Comment 1 for bug 1377853

Both MALLOC_CHECK_ and valgrind agree on the cause of the crash. The nested server is trying to set up and then destroy real DRM resources (which it should not, because it's a nested server):

==29944== Invalid free() / delete / delete[] / realloc()
==29944== at 0x4C2BE10: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==29944== by 0x937F228: ??? (in /usr/lib/x86_64-linux-gnu/libgbm.so.1.0.0)
==29944== by 0xB2F77F0: mir::graphics::mesa::helpers::GBMHelper::~GBMHelper() (display_helpers.cpp:292)
==29944== by 0xB31EC50: mir::graphics::mesa::NativePlatform::~NativePlatform() (native_platform.cpp:51)
==29944== by 0xB322C98: void __gnu_cxx::new_allocator<mir::graphics::mesa::NativePlatform>::destroy<mir::graphics::mesa::NativePlatform>(mir::graphics::mesa::NativePlatform*) (new_allocator.h:124)
==29944== by 0xB322C4A: std::enable_if<std::__and_<std::allocator_traits<std::allocator<mir::graphics::mesa::NativePlatform> >::__destroy_helper<mir::graphics::mesa::NativePlatform>::type>::value, void>::type std::allocator_traits<std::allocator<mir::graphics::mesa::NativePlatform> >::_S_destroy<mir::graphics::mesa::NativePlatform>(std::allocator<mir::graphics::mesa::NativePlatform>&, mir::graphics::mesa::NativePlatform*) (alloc_traits.h:282)
==29944== by 0xB322BF2: void std::allocator_traits<std::allocator<mir::graphics::mesa::NativePlatform> >::destroy<mir::graphics::mesa::NativePlatform>(std::allocator<mir::graphics::mesa::NativePlatform>&, mir::graphics::mesa::NativePlatform*) (alloc_traits.h:411)
==29944== by 0xB322AE4: std::_Sp_counted_ptr_inplace<mir::graphics::mesa::NativePlatform, std::allocator<mir::graphics::mesa::NativePlatform>, (__gnu_cxx::_Lock_policy)2>::_M_dispose() (shared_ptr_base.h:524)
==29944== by 0x4E81CDF: std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release() (shared_ptr_base.h:149)
==29944== by 0x4E81A48: std::__shared_count<(__gnu_cxx::_Lock_policy)2>::~__shared_count() (shared_ptr_base.h:666)
==29944== by 0x4F96393: std::__shared_ptr<mir::graphics::NativePlatform, (__gnu_cxx::_Lock_policy)2>::~__shared_ptr() (shared_ptr_base.h:914)
==29944== by 0x4F963AD: std::shared_ptr<mir::graphics::NativePlatform>::~shared_ptr() (shared_ptr.h:93)
==29944== Address 0xab3cb60 is 0 bytes inside a block of size 5 free'd
==29944== at 0x4C2BE10: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==29944== by 0x714518D: ??? (in /usr/lib/x86_64-linux-gnu/mesa-egl/libEGL.so.1.0.0)
==29944== by 0x713C551: eglTerminate (in /usr/lib/x86_64-linux-gnu/mesa-egl/libEGL.so.1.0.0)
==29944== by 0x50211E4: mir::graphics::nested::detail::EGLDisplayHandle::~EGLDisplayHandle() (nested_display.cpp:119)
==29944== by 0x5021513: mir::graphics::nested::NestedDisplay::~NestedDisplay() (nested_display.cpp:141)
==29944== by 0x502DBA4: void __gnu_cxx::new_allocator<mir::graphics::nested::NestedDisplay>::destroy<mir::graphics::nested::NestedDisplay>(mir::graphics::nested::NestedDisplay*) (new_allocator.h:124)
==29944== by 0x502DB56: std::enable_if<std::__and_<std::allocator_traits<std::allocator<mir::graphics::nested::NestedDisplay> >::__destroy_helper<mir::graphics::nested::NestedDisplay>::type>::value, void>::type std::allocator_traits<std::allocator<mir::graphics::nested::NestedDisplay> >::_S_destroy<mir::graphics::nested::NestedDisplay>(std::allocator<mir::graphics::nested::NestedDisplay>&, mir::graphics::nested::NestedDisplay*) (alloc_traits.h:282)
==29944== by 0x502DAFE: void std::allocator_traits<std::allocator<mir::graphics::nested::NestedDisplay> >::destroy<mir::graphics::nested::NestedDisplay>(std::allocator<mir::graphics::nested::NestedDisplay>&, mir::graphics::nested::NestedDisplay*) (alloc_traits.h:411)
==29944== by 0x502D9F0: std::_Sp_counted_ptr_inplace<mir::graphics::nested::NestedDisplay, std::allocator<mir::graphics::nested::NestedDisplay>, (__gnu_cxx::_Lock_policy)2>::_M_dispose() (shared_ptr_base.h:524)
==29944== by 0x4E81CDF: std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release() (shared_ptr_base.h:149)
==29944== by 0x4E81A48: std::__shared_count<(__gnu_cxx::_Lock_policy)2>::~__shared_count() (shared_ptr_base.h:666)
==29944== by 0x4E85D79: std::__shared_ptr<mir::graphics::Display, (__gnu_cxx::_Lock_policy)2>::~__shared_ptr() (shared_ptr_base.h:914