[Interest] QSqlDatabase segfault - me or Qt5?

[Scott Aron Bloom]

Quick question, any chance any of this is multi-threaded?

-----Original Message-----
From: interest-bounces+scott.bloom=onshorecs.com at qt-project.org [mailto:interest-bounces+scott.bloom=onshorecs.com at qt-project.org] On Behalf Of bill.king at nokia.com
Sent: Monday, March 04, 2013 1:50 AM
To: list at qtrac.plus.com; interest at qt-project.org
Subject: Re: [Interest] QSqlDatabase segfault - me or Qt5?

Not enough info in the backtrace. Hrm. I did see this many years ago, but I can't remember what caused it. Some form of being a bit too smart for my own good I suspect ;)

Exact line in the destructor could help. Are you deriving from the QSqlDatabase class? Or maybe holding a pointer to a deleted copy? Maybe a valgrind --tool=memcheck run may shed some light.

--

    Bill King
    Test Engineer
    Nokia, Guidance Team


> -----Original Message-----
> From: interest-bounces+bill.king=nokia.com at qt-project.org
> [mailto:interest-bounces+bill.king=nokia.com at qt-project.org] On Behalf 
> Of ext Mark Summerfield
> Sent: Friday, 1 March 2013 3:24 PM
> To: interest at qt-project.org
> Subject: [Interest] QSqlDatabase segfault - me or Qt5?
> Importance: High
> 
> Hi,
> 
> I've got a release version of Qt that's giving this on 64-bit linux:
> 
> Program received signal SIGSEGV, Segmentation fault.
> 0x00007ffff7bb35ea in QSqlDatabase::close() () from
> /home/mark/opt/qt501/lib/libQt5Sql.so.5 (gdb) bt
> #0  0x00007ffff7bb35ea in QSqlDatabase::close() () from
> /home/mark/opt/qt501/lib/libQt5Sql.so.5 #1  0x00007ffff7bb475d in
> QSqlDatabase::~QSqlDatabase() ()
> from /home/mark/opt/qt501/lib/libQt5Sql.so.5 #2  0x00007ffff7bb723d in ??
> () from /home/mark/opt/qt501/lib/libQt5Sql.so.5 #3  0x00007ffff73faa2d 
> in QHashData::free_helper(void (*)(QHashData::Node*)) () from
> /home/mark/opt/qt501/lib/libQt5Core.so.5 #4  0x00007ffff7bb6e1c in ??
> () from /home/mark/opt/qt501/lib/libQt5Sql.so.5 #5  0x00007ffff664c612 
> in ?? () from /lib/libc.so.6 #6  0x00007ffff664c665 in exit () from 
> /lib/libc.so.6 #7
> 0x00007ffff6634c94 in __libc_start_main () from /lib/libc.so.6 #8
> 0x0000000000404569 in _start ()
> 
> There's no mention of my own code.
> 
> I have a Database class which creates database connections using 
> QSqlDatabase::addDatabase(). I create a fresh m_cname (connection 
> name) for each addDatabase() and store it for use in the methods and 
> in the
> destructor:
> 
> void Database::~Database()
> {
>     if (QSqlDatabase::contains(m_cname)) {
>         {
>             QSqlDatabase db = QSqlDatabase::database(m_cname);
>             db.close();
>         }
>         QSqlDatabase::removeDatabase(m_cname);
>     }
> }
> 
> Any suggestions as to what I'm doing wrong?
> 
> Thanks!
> 
> --
> Mark Summerfield, Qtrac Ltd, www.qtrac.eu
>     C++, Python, Qt, PyQt - training and consultancy
>         "Programming in Go" - ISBN 0321774639
>             http://www.qtrac.eu/gobook.html 
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