I didn't find the BT that helpful... Although it's possible I've completely forgotten everything I previously knew about gdb and I need to relearn everything from the ground up. I'm perplexed by the BT because the first of the steps it shows on the way to the segfault is for main.cpp:79.
> (gdb) bt > #0 xcb_get_setup (c=0x0) at /usr/src/debug/libxcb-1.13.1-7.fc34.x86_64/src/xcb_conn.c:314 > #1 0x00007ffff7f77bd0 in xcb_ewmh_init_atoms (c=<optimized out>, ewmh=0x756540) at /usr/src/debug/xcb-util-wm-0.4.1-20.fc34.x86_64/ewmh/ewmh.c:605 > #2 0x000000000048db12 in LXCB::LXCB (this=this@entry=0x756540) at ../libLumina/LuminaX11.cpp:44 > #3 0x00000000004ab991 in LSession::LSession (this=this@entry=0x7fffffffd9e0, argc=@0x7fffffffd9ac: 1, argv=argv@entry=0x7fffffffdc18) at LSession.cpp:60 > #4 0x0000000000445555 in main (argc=<optimized out>, argv=0x7fffffffdc18) at main.cpp:79 OK Great, except the main.cpp of the program I'm debugging only has 27 lines. https://github.com/lumina-desktop/lumina/blob/master/src-qt5/desktop-utils/lumina-screenshot/main.cpp So I'm guessing that's a differnet main, and thus I need to figure out how I get from the main in the utility I'm running to whatever that main is. This is why I was hoping I could just dump everything to a file and then walk the entire process step by step. Yes I know I'd get a ton of info I dont need, but at least then I dont have any questions as to what led to what. Thanks for the info, I'll see if I glean anything from the links you posted. On Tue, Dec 28, 2021 at 8:48 AM Ben Beasley <c...@musicinmybrain.net> wrote: > Is the backtrace not helpful in figuring out where to set up > breakpoints? As in, “gdb foo”, then “run”, wait for the crash, and type > “bt”? > > The darktable development documentation suggests[1] the following to log > useful backtraces: > > |$ gdb darktable ... crash dt here ... (gdb) set pagination off > (gdb) set logging file gdb.txt (gdb) set logging on (gdb) thread > apply all bt full| > > If you need to do this non-interactively, you can combine it with gdb’s > batch mode. Strangely, I have a spec file that demonstrates this [2]. > The debugbreak package is a header-only C library that implements > programmatic breakpoints, so the natural way to test it is with the > debugger. > > Hopefully some of that is helpful. > > – Ben > > [1] https://www.darktable.org/development/ > > [2] > > https://src.fedoraproject.org/rpms/debugbreak/blob/e009ccfac2b8e05a6018921ed6d3e732837a9e52/f/debugbreak.spec#_62 > > On 12/28/21 08:08, JT wrote: > > Hey all, > > I havent used gdb in a while, so I'm trying to knock the rust off my > > knowledge and pick up a few more skills. > > I'm trying to track down an issue in the Lumina Desktop. One of the > > utilities (lumina-screenshot) segfaults when starting up and I'm > > trying to deduce why. The problem is that it gets pretty far into the > > program starting before it finally dies and I havent been able to step > > through gdb enough manually to find that point. > > > > Is there a way to run gdb in a capture mode of some kind and dump the > > output entirely like I can do with strace? > > I kinda need to know where it's crashing to have an idea of where to > > set up breakpoints. > > > > Unless my memory is off, I was sure there was a way to do this but I > > just can't seem to remember or figure out how to do it. > > > > Any pointers? Thanks! > > > > JT > > > > _______________________________________________ > > devel mailing list -- devel@lists.fedoraproject.org > > To unsubscribe send an email to devel-le...@lists.fedoraproject.org > > Fedora Code of Conduct: > https://docs.fedoraproject.org/en-US/project/code-of-conduct/ > > List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines > > List Archives: > https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org > > Do not reply to spam on the list, report it: > https://pagure.io/fedora-infrastructure > _______________________________________________ > devel mailing list -- devel@lists.fedoraproject.org > To unsubscribe send an email to devel-le...@lists.fedoraproject.org > Fedora Code of Conduct: > https://docs.fedoraproject.org/en-US/project/code-of-conduct/ > List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines > List Archives: > https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org > Do not reply to spam on the list, report it: > https://pagure.io/fedora-infrastructure >
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