SIGSEGV in Channel::writeIntoJson
This happened with 1.9.3 commit 15cfa65e "Add protection according #20 (closed)." Several clients were connected to my server and I don't know what each of them were doing at the time but my server crashed with a SIGSEGV and this stack trace:
(gdb) bt
#0 0x000055555578b754 in Channel::writeIntoJson (this=0x5555564db2f0, json=...) at ../../client/network/channel.cpp:126
#1 0x0000555555785fad in ChannelModel::writeDataJson (this=0x555557d30200, obj=...) at ../../client/network/channelmodel.cpp:617
#2 0x00005555557930b9 in ServerManager::sendOffModel (this=0x555557cf72f0, client=0x7fff84003600) at /usr/include/c++/10/bits/unique_ptr.h:173
#3 0x00005555557960e3 in ServerManager::sendOffModelToAll (this=0x555557cf72f0) at ../../client/network/servermanager.cpp:543
#4 0x00007ffff62d7f21 in QObject::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5 0x00007ffff799e03f in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#6 0x00007ffff62acb62 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7 0x00007ffff62af4c1 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8 0x00007ffff6302c73 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#9 0x00007fffee127bdb in g_main_context_dispatch () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#10 0x00007fffee127e88 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#11 0x00007fffee127f3f in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#12 0x00007ffff63022ff in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#13 0x00007ffff62ab4db in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#14 0x00007ffff60d28de in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#15 0x00007ffff60d3a01 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#16 0x00007fffeeb89ea7 in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
#17 0x00007ffff5c18d4f in clone () from /lib/x86_64-linux-gnu/libc.so.6