GDB is Unable to find libthread_db

GDB is Unable to find libthread_db

[Attila Lendvai]

dear Guixers,

i'm trying to debug:


https://issues.guix.gnu.org/58191


which is essentally that gpaste sigsegv's:


$ gpaste-client --version
(/home/alendvai/.guix-home/profile/bin/gpaste-client:6955): GPaste-CRITICAL **: 21:23:48.100: Error calling StartServiceByName for org.gnome.GPaste: Process org.gnome.GPaste received signal 11


but the error happens in a thread, and GDB is unable to find 'libthread_db matching inferior's thread library':



$ gdb --args ./src/client/gpaste-client --version
GNU gdb (GDB) 12.1

[...]

Warning: /gnu/store/frcfl9lbc5pijlnfgd8c02ynvlp19qqv-gpaste-3.34.4-checkout: No such file or directory.
Reading symbols from ./src/client/gpaste-client...
(gdb) set auto-load safe-path /
(gdb) r
Starting program: /home/alendvai/workspace/gpaste/builddir/src/client/gpaste-client --version
warning: Unable to find libthread_db matching inferior's thread library, thread debugging will not be available.
[New LWP 7206]
[New LWP 7207]

(/home/alendvai/workspace/gpaste/builddir/src/client/gpaste-client:7203): GPaste-CRITICAL **: 21:25:48.822: Error calling StartServiceByName for org.gnome.GPaste: Process org.gnome.GPaste received signal 11

[LWP 7206 exited]
[LWP 7203 exited]
[LWP 7207 exited]
[New process 7203]
[Inferior 1 (process 7203) exited with code 01]
(gdb) 


the same question was asked on guix-help (https://lists.gnu.org/archive/html/help-guix/2022-09/msg00003.html) but without any answers.

any hints on how to proceed?

my primary goal is to fix gpaste, which a tool that i use(d) daily. getting at least a backtrace from GDB to see where the error originates from would probably give me some hints.

-- 
• attila lendvai
• PGP: 963F 5D5F 45C7 DFCD 0A39
--
“Life is dear, love is dearer. Both can be given up for freedom.”
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Re: GDB is Unable to find libthread_db

[Ludovic Courtès]

Hi,

Attila Lendvai <attila@lendvai.name> skribis:

> $ gpaste-client --version
> (/home/alendvai/.guix-home/profile/bin/gpaste-client:6955): GPaste-CRITICAL **: 21:23:48.100: Error calling StartServiceByName for org.gnome.GPaste: Process org.gnome.GPaste received signal 11

FWIW I’m unable to reproduce this problem:

--8<---------------cut here---------------start------------->8---
$ guix describe
Generation 239  Dec 04 2022 23:46:31    (current)
  guix b2a848d
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: master
    commit: b2a848d23d37f31496e1ff664f1dcf6abcdcc388
$ guix shell gpaste -- gpaste-client --version
GPaste 42.1
--8<---------------cut here---------------end--------------->8---

> (gdb) r
> Starting program: /home/alendvai/workspace/gpaste/builddir/src/client/gpaste-client --version
> warning: Unable to find libthread_db matching inferior's thread library, thread debugging will not be available.

I’m not sure under which circumstances this error happens.

It works for me though, as in:

--8<---------------cut here---------------start------------->8---
$ guix shell gdb guile guile:debug -- gdb --args guile
GNU gdb (GDB) 12.1

[...]

Type "apropos word" to search for commands related to "word"...
Reading symbols from guile...
Reading symbols from /gnu/store/9snhi90f2nivxqrvqgjgixdch5zkps88-guile-3.0.8-debug/lib/debug//gnu/store/qlmpcy5zi84m6dikq3fnx5dz38qpczlc-guile-3.0.8/bin/guile.debug...
(gdb) r
Starting program: /gnu/store/dyw73lrvdnffwsp5idrcznyn0k0fzywz-profile/bin/guile 
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/gnu/store/5h2w4qi9hk1qzzgi1w83220ydslinr4s-glibc-2.33/lib/libthread_db.so.1".
[New Thread 0x7ffff75bf640 (LWP 20252)]
[New Thread 0x7ffff6dbe640 (LWP 20253)]
[New Thread 0x7ffff65bd640 (LWP 20254)]
[New Thread 0x7ffff5666640 (LWP 20255)]
[New Thread 0x7ffff422d640 (LWP 20256)]
GNU Guile 3.0.8
--8<---------------cut here---------------end--------------->8---

One situation where it doesn’t work is if the process being debugged is
in a namespace different from that of GDB, but that doesn’t seem to be
what you did, so I’m not sure.

Ludo’.

Re: GDB is Unable to find libthread_db

[Attila Lendvai]

thanks for looking into it Ludo!

looking again at the error message, it actually means that dbus was unable to start the daemon (but the daemon's error output was swallowed by the architecture).


$ /gnu/store/6i4gi0sfbssv9g6yd28jgnb18219zk7h-gpaste-42.1/libexec/gpaste/gpaste-daemon

(gpaste-daemon:14604): GLib-GIO-CRITICAL **: 12:44:11.196: g_settings_schema_source_lookup: assertion 'source != NULL' failed
Segmentation fault


it was enough of a hint for me to fix gpaste:

https://issues.guix.gnu.org/59863

looking at the code, i have no idea why/how it was not crashing for you.


as for the GDB issue:

> $ guix shell gdb guile guile:debug -- gdb --args guile

surprisingly enough, the above fails for me:

$ guix shell gdb guile guile:debug -- gdb --args guile
GNU gdb (GDB) 12.1
[...]
Reading symbols from guile...
(No debugging symbols found in guile)
(gdb) r
Starting program: /gnu/store/dyw73lrvdnffwsp5idrcznyn0k0fzywz-profile/bin/guile
warning: File "/gnu/store/qlmpcy5zi84m6dikq3fnx5dz38qpczlc-guile-3.0.8/lib/libguile-3.0.so.1.5.0-gdb.scm" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
To enable execution of this file add
[...]
warning: Unable to find libthread_db matching inferior's thread library, thread debugging will not be available.


maybe you have something installed in your profile that i don't? it's not a roadblock anymore, though.


> One situation where it doesn’t work is if the process being debugged is
> in a namespace different from that of GDB, but that doesn’t seem to be
> what you did, so I’m not sure.


i don't even know how to do that, so hopefully i'm not doing that. :)

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• attila lendvai
• PGP: 963F 5D5F 45C7 DFCD 0A39
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