Try to play any video on youtube.com and you'll immediately hit this assertion in CoordinatedGraphicsLayer's destructor: ASSERT(!m_nicosia.imageBacking); I'll attach a full backtrace. Here's a truncated one: #0 0x00007fdef9e64f43 in WTFCrash () at /home/mcatanzaro/Projects/WebKit/Source/WTF/wtf/Assertions.cpp:267 #1 0x00007fdefbef8193 in WebCore::CoordinatedGraphicsLayer::~CoordinatedGraphicsLayer ( this=0x7fde7cdc4780, __in_chrg=<optimized out>) at /home/mcatanzaro/Projects/WebKit/Source/WebCore/platform/graphics/texmap/coordinated/CoordinatedGraphicsLayer.cpp:141 #2 0x00007fdefbef86cb in WebCore::CoordinatedGraphicsLayer::~CoordinatedGraphicsLayer ( this=0x7fde7cdc4780, __in_chrg=<optimized out>) at /home/mcatanzaro/Projects/WebKit/Source/WebCore/platform/graphics/texmap/coordinated/CoordinatedGraphicsLayer.cpp:135 #3 0x00007fdefd45c23b in std::default_delete<WebCore::GraphicsLayer>::operator() ( __ptr=<optimized out>, this=0x7fde80d3dbd0) at /home/mcatanzaro/Projects/WebKit/Source/WebCore/rendering/RenderLayerBacking.cpp:468 #4 std::unique_ptr<WebCore::GraphicsLayer, std::default_delete<WebCore::GraphicsLayer> >::reset ( __p=<optimized out>, this=0x7fde80d3dbd0) at /usr/include/c++/8/bits/unique_ptr.h:382 #5 std::unique_ptr<WebCore::GraphicsLayer, std::default_delete<WebCore::GraphicsLayer> >::operator=(decltype(nullptr)) (this=0x7fde80d3dbd0) at /usr/include/c++/8/bits/unique_ptr.h:318 #6 WebCore::RenderLayerBacking::destroyGraphicsLayers (this=this@entry=0x7fde80d3dbb0) at /home/mcatanzaro/Projects/WebKit/Source/WebCore/rendering/RenderLayerBacking.cpp:468 #7 0x00007fdefd482834 in WebCore::RenderLayerBacking::~RenderLayerBacking (this=0x7fde80d3dbb0, __in_chrg=<optimized out>) at /home/mcatanzaro/Projects/WebKit/Source/WebCore/rendering/RenderLayerBacking.cpp:249 #8 0x00007fdefd482903 in WebCore::RenderLayerBacking::~RenderLayerBacking (this=0x7fde80d3dbb0, __in_chrg=<optimized out>) at /home/mcatanzaro/Projects/WebKit/Source/WebCore/rendering/RenderLayerBacking.cpp:238 #9 0x00007fdefd4829c9 in std::default_delete<WebCore::RenderLayerBacking>::operator() ( __ptr=<optimized out>, this=0x7fde80d57960) at /home/mcatanzaro/Projects/WebKit/Source/WebCore/rendering/RenderLayer.cpp:5977 #10 std::unique_ptr<WebCore::RenderLayerBacking, std::default_delete<WebCore::RenderLayerBacking> >::reset (__p=<optimized out>, this=0x7fde80d57960) at /usr/include/c++/8/bits/unique_ptr.h:382
Created attachment 348680 [details] Full backtrace
BTW, these destructors are quite tricky (bug #180232)
Created attachment 348906 [details] Patch
Comment on attachment 348906 [details] Patch Clearing flags on attachment: 348906 Committed r235671: <https://trac.webkit.org/changeset/235671>
All reviewed patches have been landed. Closing bug.