When linking, multiple common symbols may appear with the same name. "B" "b" The symbol is in the uninitialized data section (known as BSS ). "A" The symbol's value is absolute, and will not be changed by further linking. If lowercase, the symbol is local if uppercase, the symbol is global (external). Where letters can be empty for all symbols or a combination: Reporting it to the Arch bugtracker would not help and might even be counterproductive because it tends to waste time of the bug wranglers.Usage: python linsymbtobch.py symbol_file.txt output_bochs_syms.txt. Arch Linux can not magically fix upstream bugs. If the bug is not related to Arch Linux and is reproducible anywhere else, only report it to upstream. See Bug reporting guidelines#Upstream or Arch? for more information. Inspect the PKGBUILD of the package, which is possible with the Arch build system, to see how it gets packaged. This also includes issues with libraries or dependencies (e.g if one of them is not built with a specific feature that is needed). If the bug is introduced due to how Arch Linux packages this application, report it to. If you are proficient with Python, you can try to fix this and include the fix in the bug report.įirst check if the bug in question is a packaging bug. Prefix the command with gdb -args if the executable in question needs arguments as well.įor pure shell scripts, you can also use bash -x script_name or bash -xv script_name.įor Python applications, the output will often say which file and line number the crash occurred at. ![]() You can then temporarily put "gdb" right in the shellscript, before the name of the executable, for debugging purposes. If it is a shell script, open up the shell script in a text editor and see (usually at the bottom of the file) if you can find the name of the real application (ELF file). If it says Python script, you know you are dealing with an application written in Python. If it says ELF, it is a binary executable and is usually written in C or C++. Use file on the executable to get more information: If it is not written in C or C++, but perhaps in Python Make sure the interpreter in question (like /lib/ld-linux-x86-64.so.2) actually exists. (replace /usr/bin/ appname with the location of your executable) $ readelf -a /usr/bin/ appname | grep interp If you get no such file or directory when running an application, try the following command: $ LD_DEBUG=files appname > appname.log 2>&1 Setting LD_DEBUG=files gives another overview of what files an application is looking for. Tip: If you wish to grep the output from strace, you can try: strace -o /dev/stdout appname | grep string. If an application tries to open a file that is not there, it can be discovered by strace.įor finding which files a program named appname tries to open: Strace finds out in detail what an application is actually doing. If a program hangs, this makes it easier to pinpoint the location of the error. Consider -v and -leak-check=full to get even more info.Īnd run the output through kcachegrind to graphically explore the functions the program uses. It will provide a lot of helpful debug output if there is a crash. valgrind is a tool that emulates a CPU and usually shows where things go wrong or provide info in addition to gdb. If you have a "core" file, it can be used together with gdb to get a backtrace:Īssuming you have an unstripped binary without inlined functions, it is usually a good idea to also run that program through valgrind. Afterwards, post the trace to a pastebin service and include the URL in your bug report. While running from gdb, you might have to wait for the segfault. See Debugging/Getting traces#Getting the trace for more instructions how to use it to obtain a trace. Gdb is an ancient and well tested application for debugging applications. There are several techniques that can be used to figure out what went wrong. See core dump to find whether generation of core dump files is enabled on your system and where do they go. The location of core dumps may vary depending on the operating system configuration. If the application is compiled in a debug-friendly way, the "core" file can be used to find out where things went wrong. Even though the word "debug" is used, it is not intended as a guide for how to debug programs while developing.Ī core dump is a file containing a process's address space (memory) when the process terminates unexpectedly. ![]() This page is mainly about how to gather more information in connection with bug reports. Reason: This article might as well be about debugging in general, so that other useful tools like ltrace can be added here.
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