PBO makes the texture plain white

[Silent hallucination]

Hello there.
I wanted to play a video using a quad-stretched texture and for the test I made a simple class that gets a ByteBuffer with the first frame of the video and creates a texture from it. However, when I tried to do the same with PBO (which will allow me to update the texture faster in the future), only a solid white rectangle was displayed.
Here is my texture class now:

public class VidTexture {
    int w, h, textureId, pbo;
    VidTexture(int w, int h, ByteBuffer buf) {
        this.w = w;
        this.h = h;
        buf.flip();

        pbo = glGenBuffers();
        glBindBuffer(GL_PIXEL_UNPACK_BUFFER, pbo);
        glBufferData(GL_PIXEL_UNPACK_BUFFER, w*h*3L, GL_STREAM_DRAW);
        ByteBuffer bb = glMapBuffer(GL_PIXEL_UNPACK_BUFFER, GL_WRITE_ONLY);
        bb.put(buf);
        glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);

        textureId = glGenTextures();

        glUnmapBuffer(GL_PIXEL_UNPACK_BUFFER);

        glBindTexture(GL_TEXTURE_2D, textureId);
        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

        glBindBuffer(GL_PIXEL_UNPACK_BUFFER, pbo);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w,
                h, 0, GL_BGR, GL_UNSIGNED_BYTE, 0);
        glGenerateMipmap(GL_TEXTURE_2D);
        glBindTexture(GL_TEXTURE_2D, -1);
        glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);

        buf.clear();
    }
    //Here is cleanUp and bind functions
}

Can anyone help me, please?