Details
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Bug
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Resolution: Won't Do
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P2: Important
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None
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5.11, 5.12.0, 5.12.1, 5.12.2, 5.12.3
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None
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Google Pixelbook
Stable Channel ChromeOS 73.3683.114
Android 9
Description
Although this behavior doesn't occur on Android 9.0 using the Android-Studio x86 Android 9.0 emulators Nexus_5X_API_28_x86 or Android_TV_1080p_API_28, on a Google Pixelbook running Android 9.0, I get a consistent crash if compiling with "Android for x86 (Clang Qt5.12.3 for Android X86). The same exact app compiled for armeabi-v7a (Clang Qt 5.12.3 for Android ARMv7) does not crash on the Pixelbook(NB: Projects->Build and Run indicates this arch doesn't employ QML compiler). Thus, the problem comes only using the native X86 Android compile (Pixelbook uses Intel core x86), not when the Pixelbook emulates ARMv7 apps for android-back compatibility.
The crash is triggered as follows: If the QML MediaPlayer is playing back audio and/or some kind of UI activity is going on in response to the audio playing (e.g. displaying elapsed time) the application will crash on minimization with following output:
F libc : Fatal signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x4 in tid 5075 (QtThread), pid 5040 (_visualizer_qml)
The above output occurs from running example app https://doc.qt.io/qt-5/qt3d-audio-visualizer-qml-example.html which employs QML MediaPlayer for audio playback. This app is mentioned as a public example which triggers the crash, but any application using QML MediaPlayer on the Pixelbook has the same problem. Note that if the media is not loaded and/or not playing-back in MediaPlayer, the crash is not triggered on minimization.
To eliminate any other issues from arising through use of older android API, I forced build of this example to Android API 28. (see https://bugreports.qt.io/browse/QTBUG-71590?focusedCommentId=456781&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-456781
https://bugreports.qt.io/browse/QTBUG-71590?focusedCommentId=456782&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-456782
https://bugreports.qt.io/browse/QTBUG-71590?focusedCommentId=456822&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-456822 ).
Also note that the problematic Pixelbook behavior changed through several releases.
I believe that in Qt5.11, 5.12, 5.12.1, 5.12.2 the behavior was buggy in that a QML MediaPlayer using application would not crash on minimize, but rather that the app would stay around in a "zombie" state on termination, preventing re-launch until the app was explicitly killed via settings->apps... In 5.12.3 the new behavior was noticed where the app would crash on minimize, but would not persist in a zombie state after exit.
I will attach full output of the crashing x86 "audio visualizer" example from Qt 5.12.3.
Note that backtrace produces no useful debug information – seems like the crash is occurring deep in Android and not in the app or Qt code?