Hi Simon, Thanks for your quick answer! I run GDB like this: gdb --args ./babeltrace2 /home/aron/Schreibtisch/kernel4 -o text (I'm in src/cli/.libs)
I don't think I've ever installed a System Version of babeltrace2, so it is really weird that GDB uses following library: 0x00007ffff7f36f00 0x00007ffff7f89749 Yes (*) /lib/x86_64-linux-gnu/libbabeltrace2.so.0 (*): Shared library is missing debugging information. And you're absolutely right! That is the reason why I can't debug it. Is there a way to specify the library path? Because even with the libtool wrapper, GDB uses the release version of libbabeltrace2.so.0. You're helping me a lot, thank you! :) I hope you have a great day! Kind regards, Aron __________ Aron Seidl DH-Student IT Education Carl Zeiss AG Carl-Zeiss-Strasse 22 73447 Oberkochen, Deutschland aron.se...@zeiss.com http://www.zeiss.de/ __________ Carl Zeiss AG Sitz der Gesellschaft: Oberkochen, Deutschland Vorsitzender des Aufsichtsrates: Dr. Michael Bolle Vorstand: Dr. Karl Lamprecht (Vorsitzender), Susan-Stefanie Breitkopf, Sven Hermann, Dr. Christian Müller, Andreas Pecher, Dr. Jochen Peter, Dr. Markus Weber Amtsgericht Ulm, HRB 501 555, USt-IdNr: DE 811 119 940 -----Ursprüngliche Nachricht----- Von: Simon Marchi <sim...@simark.ca> Gesendet: Dienstag, 24. Oktober 2023 20:52 An: Seidl, Aron <aron.se...@zeiss.com>; lttng-dev@lists.lttng.org Betreff: Re: [lttng-dev] Debugging Libaries in Babeltrace 2 On 10/24/23 11:52, Seidl, Aron via lttng-dev wrote: > Hello guys, > I'm currently a student at the company Carl Zeiss in Oberkochen Germany. I'd > like to trace the Kernel from our CMM-Controller with CTF and convert it to > plain text, like Babeltrace 2 does. To understand how Babeltrace 2 works with > CTF, I debug the code. Hi Aron, :w > > > However when I try to step into a function which is included via the extern > Babeltrace 2 library (e.g. *bt_graph_run(ctx.graph)* in graph.c), the GNU > Compiler steps over the function and I'm unable to look into this function. > > > > I figured, it is because the Debugger cannot find the Debug Symbols even > though I compile everything with Debug-Symbols and no compiler optimization. > > I configure the Makefile as follows: > > > > BABELTRACE_DEV_MODE=1 BABELTRACE_MINIMAL_LOG_LEVEL=TRACE > BABELTRACE_DEBUG_MODE=1 CFLAGS='-g -O0' CPPFLAGS='-g -O0' LDFLAGS='-g > -O0' ./configure You probably mean CXXFLAGS, not CPPFLAGS. CXXFLAGS are flags to be passed to the C++ compiler, CPPFLAGS are flags to be passed to the preprocessor. It's probably going to work anyway, since preprocessor flags are passed when compiling, but I wanted to point it out because it looks like a mistake. > > > > For test purposes, I implemented the function *bt_graph_run(NULL) *inside a > new project to check, if I could step into the function with my debugger, or > whether it is a general problem with my machine. > > That actually worked and I was able to step into the function, but not with > the normal Babeltrace 2 project. > > None of my colleagues could explain this behavior, so my question now is, how > do you guys debug the code? Is there a different way you debug these > functions, or do I configure my project the wrong way? > > > > I appreciate it if someone can help me and tell me how to configure the > project so that the code is debugable. Can you please show how you start and run babeltrace2 under GDB? My guess is that you end up using a system version of libbabeltrace2.so from a package you installed or something. In GDB, do "info shared" and see what the libbabeltrace2.so line looks like. It should be like this, with a path in your build directory. There should be no asterisk indicating that the debug info is missing. 0x00007ffff75a87f0 0x00007ffff76f5990 Yes /home/smarchi/build/babeltrace/src/lib/.libs/libbabeltrace2.so.0 Since we are using libtool, the src/cli/babeltrace2 file is actually a libtool script that sets up the right environment (LD_LIBRARY_PATH and stuff) for running the real babeltrace2 binary (found at src/cli/.libs/babeltrace2) directly in the build tree. The proper way to debug it is with the libtool wrapper: $ libtool --mode=execute gdb -q --args src/cli/babeltrace2 /home/smarchi/src/babeltrace/tests/data/ctf-traces/1/succeed/sequence Reading symbols from /home/smarchi/build/babeltrace/src/cli/.libs/babeltrace2... (gdb) b bt_graph_run Function "bt_graph_run" not defined. Make breakpoint pending on future shared library load? (y or [n]) y Breakpoint 1 (bt_graph_run) pending. (gdb) r Starting program: /home/smarchi/build/babeltrace/src/cli/.libs/babeltrace2 /home/smarchi/src/babeltrace/tests/data/ctf-traces/1/succeed/sequence [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". Breakpoint 1, bt_graph_run (graph=0x6120000025c0) at /home/smarchi/src/babeltrace/src/lib/graph/graph.c:683 683 BT_ASSERT_PRE_NO_ERROR(); See: https://www.gnu.org/software/libtool/manual/html_node/Debugging-executables.html Simon _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
