Bug 285739 – [GTK] Image surface leak in AcceleratedBackingStoreDMABuf::BufferSHM::didUpdateContents

• Component: WebKitGTK
• Status: RESOLVED FIXED

In AcceleratedBackingStoreDMABuf::BufferSHM::didUpdateContents (https://github.com/WebKit/WebKit/blob/main/Source/WebKit/UIProcess/gtk/AcceleratedBackingStoreDMABuf.cpp#L592) there is a call to `cairo_image_surface_create_for_data` and the return value is directly assigned to a `RefPtr<cairo_surface_t>` without being passed through `adoptRef`. This causes a memory leak.

```
void AcceleratedBackingStoreDMABuf::BufferSHM::didUpdateContents(Buffer*, const WebCore::Region&)
{       
#if USE(CAIRO)
    m_surface = m_bitmap->createCairoSurface();
#elif USE(SKIA)
    m_surface = adoptRef(cairo_image_surface_create_for_data(m_bitmap->mutableSpan().data(), CAIRO_FORMAT_ARGB32, m_size.width(), m_size.height(), m_bitmap->bytesPerRow()));
    m_bitmap->ref();
    static cairo_user_data_key_t s_surfaceDataKey;
    cairo_surface_set_user_data(m_surface.get(), &s_surfaceDataKey, m_bitmap.get(), [](void* userData) {
        static_cast<WebCore::ShareableBitmap*>(userData)->deref();
    }); 
#endif
    cairo_surface_set_device_scale(m_surface.get(), deviceScaleFactor(), deviceScaleFactor());
} 
```

[Michael Catanzaro]

Thanks for reporting this.

[Michael Catanzaro]

Pull request: https://github.com/WebKit/WebKit/pull/38843

[EWS]

Committed 288715@main (697eaa0ed00e): <https://commits.webkit.org/288715@main>

Reviewed commits have been landed. Closing PR #38843 and removing active labels.