I finally took the time to investigate the plasma crash that was happening so often to me.
Almost reproduceable testcase: 4.3 branch, enable task grouping, have some grouping in one desktop, then hit the "next desktop" key shortcut like a mad man (but at varying speeds) until it crashes. Well... last week this was quite reproduceable this way. This week I can't do it that way, I can only use kde and wait until it crashes again. Weird. Anyway. As suspected from the start, the problem was in the "task group item" code, and timing-related (so the "deleteLater" looked suspicious), but my earlier backtraces weren't really enough to figure out the problem. Now after valgrind'ing and adding tons of kDebug, I found the problem. It's a race between the "deleteLater" and the actual deletion. In between those two events, the item is re-added to the layout. So just after the actual deletion takes place, we have a dangling pointer in the layout's m_itemPositions list. TaskGroupItem::itemRemoved: groupItem= 0x202db80 item= 0x3a48370 m_tasksLayout= 0x202e6a0 TaskItemLayout::remove: this= 0x202e6a0 removing AbstractTaskItem 0x3a48370 TaskGroupItem::itemRemoved: Calling deleteLater on item 0x3a48370 m_applet= 0x1d07380 [...] QGraphicsScene::removeItem: item 0x3a48380's scene (0x0) is different from this scene (0x19e80d0) << interesting, a QGraphicsScene warning too TaskItemLayout::insert: this= 0x202e6a0 inserting item 0x3a48370 into m_itemPositions TaskItemLayout::preferredColumns: 0x202e6a0 First AbstractTaskItem in m_itemPositions: 0x3a48370 [...] [then the deleteLater kicks in] WindowTaskItem::~WindowTaskItem: 0x3a48370 AbstractTaskItem::~AbstractTaskItem: Deleting taskitem 0x3a48370 m_applet= 0x1d07380 TaskItemLayout::preferredColumns: 0x202e6a0 First AbstractTaskItem in m_itemPositions: 0x3a48370 AbstractTaskItem::basicPreferredSize: 0x3a48370 CRASH. (0x3a48370 is a dangling pointer to a deleted item) The only part that is not clear to me is where the insert() comes from, but maybe you guys know that part anyway? Any ideas? PS: please CC me on replies. -- David Faure, fa...@kde.org, sponsored by Nokia to work on KDE, Konqueror (http://www.konqueror.org), and KOffice (http://www.koffice.org). _______________________________________________ Plasma-devel mailing list Plasma-devel@kde.org https://mail.kde.org/mailman/listinfo/plasma-devel
