Bit-level false positives in riched20.dll (rich edit)

_From [rnk@google.com](https://code.google.com/u/rnk@google.com/) on February 21, 2012 18:00:31_

Docs on the functionality: http://msdn.microsoft.com/en-us/library/windows/desktop/bb787605(v=vs.85).aspx Most Chrome code that exercises text boxes generates reports in this dll. The first failing test I see is GenericInfoViewTest.GenericInfoView.

I get reports like:

~~Dr.M~~ Error `#5`: UNINITIALIZED READ: reading 0x001ede98-0x001ede99 1 byte(s)
~~Dr.M~~ # 0 RICHED20.dll!? +0x0 (0x72df27cc )
~~Dr.M~~ # 1 RICHED20.dll!? +0x0 (0x72df2471 )
~~Dr.M~~ # 2 RICHED20.dll!? +0x0 (0x72df220c )
~~Dr.M~~ # 3 USER32.dll!gapfnScSendMessage +0x331 (0x753862fa )
~~Dr.M~~ # 4 USER32.dll!GetThreadDesktop +0xd6 (0x75386d3a )
~~Dr.M~~ # 5 USER32.dll!GetClientRect +0xc4 (0x75390d27 )
~~Dr.M~~ # 6 USER32.dll!CallWindowProcW +0x1a (0x75390d4d )
~~Dr.M~~ # 7 ATL::CWindowImplBaseTWTL::CRichEditCtrlT >::DefWindowProcW [c:\program files (x86)\microsoft visual studio 9.0\vc\atlmfc\include\atlwin.h:3030]
~~Dr.M~~ # 8 ATL::CWindowImplBaseTWTL::CRichEditCtrlT >::WindowProc [c:\program files (x86)\microsoft visual studio 9.0\vc\atlmfc\include\atlwin.h:3089]
~~Dr.M~~ # 9 USER32.dll!gapfnScSendMessage
~~Dr.M~~ `#10` USER32.dll!GetThreadDesktop
~~Dr.M~~ `#11` USER32.dll!GetWindow
~~Dr.M~~ `#12` USER32.dll!SendMessageW
~~Dr.M~~ `#13` WTL::CRichEditCtrlTATL::CWindow::GetOleInterface [third_party\wtl\include\atlctrls.h:8016]
~~Dr.M~~ `#14` views::NativeTextfieldWin::NativeTextfieldWin [ui\views\controls\textfield\native_textfield_win.cc:122]
~~Dr.M~~ `#15` views::NativeTextfieldWrapper::CreateWrapper [ui\views\controls\textfield\native_textfield_win.cc:1163]
~~Dr.M~~ `#16` views::Textfield::ViewHierarchyChanged [ui\views\controls\textfield\textfield.cc:433]
~~Dr.M~~ `#17` views::View::ViewHierarchyChangedImpl [ui\views\view.cc:1603]
~~Dr.M~~ `#18` views::View::PropagateAddNotifications [ui\views\view.cc:1561]
~~Dr.M~~ `#19` views::View::AddChildViewAt [ui\views\view.cc:192]
~~Dr.M~~ `#20` views::View::AddChildView [ui\views\view.cc:164]
~~Dr.M~~ `#21` views::GridLayout::AddViewState [ui\views\layout\grid_layout.cc:967]
~~Dr.M~~ `#22` views::GridLayout::AddView [ui\views\layout\grid_layout.cc:757]
~~Dr.M~~ `#23` views::GridLayout::AddView [ui\views\layout\grid_layout.cc:742]
~~Dr.M~~ `#24` views::GridLayout::AddView [ui\views\layout\grid_layout.cc:737]
~~Dr.M~~ `#25` views::GridLayout::AddView [ui\views\layout\grid_layout.cc:730]
~~Dr.M~~ `#26` GenericInfoView::AddRow [chrome\browser\ui\views\generic_info_view.cc:97]
~~Dr.M~~ `#27` GenericInfoView::InitGenericInfoView [chrome\browser\ui\views\generic_info_view.cc:87]
~~Dr.M~~ `#28` GenericInfoView::ViewHierarchyChanged [chrome\browser\ui\views\generic_info_view.cc:47]
~~Dr.M~~ `#29` views::View::ViewHierarchyChangedImpl [ui\views\view.cc:1603]
~~Dr.M~~ `#30` views::View::PropagateAddNotifications [ui\views\view.cc:1561]
~~Dr.M~~ `#31` views::View::AddChildViewAt [ui\views\view.cc:192]
~~Dr.M~~ `#32` views::View::AddChildView [ui\views\view.cc:164]
~~Dr.M~~ `#33` GenericInfoViewTest_GenericInfoView_Test::TestBody [chrome\browser\ui\views\generic_info_view_unittest.cc:35]
~~Dr.M~~ `#34` testing::internal::HandleExceptionsInMethodIfSupportedtesting::Test,void [testing\gtest\src\gtest.cc:2145]
~~Dr.M~~ Note: @0:17:50.808 in thread 2996
~~Dr.M~~ Note: instruction: test 0x24(%esi) $0x08

From the single-bit test I'm assuming this is a bit-level issue.

_Original issue: http://code.google.com/p/drmemory/issues/detail?id=791_