Crash in QEventDispatcherUNIX with Qt 5.8 on OSX

[nirslsk]

Hi there,

I have a peer-to-peer application written using Qt that's been out there for several years now. A couple of users have reported a crash that looks like this:

Thread 10 Crashed:
0 libsystem_kernel.dylib 0x00007fffbfdf2dd6 __pthread_kill + 10
1 libsystem_pthread.dylib 0x00007fffbfede787 pthread_kill + 90
2 libsystem_c.dylib 0x00007fffbfd58420 abort + 129
3 org.qt-project.QtCore 0x0000000105a468c9 0x105a30000 + 92361
4 org.qt-project.QtCore 0x0000000105a48297 QMessageLogger::fatal(char const*, ...) const + 231
5 org.qt-project.QtCore 0x0000000105c6ef3f QEventDispatcherUNIXPrivate::QEventDispatcherUNIXPrivate() + 527
6 org.qt-project.QtCore 0x0000000105c6f6d5 QEventDispatcherUNIX::QEventDispatcherUNIX(QObject*) + 37
7 org.qt-project.QtCore 0x0000000105a5a6c3 0x105a30000 + 173763
8 org.qt-project.QtCore 0x0000000105a5a7d3 0x105a30000 + 174035
9 libsystem_pthread.dylib 0x00007fffbfedbaab _pthread_body + 180
10 libsystem_pthread.dylib 0x00007fffbfedb9f7 _pthread_start + 286
11 libsystem_pthread.dylib 0x00007fffbfedb1fd thread_start + 13

They're both on OSX and at least one of them is using a Qt 5.8 build. I ran a couple of google searches and found some information about the possibility that the operating system is running out of file descriptors. That seems possible since the app is very socket-heavy, and can sometimes create hundreds of TCP connections simultaneously. I asked one of these users to change the maximum file descriptor limit and see if it's still happening, but I figured I'd post about it here in the meantime in case someone knows anything about this. Any help would be appreciated.

Thanks, Nir

[kshegunov]

Hard to tell as some of the calls are optimized out. By the way what does the message say (you should get one on the standard output from the QMessageLogger::fatal call?