QTextureGlyphCache seg faults during the destruction of the font engine in app exit

Reproducible on Unix with graphicssystem opengl enabled by running either unit tests /tests/auto/declarative/qdeclarativetextedit or /tests/auto/declarative/qdeclarativetextinput.

QGLTextureGlyphCache::~QGLTextureGlyphCache()
{
    if (ctx) { // not null
        QGLShareContextScope scope(ctx); // ctx becomes null

        if (!ctx->d_ptr->workaround_brokenFBOReadBack) // seg fault, new line done by commit 9a69656b on 15th of May
            glDeleteFramebuffers(1, &m_fbo);

        if (m_width || m_height)
            glDeleteTextures(1, &m_texture);
    }
}

Stack trace:
0 QScopedPointer<QGLContextPrivate, QScopedPointerDeleter<QGLContextPrivate> >::operator-> qscopedpointer.h 112 0xb71e0895
1 ~QGLTextureGlyphCache qtextureglyphcache_gl.cpp 78 0xb725d21c
2 ~QFontEngine qfontengine.cpp 190 0xb694e1ab
3 ~QFontEngineFT qfontengine_ft.cpp 639 0xb6a4ef82
4 ~QFontEngineX11FT qfontengine_x11.cpp 1123 0xb6a43f8a
5 ~QFontEngineMulti qfontengine.cpp 1282 0xb694e66c
6 ~QFontEngineMultiFT qfontengine_x11.cpp 902 0xb6a44cc8
7 QFontCache::clear qfont.cpp 2695 0xb693dc93
8 ~QFontCache qfont.cpp 2635 0xb693ed03
9 QThreadStorage<QFontCache*>::deleteData qthreadstorage.h 133 0xb6944612
10 QThreadStorageData::set qthreadstorage.cpp 148 0xb60cef33
11 qThreadStorage_setLocalData<QFontCache> qthreadstorage.h 92 0xb69465a8
12 QThreadStorage<QFontCache*>::setLocalData qthreadstorage.h 148 0xb69465c6
13 QFontCache::cleanup qfont.cpp 2623 0xb693fd64
14 QFont::cleanup qfont_x11.cpp 182 0xb6a4220d
15 qt_cleanup qapplication_x11.cpp 2596 0xb6730b60
16 ~QApplication qapplication.cpp 1110 0xb6695535
17 main tst_qdeclarativetextedit.cpp 928 0x08058694