He/Stack Trace
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מה זה עקבות־מחסנית (Stack Trace)?
פעולת עקוב־מחסנית מייצרת פלט שמספק מידע על תתי־תכנית ושרשרת קריאות לפונקציות של התכנית העקרית עד לנקודה מסויימת בתכנית. רוב השימוש בעקוב־מחסנית נועד לניפוי תקלים מסוג מסויים. עקוב־מחסנית אמור לסייע לצוות הפתוח והתמיכה בהבנת הבעיה אחריה הופעל המעקב, או כיצד פועלות תתי־מערכות שונות יחד במהלך ביצוע תוכנית מסויימת. להלן דוגמת פלט עקבות־ערמה שהופעל במערכת הפעלה מק OX; מערכות הפעלה שונות מן הסתם יציגו מידע באופן שונה במקצת:
Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Application Specific Information: abort() called Thread 0 Crashed:: Dispatch queue: com.apple.main-thread 0 libsystem_kernel.dylib 0x9769169a __pthread_kill + 10 1 libsystem_pthread.dylib 0x9836bf19 pthread_kill + 101 2 libsystem_c.dylib 0x9bde5eee abort + 156 3 libglib-2.0.0.dylib 0x02b5dd8a g_assertion_message + 346 4 libglib-2.0.0.dylib 0x02b5e470 g_assertion_message_expr + 96 5 libgncmod-gnome-utils.dylib 0x0029ec4a gnc_main_window_init + 2650 6 libgobject-2.0.0.dylib 0x02ae7496 g_type_create_instance + 470 7 libgobject-2.0.0.dylib 0x02ad51a2 g_object_new_internal + 562 8 libgobject-2.0.0.dylib 0x02ad5a90 g_object_newv + 480 9 libgobject-2.0.0.dylib 0x02ad5b7d g_object_new + 61 10 libgncmod-gnome-utils.dylib 0x002a03d7 gnc_main_window_new + 39 11 libgncmod-gnome-utils.dylib 0x0029a6f5 gnc_gui_init + 581 12 Gnucash-bin 0x00011387 main + 1143 13 Gnucash-bin 0x00010ed6 start + 54
פלט זה מראה מדוע גנוקאש קרסה (משתנה בלתי תלוי בפונקציית init של החלון הראשי, כשל); ללא פעולת עקבות־מחסנית, משימת אבחן קריסה יכולה להיות משימה קשה ומורכבת ביותר. לפני שיגשו לטפל בסוגיות, מפתחים יבקשו בדרך כלל גם את ה־קובץ עקיבה, שלרוב יספק מידע שימושי נוסף. במקרה מעלה, נמצא את הודעת המשתנה בלתי תלוי בפועל שיסביר את נטישת התכנית (הקריסה).
עדיף עם סמלי איתור תקלים
ניתן ללהפיק עקבות־מחסנית ברמות מילוליות משתנה. כברירת מחדל, רוב ההפצות יאפשרו רק עקבות־מחסנית 'גסה' מאוד, בה לא יוצג מידע רב על כל פונקציה בנפרד. מעקב־המחסנית יהיה שימושי הרבה יותר אם סמלי ניפוי תקלים זמינים. נא לנסות לאפשר אותם, ככל שהדבר מתאפשר. במידה ומריצים את גנוקאש:
- , את חבילתמחבילת תכנה מוכנה בלינוקס, נא לחפש באנצעות מנהל ההתקנה -dbgאו
- במידה ונעשב שימוש גם בחבילות נוספות כדוגמת AqBanking, נסו למצוא ולהתקין את חבילת -dbg שלהן גם כן. לאחר שהסוגיה טופלה, ניתן להסיר את החבילות הללו.
Optional Preparation of Scheme Code
- ToDo
- perhaps somewhere else is a better place for this sction.
If reports are affected, see The Guile Reference Manual: Programmatic Error Handling
How to obtain a Stack Trace
macOS
Every time an application crashes in Mac OS X, the system writes a crash report with a stack trace to $HOME/Library/Logs/DiagnosticReports or $HOME/Library/Logs/CrashReporter, or both, depending on what version of OS X you're running. The crash reports are easily viewed with Applications:Utilities:Console, and if you're reporting a crash in Bugzilla or to the user's list you should attach one to your report.
About Debuggers
In order to get a stack trace on Linux or Windows one must have either the GNU Debugger, gdb, or the LLVM Debugger, lldb, installed.
- Linux users should their package manager to install one or the other if necessary.
- Window users can download them at
- Fixme: gdb: Mingw
- http://releases.llvm.org/download.html
Gdb is a bit simpler to use, so the instructions below are for gdb.
Linux
Additionally, if you're using packages supplied through a linux distribution (you did not compile GnuCash yourself) you probably also need to install a debug symbol package (see below).
Once you have installed a debugger (and symbols as needed), there are two ways to put GnuCash under the debugger's control. Starting GnuCash under the debugger is a bit more straightforward, but the debugger slows down the program quite a bit. So it might work better for you to start GnuCash as usual, get to the point where some action provokes the crash, then attach the debugger to the running GnuCash.
Starting GnuCash under gdb
- run gdb gnucash
- at the gdb prompt, type: "run". If you need to pass command line arguments, add them here, e.g. "run --nofile"
- Example
$ gdb gnucash
GNU gdb (GDB; openSUSE Tumbleweed) 8.3.1
Copyright (C) 2019 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "x86_64-suse-linux".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://bugs.opensuse.org/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from gnucash...
(gdb) run --nofile
Attach gdb to running process
- Start gnucash normally.
- In a terminal window run ps afx (some people prefer ps aux) to find out the process number (PID) of the running gnucash process; it might be called "gnucash" or "gnucash-bin". Say the PID is 12345.
- Run gdb gnucash
- Attach to the running process by typing attach 12345; gdb will temporarily stop the program
- Continue program execution by typing c at the "(gdb)" prompt
Obtain the stack trace
- Provoke the crash. When GnuCash crashes gdb will print the reason for the crash and present the "(gdb)" prompt again.
- Type bt (bt full might provide additional info about local variables).
- Gdb will print the backtrace.
Exit Gdb
ctrl-d or quit will end the gdb session.
Please copy and paste the error and stack trace from the terminal into a bug report; see Bugzilla for details about creating a new one if you haven't already.
Windows
On Windows gdb has to be installed before you can generate a stack trace. While we provide some details below on how to do all of that we recognize this may be too challenging for the average user. If you have been asked to provide a stack trace, but you are using GnuCash on Windows only and find these instructions too daunting, please respond along the lines of
- "I'm sorry, but I encountered this problem only on Windows and I am not familiar enough with gdb on Windows to obtain stack traces there"
That's a fair answer even though in many cases your bugreport can only be worked on if you or someone else can actually produce such a stack trace.
- Install "gdb" from mingw.org [1]
- Open a Windows command prompt and type:
set PATH=C:\Program Files\gdb\bin;%PATH% gdb "C:\Program Files\gnucash\bin\gnucash"
- Be careful to use the actual paths in which you have installed gdb and gnucash respectively.
- #Obtain the stack trace with the instructions above.
You can provide even better stack traces if you tell gdb where in memory dynamically loaded modules got mapped to, because otherwise function calls into those are only written as '??'. See here and here for a way to do this.
To enter [ and ], use set editing off.
See also
Other explanations on how to obtain stack traces:
- http://live.gnome.org/GettingTraces
- http://www.dirac.org/linux/gdb/06-Debugging_A_Running_Process.php
- (in German) http://www.linuxwiki.de/gdb
Debug symbol information
Gnucash needs to be compiled in a way that has the debug symbols still included in the resulting binary libraries.
- When compiling gnucash yourself, this is achieved by using the configure option ./configure --enable-debug.
- Distributions usually offer them in a separate packages appending -dbg or -debug.
Gentoo
When emerging gnucash on gentoo, you need to make sure that
- the "debug" USE flag is enabled
- and "FEATURES=nostrip" is set to disable symbol stripping.
Ubuntu / Debian
On Ubuntu, the debug symbols are available in a separate package called gnucash-dbg. See https://wiki.ubuntu.com/DebuggingProgramCrash
This issue is also explained here https://wiki.ubuntu.com/Backtrace.
| Tracefile | Logging | Bugzilla#Using Bugzilla | FAQ#Q: How do I run GnuCash under gdb and get a stack trace? |
