Crash on exit

[hebasto]

On master (dbd7a91):

$ lldb ./src/qt/bitcoin-qt -- -testnet
(lldb) target create "./src/qt/bitcoin-qt"
Current executable set to './src/qt/bitcoin-qt' (x86_64).
(lldb) settings set -- target.run-args  "-testnet"
(lldb) run
Process 5006 launched: './src/qt/bitcoin-qt' (x86_64)
Process 5006 stopped
* thread #1, name = 'bitcoin-qt', stop reason = signal SIGSEGV: invalid address (fault address: 0x38)
    frame #0: 0x00007ffff72e1fa0 libpthread.so.0`__GI___pthread_mutex_lock
libpthread.so.0`__GI___pthread_mutex_lock:
->  0x7ffff72e1fa0 <+0>:  movl   0x10(%rdi), %eax
    0x7ffff72e1fa3 <+3>:  movl   %eax, %edx
    0x7ffff72e1fa5 <+5>:  andl   $0x17f, %edx              ; imm = 0x17F 
    0x7ffff72e1fab <+11>: nop    
(lldb) bt
error: bitcoin-qt :: Class 'ClientModel' has a base class 'QObject' which does not have a complete definition.
error: bitcoin-qt :: Try compiling the source file with -fstandalone-debug.
* thread #1, name = 'bitcoin-qt', stop reason = signal SIGSEGV: invalid address (fault address: 0x38)
  * frame #0: 0x00007ffff72e1fa0 libpthread.so.0`__GI___pthread_mutex_lock
    frame #1: 0x00005555555ea443 bitcoin-qt`ClientModel::getBestBlockHash() [inlined] __gthread_mutex_lock(__mutex=0x0000000000000028) at gthr-default.h:748
    frame #2: 0x00005555555ea43b bitcoin-qt`ClientModel::getBestBlockHash() [inlined] std::mutex::lock(this=0x0000000000000028) at std_mutex.h:103
    frame #3: 0x00005555555ea42d bitcoin-qt`ClientModel::getBestBlockHash() [inlined] std::unique_lock<std::mutex>::lock(this=<unavailable>) at std_mutex.h:267
    frame #4: 0x00005555555ea42d bitcoin-qt`ClientModel::getBestBlockHash() [inlined] UniqueLock<AnnotatedMixin<std::mutex>, std::unique_lock<std::mutex> >::Enter(this=<unavailable>, pszFile=<unavailable>, nLine=119) at sync.h:139
    frame #5: 0x00005555555ea42d bitcoin-qt`ClientModel::getBestBlockHash() [inlined] UniqueLock<AnnotatedMixin<std::mutex>, std::unique_lock<std::mutex> >::UniqueLock(this=<unavailable>, mutexIn=0x0000000000000028, pszFile=<unavailable>, nLine=119, fTry=false) at sync.h:160
    frame #6: 0x00005555555ea42d bitcoin-qt`ClientModel::getBestBlockHash() [inlined] ClientModel::getBestBlockHash(this=<unavailable>)::$_2::operator()() const at clientmodel.cpp:119
    frame #7: 0x00005555555ea42d bitcoin-qt`ClientModel::getBestBlockHash(this=0x0000000000000000) at clientmodel.cpp:119
    frame #8: 0x00005555556a23f6 bitcoin-qt`TransactionTableModel::index(this=0x0000555556472cf0, row=11, column=4, parent=<unavailable>) const at transactiontablemodel.cpp:667
    frame #9: 0x00007ffff5a9c5e9 libQt5Core.so.5`___lldb_unnamed_symbol1919$$libQt5Core.so.5 + 249
    frame #10: 0x00007ffff5a9cb56 libQt5Core.so.5`QSortFilterProxyModel::flags(QModelIndex const&) const + 166
    frame #11: 0x00007ffff6adf3c5 libQt5Widgets.so.5`QListView::moveCursor(QAbstractItemView::CursorAction, QFlags<Qt::KeyboardModifier>) + 437
    frame #12: 0x00007ffff6aad083 libQt5Widgets.so.5`QAbstractItemView::focusInEvent(QFocusEvent*) + 259
    frame #13: 0x00007ffff68987ff libQt5Widgets.so.5`QWidget::event(QEvent*) + 2479
    frame #14: 0x00007ffff69394de libQt5Widgets.so.5`QFrame::event(QEvent*) + 30
    frame #15: 0x00007ffff6942623 libQt5Widgets.so.5`QAbstractScrollArea::event(QEvent*) + 899
    frame #16: 0x00007ffff6aac87b libQt5Widgets.so.5`QAbstractItemView::event(QEvent*) + 187
    frame #17: 0x00007ffff685983c libQt5Widgets.so.5`QApplicationPrivate::notify_helper(QObject*, QEvent*) + 156
    frame #18: 0x00007ffff6861104 libQt5Widgets.so.5`QApplication::notify(QObject*, QEvent*) + 676
    frame #19: 0x00007ffff5adb8d8 libQt5Core.so.5`QCoreApplication::notifyInternal2(QObject*, QEvent*) + 280
    frame #20: 0x00007ffff685ecbe libQt5Widgets.so.5`QApplicationPrivate::setFocusWidget(QWidget*, Qt::FocusReason) + 526
    frame #21: 0x00007ffff68927ef libQt5Widgets.so.5`QWidget::setFocus(Qt::FocusReason) + 415
    frame #22: 0x00007ffff685f14b libQt5Widgets.so.5`QApplication::setActiveWindow(QWidget*) + 1067
    frame #23: 0x00007ffff685f243 libQt5Widgets.so.5`QApplicationPrivate::notifyActiveWindowChange(QWindow*) + 51
    frame #24: 0x00007ffff609eee5 libQt5Gui.so.5`QGuiApplicationPrivate::processActivatedEvent(QWindowSystemInterfacePrivate::ActivatedWindowEvent*) + 789
    frame #25: 0x00007ffff609f14d libQt5Gui.so.5`QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) + 557
    frame #26: 0x00007ffff60762eb libQt5Gui.so.5`QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 171
    frame #27: 0x00007fffecd98260 libQt5XcbQpa.so.5`___lldb_unnamed_symbol984$$libQt5XcbQpa.so.5 + 16
    frame #28: 0x00007ffff19d5417 libglib-2.0.so.0`g_main_context_dispatch + 743
    frame #29: 0x00007ffff19d5650 libglib-2.0.so.0`___lldb_unnamed_symbol192$$libglib-2.0.so.0 + 512
    frame #30: 0x00007ffff19d56dc libglib-2.0.so.0`g_main_context_iteration + 44
    frame #31: 0x00007ffff5b3488f libQt5Core.so.5`QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 95
    frame #32: 0x00007ffff5ad990a libQt5Core.so.5`QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) + 314
    frame #33: 0x00007ffff5ae29b4 libQt5Core.so.5`QCoreApplication::exec() + 148
    frame #34: 0x00005555555d2985 bitcoin-qt`GuiMain(argc=<unavailable>, argv=<unavailable>) at bitcoin.cpp:594
    frame #35: 0x00005555555cea43 bitcoin-qt`main(argc=<unavailable>, argv=<unavailable>) at main.cpp:21
    frame #36: 0x00007ffff3c7db97 libc.so.6`__libc_start_main(main=(bitcoin-qt`main at main.cpp:21), argc=2, argv=0x00007fffffffdcf8, init=<unavailable>, fini=<unavailable>, rtld_fini=<unavailable>, stack_end=0x00007fffffffdce8) at libc-start.c:310
    frame #37: 0x00005555555ce96a bitcoin-qt`_start + 42

[maflcko]

Does this also happen on the latest release?

[hebasto]

Does this also happen on the latest release?

No. Tracked until bitcoin/bitcoin#19132. The regression happened before it.

[maflcko]

Is there any commit that works?

[hebasto]

Is there any commit that works?

f4b603c works fine.

[hebasto]

@MarcoFalke

Is there any commit that works?

This crash is not reliably reproducible. I've observed it three times only:

• the first time on master without debugger
• the second time on master (dbd7a91) in lldb, see OP
• the third time on f4f2220 in lldb

[hebasto]

cc @vasild

[promag]

ClientModel::getBestBlockHash(this=0x0000000000000000) 👀

[hebasto]

The results of the commit digging.

The regression was supposedly introduced in bitcoin/bitcoin#17993.

Steps to reproduce:

• precondition: the old chain
• start bitcoin-qt
• wait until sync
• on main window: Menu -> File -> Quit
• crash

[ryanofsky]

re: #7 (comment)

ClientModel::getBestBlockHash(this=0x0000000000000000)

From stack trace, call happens on this line:

gui/src/qt/transactiontablemodel.cpp

Line 667 in dbd7a91

TransactionRecord* data = priv->index(walletModel->wallet(), walletModel->clientModel().getBestBlockHash(), row);

As a minimal fix, walletModel->clientModel().getBestBlockHash() here could be replaced by a more direct walletMode->getLastBlockProcessed() call. This method could be implemented to either return m_cached_last_update_tip to go back to pre-#17993 behavior or return m_client_model ? m_client_model->getBestBlockHash() : uint256{} to keep the current behavior but avoid crashing.

Review comment bitcoin/bitcoin#17993 (comment) describes differences between two behaviors and also what ideal behavior would be.

[hebasto]

@ryanofsky Thank you Russ! Mind looking into #8?