Debugging with Core Dumps

One of my binary crashed. And the bt is pointing to (static) library part
I tried compiling library with debug sumbols enabled. But the bt is pointing to wrong code
How to debug this scenario ?

Professional grade explanation, much appreciated.

Bro I watched this video some time ago and forgot to reset my core dump limit, and I just saw 3 GB of brave core dump.

There isn’t a better video than this in the world!!

My problem under Ubuntu - no core dumped generated. I tried everything already..

thanks for sharing the knowledge, btw we are using the same slack notify sound. lol

i didn't find core file after dump

In windows you can also do this with DebugDiag (and its analyzer). It can even directly analyze crashed .NET processes if you want 😊

You didn't explain how to compile the program to contain all the debugging information so that the core file could be debugged in situ on a remote system where the source code to step through would not be available, for example at a client's site.

Thanks. I enjoyed your video. I'm trying to run RLCraft (a modpack for Minecraft) and have fairly rudimentary coding skills and knowledge. Anyway, the crash report that I got when I loaded the launcher said, "Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again." So that's how I found your video. I still don't know what to do to fix the issue but I do now understand what it's talking about. Thanks

Can I unlimit -c for certain processes, but not for all?

Thankyou for helping the ‘C’ community

nice

thanks matthew

Great video

IAs someone who writes code for embedded systems and uses mainly python for tasks on my PC, this was really interesting, because I didn't ever do a core dump - I mean, normally I don't even have a file system 😅

sad little zero made my day

"core" file is not being generated in my linux. I went through all the same commands, as it is explained in the video

great video! thank u

Nice video! But of the most helpful things with core dumps is the ability to walk the call stack in gdb.

Are coredumps available in python?

i have core dump file how can i analyze it and which tool i need to download

kill -SEGV 4787
"Oops, wrong pro..." universe explodes

There's hope...

"You could fill up your disk pretty quick, especially with how frequently your code crashes."

ROASTED

Feeling sad for the one who was flying 🥲

keep in mind that sending core dumps may have privacy implications. For example, if Excel or Word crash and send a full core dump to microsoft, it would be sending the document the user was viewing/editing as a side effect (since it is loaded on memory), it is also true for any program data manipulate user files/data.

I have some problem in usage of GDB. can you please help me out here?

So... If I set the limit to a finite number and the core dump gets truncated... how useful is it gonna be than? Can I be sure to at least have the stack in it then?

Poor Lego guy :(

"Now, when this program eventually crashes, as we knew it would, it says that it 'Core dumped'. It means the computer dumped the content of the process' memory when it crashed. Except for the fact that it really didn't. I'm sorry to break it to you, but sometimes computers lie." - Jacob the Sorber, 1984, University of Wakanda

very Informative, Thanks for the video!

@Jacob Sorber... one of the best video on core dump analysis ...Thanks Jacob

How to write our own memory leak detector?

rand()%255 should have been rand()&255 or rand()%256 :)

@Dreywill on telegram is a real vendor I can’t believe my eyes that man too real goat on this he on telegram he sell credit card with high balance

Wait, that means the user finding bug will need to tinker with the machine (assuming can get admin privileges) then try to crash it again to actually get a core dump. Sounds like too many loops to jump to help the developer to fix the app. Then how those apps with crash reports can get it without that?

How to deal with coredumps that are generated/dumped in the target which is running on a different architecture?

Assume,
-> Host is x86 and Target is armhf
-> Target doesn't have gdb/memory to debug on Target itself.

my school won't let me use ulimit -c to anything other than 0 on their machines. So I just used git and used it on my local machine. Hope that helps anyone.

lol, that was an overly dramatic intro.

Oh boy, core files are certainly big. I have a small program that generates a 71MB core file.

Are you sitting on the floor or some small chair? I am looking for ergonomic sitting positions as debugging can take hours or days.

Nice. But maybe using a safe langage like OCaml that doesnt segfault could solve the same problem :p

Hi Jacob , this was a great video but I still have a question. When you deploy your code you are usually using release build which is optimized and probably won't have the debug symbols and further more the target might not have a lot of memory. So how can we use this core dump in such scenario?

My linux system has core dumps to unlimited by default.
I'm using Arch

For a detailed discussion, you could have talked about the "??" problem when debugging with coredump files.

A good introductory video, but a bad waste of 1 minute at the start. Cheers!

This was very helpful. Thank you!

great, but an issue, i have a mac, running vscode on its terminal, when i tried gdb but it says "bash gdb command not found"