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Questions tagged [gdb]

The tag has no usage guidance.

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Find applications accessing certain memory address / trace memory access

Is there some way on Linux or Unix systems to determine if a distinct physical or virtual memory address has been accessed? I know the address or list of addresses but want to know if and what ...
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0answers
14 views

SIGSEGV on dlopen with gdb

I'm currently building a shared library. The goal is to inject this lib in a process. Unfortunaly when I inject this lib in the process I get a SIGESGV about ostream. Here is a MWE to reproduce the ...
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1answer
23 views

Get backtrace from core dump using gdb via shell script(non interactive)

I have core dump file and gdb. I can do gdb <executable> <core_file> (gdb)bt This will give me backtrace but I want to do this using a shell script and in non-interactive mode. ...
1
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1answer
72 views

How to enable TUI for gdb on Debian 9?

When debugging it is often helpful to loot at assembly, but on Debian 9 when I try layout asm I get: Undefined command: "layout". Try "help". According to some internet research it seems like I ...
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0answers
36 views

Debugging android kernel goldifish emulator under Mac OS Mojave

I need to debug android kernel goldfish under MacOS Mojave. So i cloned android-goldfish-3.18 and android-aosp-9.0.0_r22. I built aosp under macos while the kernel under debian. Obviously I built ...
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0answers
47 views

Qemu-user : get memory maps while debugging remotely

I am trying to get the memory map of a process I am debugging remotely (peda pull request link), the process is ran with qemu-user, for example: qemu-arm -L /usr/arm-linux-gnueabihf/ -g 1234 ./ch47 ...
0
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3answers
20 views

gdb-customize command, how to test whether a variable is set?

I'm debuging with gdb and need to define some helper commands. Basically I want my customized command to operate differently depending on the number of args given. So I have to test whether $arg* is ...
5
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2answers
358 views

Safest way to force close a file descriptor

Sometimes you need to unmount a filesystem or detach a loop device but it is busy because of open file descriptors, perhaps because of a smb server process. To force the unmount, you can kill the ...
0
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1answer
51 views

tracking segfault upon invocation of perl script (mytop tool and similar)

on my gentoo machine, mytop 1.9.1 quits upon invocation with the following output: # mytop Useless use of private variable in void context at /usr/bin/mytop line 1001. "my" variable $data masks ...
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0answers
10 views

Thread scheduling behavior between steps of GDB compared to non-stepped execution

The GDB manual states that when using all-stop mode for debugging a multithreaded application, it is not possible to advance every thread in lock-step by exactly one statement. This makes sense since ...
4
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1answer
115 views

How to prevent a process from writing to the systemd journal?

I am using a third party .NET Core application (a binary distribution used by a VS Code extension) that unfortunately has diagnostic logging enabled with no apparent way to disable it (I did already ...
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2answers
63 views

How to build the GDB documentation from source?

I've downloaded the GDB source: git clone git://sourceware.org/git/binutils-gdb.git now how do I generate the documentation from source as can be downloaded from: https://sourceware.org/gdb/current/...
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2answers
3k views

What does C@t{++} mean in the gdb man page?

I was reading the manpage for gdb and I came across the line: You can use GDB to debug programs written in C, C@t{++}, Fortran and Modula-2. The C@t{++} looks like a regex but I can't seem to decode ...
4
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1answer
177 views

Why some libraries and other parts get repeated in the linux virtual memory with gdb?

This is the result of looking at virtual memory of a process in gdb; I have some questions regarding this: Why are some parts of the virtual memory are repeated? For example, our program (stack6) and ...
5
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1answer
351 views

How to produce a VLC stack trace?

I've reported a VLC bug and included the output of gdb's bt full, but the response from a project representative is that the trace is "incomplete". How can I produce a trace that would be usable to a ...
3
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2answers
3k views

gdb in one command

When I debug an executable program with arguments arg1 arg2 with gdb I perform the following sequence gdb file ./program run arg1 arg2 bt quit How can I do the same from one command line in shell ...
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0answers
346 views

Given a core-dump, how to get the files opened by the late process?

Answers to related questions all suggest using lsof or checking under /proc/NPID/, which is not helpful for when the process is already gone and only its core-dump remains. However, it should be ...
0
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0answers
286 views

pstack outputs nothing. What does it mean?

Most of the time, pstack prints the stack nicely. Once in a while, I run pstack 1234 against a process 1234, and it outputs NOTHING. I can run it again, and again it outputs nothing. Once it goes ...
0
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1answer
180 views

Why does pstack launch gdb (and how to prevent it)?

Running pstack on a process sometimes causes gdb to attach to that process on one of my Linux servers. Why would pstack launch gdb, and how can I prevent that? Details: gdb is running as: /user/bin/...
1
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1answer
249 views

How to trace line by line by “gdb” C/C++ code? [closed]

I have installed gdb and added -g option to my compilation command, but when I try (gdb) s or (gdb) n it says: The program is not being run. It only works when I try (gdb) r and goes and stops ...
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1answer
54 views

Powerline and gdb

GDB in TUI-Mode shows strange behaviour. I'm using powerline and it seems that the font is the wrong one. Exist there a solution to have a pretty command line? How can I invoke a program not using ...
0
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1answer
66 views

Install new development tools on old system

I run 32 bit Centos 6.9 Linux with installed development tools for it with command: yum groupinstall 'Development Tools' But it installs very old GCC and GDB. What is the best way to install newer ...
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0answers
510 views

Building newer GDB failed due C++11

I run 32 bit Centos Linux with gdb ver 7.2 on it. I need to update GDB. I got errors below while building GDB 8.1: checking whether g++ supports C++11 features by default... no checking whether g++ ...
1
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1answer
1k views

GDB command to print the address of starting of buffer (stack)

For gdb debugger (gdb) p &buffer This command is used to print the content of starting of buffer (stack), or print the address? If it is content, how to print the address?
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0answers
119 views

Interrupt a slow gdb command?

I unwisely asked gdb to list all defined functions. (gdb) info function Now it is excitedly slurping up CPU and memory. If I'm really quick about it, GDB will stop with Ctrl-C and give me a prompt ...
6
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3answers
853 views

GDB step in delays

I am making a nice presentation of ARM assembly code execution and I would need GDB to step the code every 1 second infinitely long (well until I press CTRL+C). Has anyone got solution? I don't want ...
2
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2answers
606 views

where does gdb put the log file?

This starts partially from why doesn't gdb like aliases Now I put the following arguments - gdb firefox-esr (gdb) set logging file my-firefox-esr-1802018.log (gdb) set pagination 0 (gdb) show ...
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4answers
1k views

why doesn't gdb like aliases [duplicate]

I made an alias ff and sourced it from ~/.zsh/aliases.zsh. The aliases run well themselves: alias ff ff='firefox --safe-mode' and it runs as expected. But when I try to run it under gdb I get: &...
3
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1answer
230 views

Accessing memory mapped registers in gdb

I'm trying to read (hopefully write as well) to the memory mapped hardware registers in a qemu virtual machine using gdb (remote connected). But it's just not working: (gdb) p *0x2000000 Cannot ...
4
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0answers
277 views

gdb hangs on “quit()”

When I want to close gdb, I frequently mistype quit() instead of quit Whenever that happens, gdb hangs indeterminately, and I end up using kill -9 gdb_pid to terminate it. I would like to ask: ...
2
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0answers
107 views

Is there anyway to verify validity of dlopen handle?

In my case after my program cas dlclose program is crashing and I am not getting stack trace for dlclose or any function on upper frames. I know handle value of dlclose . Is there anyway to check if ...
1
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1answer
727 views

How to quit an application running in gdb gracefully when the application isn't reponding.

This is somewhat related to gdb set overwrite logging on should overwrite gdb.txt correct? . Let's say I'm running a session of some application. For example purposes, let me take the example of ...
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2answers
3k views

Turning off kASLR to debug linux kernel using qemu and gdb

I'm trying to debug linux kernel using qemu and gdb. The problem is that gdb won't stop at breakpoint. I've searched about it and found that turning kASLR off may help, because kASLR confuses gdb. ...
1
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1answer
408 views

How do I find detached debug symbols for decompilation?

I am trying to debug a segfault without code a binary in a nonstandard path (specifically in /frs/alg/alg/bin/) and I was noticing that the decompiled code has fewer symbols than when debugging under ...
3
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1answer
202 views

gdb set overwrite logging on should overwrite gdb.txt correct?

I was looking at Logging Output and had been trying this particular command - set logging overwrite on AFAI understood it, that command is supposed to overwrite the contents of gdb.txt but it does ...
0
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1answer
310 views

Quit program run by GDB when terminate screen

I am running my program using screen and GDB. How I run my program: screen -dmS adapter "./run-adapter.sh" In run-adapter.sh gdb -ex "handle SIGPIPE nostop noprint pass" -ex run -args ./Adapter ...
4
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1answer
1k views

Hardware breakpoint in GDB +QEMU missing start_kernel

I am trying to debug a kernel running on QEMU with GDB. The kernel has been compiled with these options: CONFIG_DEBUG_INFO=y CONFIG_GDB_SCRIPTS=y I launch the kernel in qemu with the following ...
1
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1answer
40 views

Switching between shared buffers in emacs gdb mode without mouse (in text-terminal)

From the documentation link here: https://www.gnu.org/software/emacs/manual/html_node/emacs/Other-GDB-Buffers.html When gdb-many-windows is non-nil, the locals buffer shares its window with the ...
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3answers
5k views

Why does GDB need the executable as well as the core dump?

I'm debugging using core dumps, and note that gdb needs you to supply the executable as well as the core dump. Why is this? If the core dump contains all the memory that the process uses, isn't the ...
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0answers
61 views

Redirect the output to an already running program

I have a program running on terminal 1 and waiting for input from stdin. I programmed this program so it is vulnerable to buffer-overflow. I want to change it's flow to function2() within the program ...
0
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1answer
69 views

is there a way to know if signals are present in your application and which signals are there? [closed]

Please see what does `handle SIG33 pass nostop noprint` does when used in gdb . I am guessing from the answer shared by Stephen Kitt, that info. about signals is in the source code somewhere. If I ...
0
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1answer
668 views

what does `handle SIG33 pass nostop noprint` does when used in gdb

In gdb, the usual instructions for debugging given are - gdb $package set logging on set pagination 0 handle SIG33 pass nostop noprint run and of course than collecting backtraces and all. Of ...
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2answers
329 views

Can GDB decode core if it were piped?

I have huge core files, and hence set the core_pattern is set to gzip as they are written. Later if the backtrace is to be obtained, first gunzip has to be done (and it takes a very long time!) ...
3
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1answer
2k views

ptrace: Operation not permitted when attaching to a zombie process

I have a reproducible situation where a compiler instance goes into a zombie state when I rebuild a package, but gdb won't permit me to attach: serenity ~ # ps ax | grep defunct 11351 pts/1 Z+ ...
2
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1answer
2k views

gdb doesn't step into function although source is available

I have a shared library compiled with -g -O0 including: void MyClass::whatever() { ... doSomething(myImage, myPoints); ... } bool MyClass::doSomething(const Image& image, std::vector<cv:...
2
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1answer
762 views

Debug a setuid binary as non-root

I have a CentOS 7 system. I need to attach my GDB to an already running application, but get the (apparently usual) "ptrace: Operation not permitted." error. Running GDB as root prevents the error, ...
0
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1answer
246 views

guile2.0 conflicts guile?

I'm trying to install gdb which requires guile2.0 as dependency. However guile ver.2.0.11-3 is already installed, as a dependency of make. Now when pacman tries to install guile2.0, installation ...
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1answer
117 views

Transferring control of ptrace to another process

I asked this question in the reverse engineering stackexchange: https://reverseengineering.stackexchange.com/questions/15169/transferring-control-of-ptrace-to-another-process because I thought a ...
3
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1answer
1k views

Measure exact clock cycles for a C/assembly program

I need to measure the exact number of clock cycles it takes to execute a program. I already used the clock() function but it's values are dependent on system parameters. I could not figure out how to ...
7
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1answer
3k views

What exactly is and what does a core dump of process contain?

It's clear that GDB can generate a core dump of process for example via its wrapper - gcore, however it's not clear what exactly it includes and it's really hard to find an answear because different ...