tbh I was a bit sceptical about that previous patch anyways. If I read it correctly, it only tried to not leave stale lock files in some circumstances. Problem with our case is that it might happen while the app is suspended and then OOM killed which means there is no chance for the Qt code to clean it up and it will leave a stale lock file, no matter how clever it tries to be in cleaning them up.
What I think needs to happen is that when the app starts up again (or tries to obtain a lock) it needs to be clever enough to determine that this lock is a stale one from a previous and ignore it. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to qtbase-opensource-src in Ubuntu. https://bugs.launchpad.net/bugs/1576989 Title: stale lock files freeze apps Status in Canonical System Image: Confirmed Status in qtbase-opensource-src package in Ubuntu: Confirmed Status in qtbase-opensource-src package in Ubuntu RTM: New Bug description: Debugging why the Notes app would freeze for some people, I found there were some stale .lock files around. Those .lock files are autocreated by QSettings (with QLockFile) when this file is edited. Problem is, that it sometimes seems to happen that the app is suspended by our lifecycle and then killed (either by closing from spread or OOM killed) and those .lock files stick around. I have implemented a workaround in the notes app[1] to clear up those stale locks when the app starts app, however, today I ran twice in a row into the issue that the very same happened to music app. It would just freeze on startup and never come back. Digging around a bit I found such a stale lock file on its config file which is created with the QML Settings element. This implies that every app using QSettings or QML Settings {} are potentially affected. I suspect many more app freezes can be traced down to this. Now, there is some code in Qt to detect stale lock files [2], however, not sure why it doesn't detect those lock files as stale ones and decides to wait on them forever though. Probably a bug in the code or some of the wrong #ifdefs are triggered for our package builds. [1] https://code.launchpad.net/~mzanetti/reminders-app/remove-stale-lock-files/+merge/293355 [2] http://code.qt.io/cgit/qt/qtbase.git/tree/src/corelib/io/qlockfile_unix.cpp To manage notifications about this bug go to: https://bugs.launchpad.net/canonical-devices-system-image/+bug/1576989/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
