[Qt] Crash when connecting Switch Pro Controller via USB

[Parnassius]

Steps to reproduce

• Connect a Nintendo Switch Pro Controller via Bluetooth
• Open mGBA
• Go to Tools -> Settings -> Controllers, and make sure 'Pro Controller' is selected (might not be required, not sure)
• Connect the controller to the pc with a USB-C cable
• mGBA crashes after a few seconds

This always happens, both with and without a game loaded.

OS:

• Debian 10 x86-64, mGBA 0.8-b1, 0.7.3, 0.7.2, 0.7.1, 0.7.0
• Ubuntu 19.10 x86-64, mGBA 0.7.0

[endrift]

This appears to have already been fixed in the dev builds, so it should be fine in 0.8.0 final when that comes out.

[Parnassius]

I just built master (6ae02d0) and it still crashes, should I try a different branch?

Anyway here's the backtrace given by the KDE crash handler, not sure if it helps:

Application: mgba-qt (mgba-qt), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fd4867a9cc0 (LWP 8551))]

Thread 5 (Thread 0x7fd475cb2700 (LWP 8556)):
#0  futex_wait_cancelable (private=0, expected=0, futex_word=0x5614cdaa4dc8) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x5614cdaa4d78, cond=0x5614cdaa4da0) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=cond@entry=0x5614cdaa4da0, mutex=mutex@entry=0x5614cdaa4d78) at pthread_cond_wait.c:655
#3  0x00007fd476be2e03 in cnd_wait (mtx=0x5614cdaa4d78, cond=0x5614cdaa4da0) at ../src/../include/c11/threads_posix.h:155
#4  util_queue_thread_func (input=input@entry=0x5614cda4e300) at ../src/util/u_queue.c:270
#5  0x00007fd476be2b57 in impl_thrd_routine (p=<optimized out>) at ../src/../include/c11/threads_posix.h:87
#6  0x00007fd48c4effa3 in start_thread (arg=<optimized out>) at pthread_create.c:486
#7  0x00007fd48b0204cf in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x7fd4765f4700 (LWP 8555)):
#0  futex_wait_cancelable (private=0, expected=0, futex_word=0x5614cd9cdf58) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x5614cd9cdf08, cond=0x5614cd9cdf30) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=cond@entry=0x5614cd9cdf30, mutex=mutex@entry=0x5614cd9cdf08) at pthread_cond_wait.c:655
#3  0x00007fd476be2e03 in cnd_wait (mtx=0x5614cd9cdf08, cond=0x5614cd9cdf30) at ../src/../include/c11/threads_posix.h:155
#4  util_queue_thread_func (input=input@entry=0x5614cdc3a670) at ../src/util/u_queue.c:270
#5  0x00007fd476be2b57 in impl_thrd_routine (p=<optimized out>) at ../src/../include/c11/threads_posix.h:87
#6  0x00007fd48c4effa3 in start_thread (arg=<optimized out>) at pthread_create.c:486
#7  0x00007fd48b0204cf in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7fd47f12c700 (LWP 8553)):
#0  0x00007fd48b015819 in __GI___poll (fds=0x7fd478004db0, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fd489b21136 in g_main_context_poll (priority=<optimized out>, n_fds=1, fds=0x7fd478004db0, timeout=<optimized out>, context=0x7fd478000bf0) at ../../../glib/gmain.c:4221
#2  g_main_context_iterate (context=context@entry=0x7fd478000bf0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../glib/gmain.c:3915
#3  0x00007fd489b2125c in g_main_context_iteration (context=0x7fd478000bf0, may_block=may_block@entry=1) at ../../../glib/gmain.c:3981
#4  0x00007fd48b6c67b3 in QEventDispatcherGlib::processEvents (this=0x7fd478000b20, flags=...) at kernel/qeventdispatcher_glib.cpp:424
#5  0x00007fd48b6741cb in QEventLoop::exec (this=this@entry=0x7fd47f12bd30, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:140
#6  0x00007fd48b4c3e96 in QThread::exec (this=this@entry=0x7fd4862d0d60 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at ../../include/QtCore/../../src/corelib/global/qflags.h:120
#7  0x00007fd486251545 in QDBusConnectionManager::run (this=0x7fd4862d0d60 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at qdbusconnection.cpp:178
#8  0x00007fd48b4cda87 in QThreadPrivate::start (arg=0x7fd4862d0d60 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread_unix.cpp:367
#9  0x00007fd48c4effa3 in start_thread (arg=<optimized out>) at pthread_create.c:486
#10 0x00007fd48b0204cf in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7fd485999700 (LWP 8552)):
#0  0x00007fd48b015819 in __GI___poll (fds=fds@entry=0x7fd485998c78, nfds=nfds@entry=1, timeout=timeout@entry=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fd4899b8cf7 in poll (__timeout=-1, __nfds=1, __fds=0x7fd485998c78) at /usr/include/x86_64-linux-gnu/bits/poll2.h:46
#2  _xcb_conn_wait (c=c@entry=0x5614cd8421a0, cond=cond@entry=0x5614cd8421e0, vector=vector@entry=0x0, count=count@entry=0x0) at ../../src/xcb_conn.c:479
#3  0x00007fd4899ba91a in xcb_wait_for_event (c=0x5614cd8421a0) at ../../src/xcb_in.c:697
#4  0x00007fd48635ed79 in QXcbEventReader::run (this=0x5614cd84c970) at qxcbconnection.h:409
#5  0x00007fd48b4cda87 in QThreadPrivate::start (arg=0x5614cd84c970) at thread/qthread_unix.cpp:367
#6  0x00007fd48c4effa3 in start_thread (arg=<optimized out>) at pthread_create.c:486
#7  0x00007fd48b0204cf in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7fd4867a9cc0 (LWP 8551)):
[KCrash Handler]
#6  __strncmp_avx2 () at ../sysdeps/x86_64/multiarch/strcmp-avx2.S:101
#7  0x00007fd48ccd3a97 in SDL_FixupJoystickName (name=0x101070001030101 <error: Cannot access memory at address 0x101070001030101>) at ./src/joystick/SDL_joystick.c:203
#8  0x00005614cbda8be4 in QGBA::InputController::updateJoysticks() ()
#9  0x00007fd48b69e9a3 in QtPrivate::QSlotObjectBase::call (a=0x7ffc909a0be0, r=0x5614cd8f3058, this=0x5614cdb59ee0) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:376
#10 QMetaObject::activate (sender=0x5614cd8f3058, signalOffset=<optimized out>, local_signal_index=<optimized out>, argv=<optimized out>) at kernel/qobject.cpp:3754
#11 0x00007fd48b6aa3f7 in QTimer::timeout (this=<optimized out>, _t1=...) at .moc/moc_qtimer.cpp:200
#12 0x00007fd48b69f09b in QObject::event (this=0x5614cd8f3058, e=<optimized out>) at kernel/qobject.cpp:1232
#13 0x00007fd48bff04c1 in QApplicationPrivate::notify_helper (this=this@entry=0x5614cd8318d0, receiver=receiver@entry=0x5614cd8f3058, e=e@entry=0x7ffc909a0eb0) at kernel/qapplication.cpp:3726
#14 0x00007fd48bff7970 in QApplication::notify (this=0x7ffc909a12b0, receiver=0x5614cd8f3058, e=0x7ffc909a0eb0) at kernel/qapplication.cpp:3485
#15 0x00007fd48b6754f9 in QCoreApplication::notifyInternal2 (receiver=0x5614cd8f3058, event=event@entry=0x7ffc909a0eb0) at ../../include/QtCore/5.11.3/QtCore/private/../../../../../src/corelib/thread/qthread_p.h:307
#16 0x00007fd48b6c5ba8 in QCoreApplication::sendEvent (event=0x7ffc909a0eb0, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:234
#17 QTimerInfoList::activateTimers (this=0x5614cd891e80) at kernel/qtimerinfo_unix.cpp:643
#18 0x00007fd48b6c643c in timerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:182
#19 idleTimerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:229
#20 0x00007fd489b20f2e in g_main_dispatch (context=0x7fd480004ff0) at ../../../glib/gmain.c:3182
#21 g_main_context_dispatch (context=context@entry=0x7fd480004ff0) at ../../../glib/gmain.c:3847
#22 0x00007fd489b211c8 in g_main_context_iterate (context=context@entry=0x7fd480004ff0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../glib/gmain.c:3920
#23 0x00007fd489b2125c in g_main_context_iteration (context=0x7fd480004ff0, may_block=may_block@entry=1) at ../../../glib/gmain.c:3981
#24 0x00007fd48b6c6797 in QEventDispatcherGlib::processEvents (this=0x5614cd89dd70, flags=...) at kernel/qeventdispatcher_glib.cpp:422
#25 0x00007fd4863f5401 in QPAEventDispatcherGlib::processEvents (this=0x5614cd89dd70, flags=...) at qeventdispatcher_glib.cpp:69
#26 0x00007fd48b6741cb in QEventLoop::exec (this=this@entry=0x7ffc909a1130, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:140
#27 0x00007fd48b67c1a2 in QCoreApplication::exec () at ../../include/QtCore/../../src/corelib/global/qflags.h:120
#28 0x00005614cbd5a26b in main ()
[Inferior 1 (process 8551) detached]

Thanks for your time!

[endrift]

Strange, it didn't crash for me when I tried master but it did crash with 0.8-b1. I'll see if I can fix this blind.

[endrift]

I managed to reproduce it with the same backtrace, so it should be fixed for real this time.