Segfault after quitting Mixxx in the "no sound device" selection dialog

[daschuer]

Bug Description

This has append during testing #10989

Here is the backtrace:

Thread 32 "BrowseThread" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fff9a68f700 (LWP 18421)]
0x00007ffff3992e5b in std::__atomic_base<QMutexData*>::compare_exchange_strong
    (__m2=std::memory_order_acquire, __m1=std::memory_order_acquire, __p2=0x1, 
    __p1=<synthetischer Zeiger>: 0x0, this=0x20)
    at /usr/include/c++/9/bits/atomic_base.h:769
769	      compare_exchange_strong(__pointer_type& __p1, __pointer_type __p2,
(gdb) 
(gdb) 
(gdb) bt
#0  0x00007ffff3992e5b in std::__atomic_base<QMutexData*>::compare_exchange_strong(QMutexData*&, QMutexData*, std::memory_order, std::memory_order)
    (__m2=std::memory_order_acquire, __m1=std::memory_order_acquire, __p2=0x1, __p1=<synthetischer Zeiger>: 0x0, this=0x20)
    at /usr/include/c++/9/bits/atomic_base.h:769
#1  std::atomic<QMutexData*>::compare_exchange_strong(QMutexData*&, QMutexData*, std::memory_order, std::memory_order)
    (__m2=std::memory_order_acquire, __m1=std::memory_order_acquire, __p2=0x1, __p1=<synthetischer Zeiger>: 0x0, this=0x20) at /usr/include/c++/9/atomic:565
#2  QAtomicOps<QMutexData*>::testAndSetAcquire<QMutexData*>(std::atomic<QMutexData*>&, QMutexData*, QMutexData*, QMutexData**)
    (currentValue=<synthetischer Zeiger>, newValue=0x1, expectedValue=0x0, _q_value=...) at ../../include/QtCore/../../src/corelib/thread/qatomic_cxx11.h:290
#3  QBasicAtomicPointer<QMutexData>::testAndSetAcquire(QMutexData*, QMutexData*, QMutexData*&)
    (currentValue=<synthetischer Zeiger>: <optimized out>, newValue=0x1, expectedValue=0x0, this=0x20)
    at ../../include/QtCore/../../src/corelib/thread/qbasicatomic.h:263
#4  QBasicMutex::fastTryLock(QMutexData*&)
    (current=<synthetischer Zeiger>: <optimized out>, this=0x20)
    at thread/qmutex.h:107
#5  QMutex::lock() (this=this@entry=0x20) at thread/qmutex.cpp:222
#6  0x00007ffff3c251c4 in QMutexLocker::QMutexLocker(QBasicMutex*)
--Type <RET> for more, q to quit, c to continue without paging--
    (m=0x20, this=<synthetischer Zeiger>)
    at ../../include/QtCore/../../src/corelib/thread/qmutex.h:206
#7  QMimeDatabase::mimeTypeForFile(QFileInfo const&, QMimeDatabase::MatchMode) const
    (this=this@entry=0x7fff9a68dd40, fileInfo=..., mode=mode@entry=QMimeDatabase::MatchContent) at mimetypes/qmimedatabase.cpp:544
#8  0x0000555555b80482 in mixxx::SoundSource::getTypeFromFile(QFileInfo const&)
    (fileInfo=...) at ../../src/sources/soundsource.cpp:56
#9  0x0000555555b80feb in mixxx::SoundSource::getTypeFromUrl(QUrl const&)
    (url=...) at ../../src/sources/soundsource.cpp:30
#10 0x00005555557eabe8 in SoundSourceProxy::allProviderRegistrationsForUrl(QUrl const&) (url=...) at ../../src/sources/soundsourceproxy.cpp:351
#11 0x00005555557ec073 in SoundSourceProxy::SoundSourceProxy(std::shared_ptr<Track>) (this=0x7fff9a68df40, pTrack=...) at ../../src/util/fileinfo.h:32
#12 0x00005555557f0b47 in SoundSourceProxy::importTrackMetadataAndCoverImageFromFile(mixxx::FileAccess, mixxx::TrackMetadata*, QImage*, bool)
    (trackFileAccess=..., pTrackMetadata=pTrackMetadata@entry=0x7fff9a68e290, pCoverImage=pCoverImage@entry=
    0x0, resetMissingTagMetadata=resetMissingTagMetadata@entry=false)
    at /usr/include/c++/9/ext/atomicity.h:96
#13 0x0000555555de5045 in BrowseThread::populateModel() (this=0x55556019ef90)
    at /usr/include/c++/9/bits/atomic_base.h:318
#14 0x0000555555de8c96 in BrowseThread::run() (this=0x55556019ef90)
--Type <RET> for more, q to quit, c to continue without paging--
    at ../../src/library/browse/browsethread.cpp:86
#15 0x00007ffff39929d2 in QThreadPrivate::start(void*) (arg=0x55556019ef90)
    at thread/qthread_unix.cpp:361
#16 0x00007ffff34ca609 in start_thread (arg=<optimized out>)
    at pthread_create.c:477
#17 0x00007ffff33ef133 in clone ()
    at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
(gdb) 

Version

2.4 + #10989

OS

Ubunti 20.4 Focal