Hi Tim, I've tried your patch, unfortunately the client still has crash issue. However, this time the only error message is "A/libc? Fatal signal 6 (SIGABRT), code -6 in tid 11352 (FinalizerDaemon)", without any stack trace and JNI exception details. Do you have any idea about this kind of message? Also I'm curious about why simply set weak reference to a nullptr can solve this issue? When the object is released, the weak reference is supposed to reference to a null pointer, and I also tried using IsSameObject to verify it. However, the operation is aborted by ART runtime.
Best Regard, === Yu-Hsin Hung, Intern, Mediatek Graduate Student, Institute of Computer Science and Engineering, National Chiao-Tung Universiry, Hsinchu 300, Taiwan (Phone) +886911012113 (Email) hungys at hotmail.com (LinkedIn) https://www.linkedin.com/in/hungys === From: [email protected] To: hungys at hotmail.com; iotivity-dev at lists.iotivity.org Subject: RE: [dev] Android JNI OnEventListener crash Date: Thu, 27 Aug 2015 21:56:32 +0000 Hi Yu-Hsin, The most probable cause of this crash is OcResource object going out of scope before all of the GET responses have been received by a client side. This patch should help to make things a bit more robust: https://gerrit.iotivity.org/gerrit/#/c/2306/ In general, I would recommend using ?observe? capability instead of the constant polling, unless your server doesn?t support it. Thanks, Tim From: iotivity-dev-bounces at lists.iotivity.org [mailto:[email protected]] On Behalf Of Yu-Hsin Hung Sent: Tuesday, August 18, 2015 6:57 AM To: iotivity-dev at lists.iotivity.org Subject: [dev] Android JNI OnEventListener crash Dear devs, Recently I found that when Android client sends GET request to server frequently (e.g. polling), there will be random crashes due to JNI level being aborted. The exception basically says the native code try to access deleted weak global reference. After tracing the implementation, I found that the event listener for GET/POST/PUT/? is stored as weak global references, which means they may be released by JVM GC on demand and then cause the crashes. iotivity/android/android_api/base/jni/JniOnGetListener.cpp jobject jListener = env->NewLocalRef(m_jwListener); In the above code, the m_jwListener is a weak global reference, so it may be deleted by GC before this line called. But it seems the ART runtime didn?t return NULL as expected, but aborting the execution. Even if I try to modify them as global reference using NewGlobalRef at the constructer of JniOnGetListener (as following), sometimes the crash still occurs. iotivity/android/android_api/base/jni/JniOnGetListener.h jweak m_jwListener; iotivity/android/android_api/base/jni/JniOnGetListener.cpp m_jwListener = env->NewWeakGlobalRef(jListener); The error log is attached. Does anyone notice this issue? or any idea to fix it? Thanks! Best Regard, === Yu-Hsin Hung, Intern, Mediatek Graduate Student, Institute of Computer Science and Engineering, National Chiao-Tung Universiry, Hsinchu 300, Taiwan (Phone) +886911012113 (Email) hungys at hotmail.com (LinkedIn) https://www.linkedin.com/in/hungys === -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.iotivity.org/pipermail/iotivity-dev/attachments/20150828/4cb24028/attachment.html>
