Question

我正在Python 3.5编写一个程序，并使用PyQt4来执行所有GUI功能。当我运行程序时，有时会出现分段错误。我在网上查找了解决方案，找到了使用gdb的{{3}}。

我尝试以这种方式运行我的程序，但不知道如何读取输出。有人可以给我一个提示吗？

输出：

gdb python3
GNU gdb (Ubuntu 7.11.1-0ubuntu1~16.5) 7.11.1
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
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and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
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<http://www.gnu.org/software/gdb/bugs/>.
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<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
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Reading symbols from python3...(no debugging symbols found)...done.
(gdb) run GUI3.py 
Starting program: /usr/bin/python3 GUI3.py
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7ffff3ad0700 (LWP 26031)]
[New Thread 0x7ffff12cf700 (LWP 26032)]
[New Thread 0x7fffeeace700 (LWP 26033)]
[New Thread 0x7fffd3da2700 (LWP 26034)]
[New Thread 0x7fffd2042700 (LWP 26035)]
[New Thread 0x7fffd1841700 (LWP 26036)]
[New Thread 0x7fffd1040700 (LWP 26037)]
[New Thread 0x7fffbb952700 (LWP 26038)]
Run function needs to be implemented

Thread 1 "python3" received signal SIGSEGV, Segmentation fault.
QWidgetBackingStore::sync (this=0x1ec5d30) at painting/qbackingstore.cpp:1239
1239    painting/qbackingstore.cpp: No such file or directory.
(gdb) backtrace 
#0  QWidgetBackingStore::sync (this=0x1ec5d30) at painting/qbackingstore.cpp:1239
#1  0x00007fffe0e11c50 in QWidgetPrivate::syncBackingStore (this=0x1907c20)
at kernel/qwidget.cpp:1894
#2  0x00007fffe0e249b8 in QWidget::event (this=this@entry=0x1b3b380, event=event@entry=0x20bab70)
at kernel/qwidget.cpp:8693
#3  0x00007fffe12089b3 in QMainWindow::event (this=0x1b3b380, event=0x20bab70)
at widgets/qmainwindow.cpp:1478
#4  0x00007fffe1cfc28b in ?? ()
   from /usr/lib/python3/dist-packages/PyQt4/QtGui.cpython-35m-x86_64-linux-gnu.so
#5  0x00007fffe0dcdfdc in QApplicationPrivate::notify_helper (this=this@entry=0x18f9d70, 
receiver=receiver@entry=0x1b3b380, e=e@entry=0x20bab70) at kernel/qapplication.cpp:4570
#6  0x00007fffe0dd4f16 in QApplication::notify (this=0x17de970, receiver=0x1b3b380, e=0x20bab70)
at kernel/qapplication.cpp:4356
#7  0x00007fffe1ebc0c6 in ?? ()
   from /usr/lib/python3/dist-packages/PyQt4/QtGui.cpython-35m-x86_64-linux-gnu.so
#8  0x00007fffe2eb390d in QCoreApplication::notifyInternal (this=0x17de970, 
receiver=receiver@entry=0x1b3b380, event=event@entry=0x20bab70)
at kernel/qcoreapplication.cpp:955
#9  0x00007fffe2eb73c6 in QCoreApplication::sendEvent (event=0x20bab70, receiver=0x1b3b380)
at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#10 QCoreApplicationPrivate::sendPostedEvents (receiver=receiver@entry=0x0, 
event_type=event_type@entry=0, data=0x18fc490) at kernel/qcoreapplication.cpp:1579
#11 0x00007fffe2eb76a3 in QCoreApplication::sendPostedEvents (receiver=receiver@entry=0x0, 
event_type=event_type@entry=0) at kernel/qcoreapplication.cpp:1472
#12 0x00007fffe2ee413e in QCoreApplication::sendPostedEvents ()
at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:236
#13 postEventSourceDispatch (s=0x1900aa0) at kernel/qeventdispatcher_glib.cpp:300
#14 0x00007fffe2a62197 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#15 0x00007fffe2a623f0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#16 0x00007fffe2a6249c in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#17 0x00007fffe2ee42ae in QEventDispatcherGlib::processEvents (this=0x17be390, flags=...)
at kernel/qeventdispatcher_glib.cpp:450
#18 0x00007fffe0e7b616 in QGuiEventDispatcherGlib::processEvents (this=<optimised out>, flags=...)
at kernel/qguieventdispatcher_glib.cpp:204
#19 0x00007fffe2eb218f in QEventLoop::processEvents (this=this@entry=0x7fffffffd7d0, flags=...)
at kernel/qeventloop.cpp:149
#20 0x00007fffe2eb24f5 in QEventLoop::exec (this=this@entry=0x7fffffffd7d0, flags=...)
at kernel/qeventloop.cpp:204
#21 0x00007fffe2eb84b9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1227
#22 0x00007fffe1e6aa2b in ?? ()
    from /usr/lib/python3/dist-packages/PyQt4/QtGui.cpython-35m-x86_64-linux-gnu.so
#23 0x00000000004e9b7f in PyCFunction_Call ()
#24 0x00000000005372f4 in PyEval_EvalFrameEx ()
#25 0x0000000000540199 in ?? ()
#26 0x0000000000540e4f in PyEval_EvalCode ()
#27 0x000000000060c272 in ?? ()
#28 0x000000000060e71a in PyRun_FileExFlags ()
#29 0x000000000060ef0c in PyRun_SimpleFileExFlags ()
#30 0x000000000063fb26 in Py_Main ()
#31 0x00000000004cfeb1 in main ()
(gdb)

Answer 1

嗯，提示：您所看到的是调用堆栈。

你肯定知道自己是程序员，调用函数（或方法）需要将调用的上下文（参数，局部变量，返回地址）添加到内存中称为堆栈的区域。

因此，当您发生细分错误时，您会看到您的代码（以及不属于您的代码）所做的调用以及尚未返回的调用。由于您的流程遇到了段错误，它没有继续执行或“放松”＃34;堆栈 - 它只是倾倒了所有的帧。（并注意框架从最深到最浅列出。）

幸运的是，大多数堆栈帧都具有正在运行的函数的名称，因此您可以更好地确定在有问题的段中您访问内存的确切位置。不幸的是，堆栈跟踪似乎没有行号（这些都是?? s的所有对），因此除了对函数的调用之外，你无法精确定位它。构成下一个堆栈框架。也不幸的是 - 看起来大多数/所有这些名称都是PyQT或QT或Python的内置函数，而不是你自己的函数（尽管我可能在这里错了，尤其是如果你已经超负荷了 - 这也使得你更难以弄清楚你导致这些段错误的位置 - 因为你可能设置了一些值，以后的情况下会出现这样的代码：＆＃39;不是你的无效访问。

Answer 2

有人可以给我一个提示吗？

当你在第三方代码中看到像libQtGui.so崩溃时，在这种情况下，有必要谷歌堆栈跟踪的顶部部分，希望找到相关的已报告错误，你可以找到更新的变通方法或版本号到。

在这种情况下，Google搜索QWidgetPrivate::syncBackingStore导致此错误https://bugreports.qt.io/browse/QTBUG-41428与另一个错误https://bugreports.qt.io/browse/QTBUG-41108重复。虽然它是针对Mac OS报告的，但它也可能与x86_64-linux-gnu相关。

如何读取gdb输出

2 个答案: