If I start gdb -tui or gdbtui with an -g flag compiled file, then set b main and press r I get the hint dl-debug.c:74 no such file or directory and the output while stepping through the source window will be written to the source window at the bottom, which also messes up this window so that is not really readable. I've already looked at askubuntu.com and Sourceware Bugzilla – Bug List and at this site but found no solution.
I also tried out sudo apt-get install ddd on another machine to go to the trouble out of the way, but then I only get authentication failure, which I also already asked without response on ask ubuntu.
Any help or hint is appreciated.
dl-debug.c:74 no such file or directory
This message means that you've tried to step into GLIBC (more precisely the dynamic loader) source, which you didn't install.
Solution: don't try to step into it, or install GLIBC source and make GDB find it (help directory).
Related
I recently went to try to debug a program with GDB and got the following error:
gdb: error while loading shared libraries: libncursesw.so.6: cannot open shared object file: No such file or directory
So I went investigating and tried the obvious things, ie sudo apt-get install libncursesw5 (and dev variants) and apt reports that I've already got the latest version...so next I tried reinstalling GDB, problem persists. The output of ldd with GDB confirms to me that it still doesn't know where this mythical libncursesw.so.6 file is, so I go digging around in the usr/lib/x86_64-linux-gnu folder and run ls libncu* which returns six results: libncurses.a, libncurses++.a, libncurses.so, libncurses++w.a, libncursesw.a, and libncursesw.so...but no libncursesw.so.6. I then naively attempted to just make a copy of libncursesw.so named libncursesw.so.6, to which gdb reports that this file is "too short".
In googling I can't seem to find a good explanation on how to get this file in place? Every other answer I see just suggests running sudo apt-get install libncursesw5 (or something similar) but I've already tried pretty much every variant of that I can think of. I was going to remove it and then reinstall it but when I went to do that it gave me a scary warning that I could be doing something potentially harmful to my system so I aborted that idea.
Some context that also might(?) help:
I'm running a pretty recent install of Linux Mint 19.3 Cinnamon, and this was my first time trying to run GDB on my new computer. I basically set this new computer up as a new install, just porting over my home directory and a couple of the more useful hidden . files from my old laptop...I figure this shouldn't be the reason GDB is failing/these files don't exist on the new machine but just in case I'm mentioning it.
obvious things, ie sudo apt-get install libncursesw5
You want libncursesw6, not libncursesw5.
I have an OCaml program that worked fine on Ubuntu 16 but when recompiled and run on Ubuntu 20 I get the following error:-
$ ocamldebug ./linearizer
OCaml Debugger version 4.08.1
(ocd) r
Loading program... done.
Time: 89534
Program end.
Uncaught exception: Sys_error "Illegal seek"
(ocd) b
Time: 89533 - pc: 624888 - module Netaccel_link
No source file for Netaccel_link.
I thought this was due to missing dev libraries but:-
$ sudo apt install libocamlnet-ocaml-dev
Reading package lists... Done
Building dependency tree
Reading state information... Done
libocamlnet-ocaml-dev is already the newest version (4.1.6-1build6).
0 upgraded, 0 newly installed, 0 to remove and 20 not upgraded.
What setup step am I missing on Ubuntu 20?
This looks like a regression bug in libocamlnet and you should report an issue there or, I am a bit pessimistic that you will get any response, you can try to debug the issue yourself.
The problem that you are facing has nothing to do with missing libraries (they will be reported during installation or, if the package is broken, end up in linker errors). It may result, however, from some misconfiguration of the system. If that is true, then you're lucky as you can fix it yourself.
I will give you some advice that might help you in debugging this issue. For more, please try using discuss.ocaml.org as a more suitable media (SO doesn't favor this kind of a discussion and we might get deleted by admins).
The illegal seek exception is thrown when the seek operation is applied on a non-regular file, aka ESPIPE Unix error. So check your inputs. It could be that what was previously regarded as a file in Ubuntu is now a pipe or a socket.
Try to use ltrace or strace to pinpoint the culprit e.g.,
ltrace ./linearizer
or, if it overwhelms you, try strace
strace ./linearizer
Instead of using ocamldebug you can use plain gdb. You can use gdb's interfaces to provide the path to the source code (though most likely it won't work since ocamlnet is not compiled with debug information). I believe that it will give you a more meaningful backtrace.
Instead of using the system installation try using opam. Install your dependencies with opam and try older versions as well as newer versions of the OCaml compiler. Also, try different versions of ocamlnet. Ideally, try to reproduce the environment that used to work for you.
When nothing else works, you can use objdump -d and look at the disassembly of your binary. OCaml is using a pretty readable and intuitive name mangling scheme (<module_name>__<function_name>_<uid>), so you can easily find the source code (search for <module_name>.ml file and look for the <function_name> there)
Finally, just use docker or any other container to run your application. Consider switching from ocamlnet to something more modern and supported.
I am trying to put the gdb to run with eclipse cdt on ubuntu to start debugging some simple programs. So I did the steps I reckon as necessary to get it running:
1. Create an executable project
2. Compile
3. Run
4. Create the file .gdbinit and place it on the main project folder
5. Set some of the debugger configuration:
5. I also tried to find a .gdbinit file that would look some like this:
set schedule-multiple
dir ~/gcc_build/4.7.2/build/gcc
dir ~/gcc_build/4.7.2/gcc
dir ~/gcc_build/4.7.2/gcc/cp
dir ~/gcc_build/4.7.2/gcc/lto
source ~/gcc_build/4.7.2/build/gcc/gdbinit.in
But I didn't find anything similar in my computer, even after doing a:
# find / -name .gdbinit
So, my file .gdbinit end up with the simple content - yes only that:
set new-console on
Then I clicked on Apply and Debug:
The gdb starts working nicely as expected. I press the button "step over / F6" and the debugger goes jumping through the code step by step. Until the point it reaches the command rand() and the gdb hangs with the message:
Can't find a source file at "/build/buildd/eglibc-2.19/stdlib/rand.c"
Locate the file or edit the source lookup path to include its location.
Thus I also tried unsuccessfully to find the rand.c to update this path to include its location:
# find / -name rand.c
# find / -name stdlib
After the error message from GDB complaining that rand.c is missing, then I tried to keep stepping... since then the stepping mode is disable when I restart the debug:
Is this problem happening because some setting for my file .gdbinit is missing? Or some how GDB is not able to find the rand.c from stdlib from c99? When I compile and run the program it runs nicely. Only when I try to launch the debugger is when GDB crashes.
Update: I got the missing rand.c problem after running the commands:
# apt-get install libc6-dbg
# apt-get source libc6
But now a different error appears:
Can't find a source file at "/build/buildd/eglibc-2.19/csu/libc-start.c"
Locate the file or edit the source lookup path to include its location.
Should I also install that library for gdb?
All suggestions are highly appreciated.
From what I saw on your description... looking to the 4th and 5th image you posted, you did right all the required steps.
However, it seems to me that your GDB is attached to several projects. That means that unless you really need that, I would strongly advise you to select all project that you are not currently debugging and delete them from the debugger mode. So, my suggestion is that after you have done all the steps you did so far, then go on:
Debug Configurations > C/C++ Applications: (drop down it)
... then click on each project you are not compiling, with right button from the mouse select "delete" - but don't worry, it will not delete your project, but only the attachment of that project to your debugger mode.
Then restart the eclipse. When you again try to run in the debugger mode, everything will run much smoother than before.
Step1:
Go to https://www.gnu.org/software/libc/ to download glibc.
Step2:
unzip it locally and whenever the eclipse prompts "Can't find ... xxx.c", just load the file into eclipse. It will work.
I'm trying to debug a CUDA program, but when I'm launching gdb like so:
$ gdb -i=mi <program name>
$ r <program arguments>
I'm getting:
/home/wvxvw/Projects/cuda/exercise-1-udacity/cs344/HW2/hw:
error while loading shared libraries: libcudart.so.5.0:
cannot open shared object file: No such file or directory
Process gdb-inferior killed
(formatted for readability)
(I'm running gdb using M-xgdb) If that matters, then CUDA libraries are in the .bashrc
export PATH="/usr/local/cuda/bin:$PATH"
export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/usr/local/cuda/lib64"
error while loading shared libraries: libcudart.so.5.0
This error has nothing to do with GDB: your executable, when run from inside GDB, can't find the library it needs.
export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/usr/local/cuda/lib64"
GDB runs your program in a new $SHELL, so that should have worked. I wonder if there is some interaction with emacs.
In any case, this:
(gdb) set env LD_LIBRARY_PATH /usr/local/cuda/lib64
(gdb) run
should fix this problem.
Update:
as I've mentioned it before, ld path is set properly
No, it isn't. If it was, you wouldn't have the problem.
Now, I don't know why it isn't set properly. If you really want to find out, start by running GDB outside emacs (to exclude possible emacs interactions).
If the problem is still present, gdb show env, shell env, adding echo "Here" to your ~/.basrc, etc. should help you find where things are not working as you expect them.
I've had this problem as well. One way to look at it is that even if the LD_LIBRARY_PATH variable is correct when you enter show env into gdb, it may not be correct when you actually execute the program because gdb executes $SHELL -c <program> to run the program. Try this as a test, run $SHELL from the command line and then echo $LD_LIBRARY_PATH. Is it correct? If not, then you probably need to add it to your rc (.tcshrc in my case).
I had a similar problem when trying to run gdb on windows 7. I use MobaXterm to access a Linux toolbox. I installed gdb separately from http://www.gnu.org/software/gdb/ . I got it to work by making sure gdb could find the correct .dll files as mentioned by Employed Russian. If you have MobaXterm installed the .dll files should appear in your home directory in MobaXterm/slash/bin.
gdb however did not recognize the LD_LIBRARY_PATH variable. For me, it worked when I used the PATH variable instead:
(gdb) set env PATH C:\Users\Joshua\Documents\MobaXterm\slash\bin
(gdb) run
I would think using PATH instead of LD_LIBRARY_PATH might work for you provided you put the correct path to your library.
gdb is looking for a library, so why are you concerned with the include path? You may want to try to set the gdb option "solib-search-path" to point to the location of the libcudart.so.5.0 library.
I'm working on RHEL WS 4.5.
I've obtained the glibc source rpm matching this system, opened it to get its contents using rpm2cpio.
Working in that tree, I've created a patch to mtrace.c (i want to add more stack backtrace levels) and incorporated it in the spec file and created a new set of RPMs including the debuginfo rpms.
I installed all of these on a test vm (created from the same RH base image) and can confirm that my changes are included.
But with more complex executions, I crash in mtrace.c ... but gdb can't find the debug information so I don't get line number info and I can't actually debug the failure.
Based on dates, I think I can confirm that the debug information is installed on the test system in /usr/src/debug/glibc-2.3.6/
I tried
sharedlibrary libc*
in gdb and it tells me the symbols are already loaded.
My test includes a locally built python and full symbols are found for python.
My sense is that perhaps glibc isn't being built under rpmbuild with debug enabled. I've reviewed the glibc.spec file and even built with
_enable_debug_packages
defined as 1 which looked like it might influence the result. My review of the configure scripts invoked during the rpmbuild build step didn't give me any hints.
Hmmmm .. just found /usr/lib/debug/lib/libc-2.3.4.so.debug
and /usr/lib/debug/lib/tls/i486/libc-2.3.4.so.debug
but both of these are reported as stripped by the file command.
It appears that you are installing non-matching RPMs:
/usr/src/debug/glibc-2.3.6
just found /usr/lib/debug/lib/libc-2.3.4.so.debug
There are not for the same version; there is no way they came from the same -debuginfo RPM.
both of these are reported as stripped by the file command.
These should not show as stripped. Either they were not built correctly, or your strip is busted.
Also note that you don't actually have to get all of this working to debug your problem. In the RPMBUILD directory, you should be able to find the glibc build directory, with full-debug libc.so.6. Just copy that library into your VM, and you wouldn't have to worry about the debuginfo RPM.
Try verifying that debug info for mtrace.c is indeed present. First see if the separate debug info for GLIBC knows about a compilation unit called mtrace.c:
$ eu-readelf -w /usr/lib/debug/lib64/libc-2.15.so.debug > t
$ grep mtrace t
name (strp) "mtrace.c"
name (strp) "mtrace"
1 0 0 0 mtrace.c
[10480] "mtrace.c"
[104bb] "mtrace"
[5052] symbol: mtrace, CUs: 446
Then see if GDB actually finds the source file from the glibc-debuginfo RPM:
(gdb) set pagination off
(gdb) start # pause your test program right after main()
(gdb) set logging on
Copying output to gdb.txt.
(gdb) info sources
Quit GDB then grep for mtrace in gdb.txt and you should find something like /usr/src/debug/glibc-2.15-a316c1f/malloc/mtrace.c
This works with GDB 7.4. I'm not sure the GDB version shipped with RHEL 4.5 supports all the command used above. Building upstream GDB from source is in fact easier than Python though.
When trying to add strack traces to mtrace, make sure you don't call malloc() directly or indirectly in the GLIBC malloc hooks.