_SHARED);
    script.forEach_root(in, out);
    out.copyTo(dstBitmap);
   ((ImageView)findViewById(R.id.dstImgView)).setImageDrawable(new BitmapDrawable(getResources(), dstBitmap));
    script.destroy();
}

The problem is app crashes everytime with following logs:

F/libc    (28885): Fatal signal 7 (SIGBUS), code 2, fault addr 0xa3369000 in tid 28922 (imageprocessing)
F/libc    (28885): Fatal signal 7 (SIGBUS), code 2, fault addr 0xa3369820 in tid 28920 (imageprocessing)
F/libc    (28885): Fatal signal 7 (SIGBUS), code 2, fault addr 0xa336da20 in tid 28921 (imageprocessing)
I/DEBUG   (15097): *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
I/DEBUG   (15097): Build fingerprint: 'motorola/falcon_asia_ds/falcon_umtsds:5.0.2/LXB22.46-28/30:user/release-keys'
I/DEBUG   (15097): Revision: 'p3c0'
I/DEBUG   (15097): ABI: 'arm'
I/DEBUG   (15097): pid: 28885, tid: 28922, name: imageprocessing  >>> imageeffect.kpbird.com.imageprocessing <<<
I/DEBUG   (15097): signal 7 (SIGBUS), code 2 (BUS_ADRERR), fault addr 0xa3369000
I/DEBUG   (15097):     r0 00000001  r1 a320f020  r2 000001f7  r3 a2c27000
I/DEBUG   (15097):     r4 00159fe0  r5 00000b00  r6 00000000  r7 000000b7
I/DEBUG   (15097):     r8 00000000  r9 00000000  sl 00000001  fp 000000b8
I/DEBUG   (15097):     ip 00000000  sp a682dc94  lr ffffffff  pc a2c230fc  cpsr 200f0010
I/DEBUG   (15097):
I/DEBUG   (15097): backtrace:
I/DEBUG   (15097):     #00 pc 000000fc  /dev/kgsl-3d0
I/DEBUG   (15097):     #01 pc fffffffd  <unknown>
I/DEBUG   (15097):
I/DEBUG   (15097): Tombstone written to: /data/tombstones/tombstone_07
E/        (15097): tid 28920 does not exist in pid 28885. ignoring debug request
E/        (15097): tid 28921 does not exist in pid 28885. ignoring debug request
I/BootReceiver(  988): Copying /data/tombstones/tombstone_07 to DropBox (SYSTEM_TOMBSTONE)
W/ActivityManager(  988):   Force finishing activity imageeffect.kpbird.com.imageprocessing/com.karthik.imgproc.MainActivity
I/WindowState(  988): WIN DEATH: Window{18f03389 u0 imageeffect.kpbird.com.imageprocessing/com.karthik.imgproc.MainActivity}

I don't understand why the app crashes. But for very small images say 25x25 resolution its working fine. Interesting observation here is when I comment out *v_out = rsPackColorTo8888(R,G,B,A) in renderscript code, app is not crashing ofcourse nothing will be shown. My question is why it is crashing at rsPackColorTo8888(R,G,B,A)? Is there any problem in the way I implemented. Why it is working for very small images? For most of the images app crashes.

Miloslaw Smyk · Answer 1 · 2015-07-29T22:15:37.977

This code has many problems. Suggestions:

check upper bounds too (if(a < 0 || b < 0) only checks lower bounds),
don't divide int by int and expect float precision result (float R = sumR / divisor;)
use clamp() rather than checking RGB values against 0 and 255,
use vector types instead of processing R, G, and B components individually.

The first issue can lead to crashes. The second - introduces visual artifacts. The rest slows things down.

score 0 · Answer 2 · answered Jul 30 '15 at 10:43

@Laubzega

Thanks for the clues! Finally I got resolution. In addition to your first point i.e., checking upper bounds, I should also change code in java to send (x,y) location of pixels properly as follows:

for(int y=0; y < height; y++){
    for(int x=0; x < width; x++, i++){
        pixelIndices[i] = (x << 16) | y ;
    }
}

Now the app works fine without any crash!!

Android App crashes in renderscript code

2 Answers2