[Konsole-devel] [konsole] [Bug 345294] New: Hang in exiting konsole with Ctrl+D with QInputMethodQuery

[Takahiro Hashimoto]

https://bugs.kde.org/show_bug.cgi?id=345294

            Bug ID: 345294
           Summary: Hang in exiting konsole with Ctrl+D with
                    QInputMethodQuery
           Product: konsole
           Version: 3.90.900
          Platform: Compiled Sources
                OS: Linux
            Status: UNCONFIRMED
          Severity: crash
          Priority: NOR
         Component: general
          Assignee: konsole-devel at kde.org
          Reporter: kenya888 at gmail.com
                CC: kurt.hindenburg at gmail.com

Created attachment 91614
  --> https://bugs.kde.org/attachment.cgi?id=91614&action=edit
a patch to fix konsole hang when exiting

[ Environment ]
 - Fedora 21 or Gentoo
 - Kernel 3.18/3.19
 - gcc 4.8.3/4.9.2
 - Qt 5.4.1(build from git repo)
 - KF5 latest(build with kdesrc-build)
 - konsole (commit 9f8d3933940744cf8eca50d57558bfac82eb0ee7)

[ How to reproduce ]
 - Launch Konsole
 - Operate some work
 - Exit with Ctrl+D(quit bash)

[ Expected behavior ]
 - Konsole exits gracefully

[ Fact behavior ]
 - Konsole hangs (not crash)

[ Frequency of occurrence ]
 - very often

[Additional info]
 - I use qimsys(http://git.qtquick.me/?p=qimsys.git;a=summary), Japanese input
method written with Qt and qimsys requests QInputMethodQueryEvent to Konsole

[Solution]
 - proposed a patch (see attached)

[Investigation]

I have found missing incrementation of for loop around
"src/TerminalCharacterDecoder.cpp:114"

backtrace: 
(gdb) bt
#0  0x00007fca51bee939 in QHash<unsigned short, unsigned
short*>::value(unsigned short const&) const (this=0x7fca51ea1790
<Konsole::ExtendedCharTable::instance>, akey=@0x7ffcc0680f14: 42168) at
/opt/qt/5.4/include/QtCore/qhash.h:615
#1  0x00007fca51bee379 in QHash<unsigned short, unsigned
short*>::operator[](unsigned short const&) const (this=0x7fca51ea1790
<Konsole::ExtendedCharTable::instance>, akey=@0x7ffcc0680f14: 42168) at
/opt/qt/5.4/include/QtCore/qhash.h:743
Python Exception <type 'exceptions.RuntimeError'> maximum recursion depth
exceeded: 
#2  0x00007fca51beda71 in
Konsole::ExtendedCharTable::lookupExtendedChar(unsigned short, unsigned short&)
const (this=0x7fca51ea1790 <Konsole::ExtendedCharTable::instance>, hash=42168,
length=@0x7ffcc0680f6a: 0) at
/home/thashimo/devel/kf5/src/kde/applications/konsole/src/ExtendedCharTable.cpp:118
#3  0x00007fca51bec202 in
Konsole::PlainTextDecoder::decodeLine(Konsole::Character const*, int, unsigned
char) (this=0x7ffcc0680fe0, characters=0xb0e2a0, count=155)
    at
/home/thashimo/devel/kf5/src/kde/applications/konsole/src/TerminalCharacterDecoder.cpp:114
#4  0x00007fca51bfc04f in
Konsole::TerminalDisplay::inputMethodQuery(Qt::InputMethodQuery) const
(this=0x9def90, query=Qt::ImSurroundingText)
    at
/home/thashimo/devel/kf5/src/kde/applications/konsole/src/TerminalDisplay.cpp:2913
#5  0x00007fca4c5d1dc1 in QWidget::event(QEvent*) (this=0x9def90,
event=0x7ffcc0681b30) at
/home/thashimo/devel/qt5/qtbase/src/widgets/kernel/qwidget.cpp:8739
#6  0x00007fca51bfc9fd in Konsole::TerminalDisplay::event(QEvent*)
(this=0x9def90, event=0x7ffcc0681b30)
    at
/home/thashimo/devel/kf5/src/kde/applications/konsole/src/TerminalDisplay.cpp:3120
#7  0x00007fca4c582408 in QApplicationPrivate::notify_helper(QObject*, QEvent*)
(this=0x6c0420, receiver=0x9def90, e=0x7ffcc0681b30)
    at /home/thashimo/devel/qt5/qtbase/src/widgets/kernel/qapplication.cpp:3722


(gdb) f 0
#0  0x00007fca51bee939 in QHash<unsigned short, unsigned short*>::value
(this=0x7fca51ea1790 <Konsole::ExtendedCharTable::instance>,
akey=@0x7ffcc0680f14: 42168)
    at /opt/qt/5.4/include/QtCore/qhash.h:615
615    Q_INLINE_TEMPLATE const T QHash<Key, T>::value(const Key &akey) const
(gdb) f 1 
#1  0x00007fca51bee379 in QHash<unsigned short, unsigned short*>::operator[]
(this=0x7fca51ea1790 <Konsole::ExtendedCharTable::instance>,
akey=@0x7ffcc0680f14: 42168)
    at /opt/qt/5.4/include/QtCore/qhash.h:743
743        return value(akey);
(gdb) f 2 
Python Exception <type 'exceptions.RuntimeError'> maximum recursion depth
exceeded: 
#2  0x00007fca51beda71 in Konsole::ExtendedCharTable::lookupExtendedChar
(this=0x7fca51ea1790 <Konsole::ExtendedCharTable::instance>, hash=42168, 
    length=@0x7ffcc0680f6a: 0) at
/home/thashimo/devel/kf5/src/kde/applications/konsole/src/ExtendedCharTable.cpp:118
118        ushort* buffer = extendedCharTable[hash];
(gdb) down
#1  0x00007fca51bee379 in QHash<unsigned short, unsigned short*>::operator[]
(this=0x7fca51ea1790 <Konsole::ExtendedCharTable::instance>,
akey=@0x7ffcc0680f14: 42168)
    at /opt/qt/5.4/include/QtCore/qhash.h:743
743        return value(akey);
(gdb) up
Python Exception <type 'exceptions.RuntimeError'> maximum recursion depth
exceeded: 
#2  0x00007fca51beda71 in Konsole::ExtendedCharTable::lookupExtendedChar
(this=0x7fca51ea1790 <Konsole::ExtendedCharTable::instance>, hash=42168, 
    length=@0x7ffcc0680f6a: 0) at
/home/thashimo/devel/kf5/src/kde/applications/konsole/src/ExtendedCharTable.cpp:118
118        ushort* buffer = extendedCharTable[hash];
(gdb) up
#3  0x00007fca51bec202 in Konsole::PlainTextDecoder::decodeLine
(this=0x7ffcc0680fe0, characters=0xb0e2a0, count=155)
    at
/home/thashimo/devel/kf5/src/kde/applications/konsole/src/TerminalCharacterDecoder.cpp:114
114                const ushort* chars =
ExtendedCharTable::instance.lookupExtendedChar(characters[i].character,
extendedCharLength);
(gdb) list
109        }
110    
111        for (int i = 0; i < outputCount;) {
112            if (characters[i].rendition & RE_EXTENDED_CHAR) {
113                ushort extendedCharLength = 0;
114                const ushort* chars =
ExtendedCharTable::instance.lookupExtendedChar(characters[i].character,
extendedCharLength);
115                if (chars) {
116                    const QString s = QString::fromUtf16(chars,
extendedCharLength);
117                    plainText.append(s);
118                    i += qMax(1, string_width(s));
(gdb) list
119                }
120            } else {
121                // All characters which appear before the last real
character are
122                // seen as real characters, even when they are technically
marked as
123                // non-real.
124                //
125                // This feels tricky, but otherwise leading "whitespaces"
may be
126                // lost in some situation. One typical example is copying
the result
127                // of `dialog --infobox "qwe" 10 10` .
128                if (characters[i].isRealCharacter || i <=
realCharacterGuard) {

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