3e0a2239e9
In a following scenario, there could be a crash: 1. Platform: a Windows system with MS Word installed. 2. LibreOffice is run in a listener mode; 3. A Java program opens a Writer document in a visible mode, with an embedded Word OLE object; 4. It adds some text; then resizes the OLE object; then removes the OLE object. Word OLE objects have OLEMISC_RECOMPOSEONRESIZE flag [1]; this means, that every re-layout of the document with this object must ask the OLE server to re-layout the object content. So, the request thread changes the document text, which triggers idle re-layout or redraw; the idles start executing immediately in the idle main thread, with solar mutex locked; then the request thread starts the OLE object removal operation. The ongoing relayout in main thread would at some stage need to execute a call to the OLE object, which temporarily releases the solar mutex (this makes impossible using solar mutex to synchronize the order of operations in this scenario). Other mutexes guarding OLE object (in OleEmbeddedObject, and in OleComponent) are also released for the duration of the call. Thus, the removal that happens in the request thread proceeds, and the node containing the OLE object is destroyed, while the main thread (processing exactly this node) is waiting for the OLE server response, then for mutexes, to proceed. After that, the main thread would attempt to access the destroyed node object. This change introduces a scheduler guard (a RAII object), that sets a flag to not process idle events during the lifetime of the guard. In its constructor, it also makes sure, that current pending idle events are finished. This would make sure that guarded code started from other threads would not race with idles potentially accessing the model that is currently in transient state. [1] https://learn.microsoft.com/en-us/windows/win32/api/oleidl/ne-oleidl-olemisc Change-Id: I2ef0601ccd8b5872588a88493d1f43e39022dbed Reviewed-on: https://gerrit.libreoffice.org/c/core/+/164753 Tested-by: Mike Kaganski <mike.kaganski@collabora.com> Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com> |
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| .. | ||
| qa | ||
| source | ||
| test | ||
| util | ||
| CppunitTest_embeddedobj_general.mk | ||
| CppunitTest_embeddedobj_msole.mk | ||
| IwyuFilter_embeddedobj.yaml | ||
| Library_embobj.mk | ||
| Library_emboleobj.mk | ||
| Makefile | ||
| Module_embeddedobj.mk | ||
| README.md | ||
Embedding Objects Into LibreOffice
Code for embedding objects into LibreOffice (reverse of embedserv module).