How to attach Valgrind to kded6 daemon

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1

I need to debug kded6 daemon process with Valgrind (https://bugs.kde.org/show_bug.cgi?id=522489). So far, Valgrind or kded6 via CLI seem to work, but not both of them together. To clarify, I always shutdown kded6 with systemctl --user stop plasma-kded6.service and kill $(pidof kded6).

plasma-kded6.service starts kded6 by using the full path /usr/bin/kded6, with no arguments.

If I start kded6, it works just like it’s supposed to do, like a daemon.
However, if I run valgrind --trace-children=yes --track-origins=yes kded6 it exits immediately, without user input. Since I’m trying to debug a failure on user event, I need it to persist for some extra time.

❯ kded6
org.kde.libkbolt: Failed to connect to Bolt manager DBus interface: 
org.kde.bolt.kded: Couldn't connect to Bolt DBus daemon
kf.modemmanagerqt: Failed enumerating MM objects: "org.freedesktop.DBus.Error.NameHasNoOwner" 
 "Could not activate remote peer 'org.freedesktop.ModemManager1': activation request failed: unknown unit"
xsettingsd: Reloading configuration
xsettingsd: Loaded 16 settings from /home/echedey/.config/xsettingsd/xsettingsd.conf
kf.bluezqt: PendingCall Error: "Failed"
^C⏎                                                                                                                                                                                         
~ 8s
❯ valgrind --log-file=/tmp/debug.log --trace-children=yes --track-origins=yes kded6
kded6: CPU ISA level is lower than required

~
❯ cat /tmp/debug.log
==14530== Memcheck, a memory error detector
==14530== Copyright (C) 2002-2024, and GNU GPL'd, by Julian Seward et al.
==14530== Using Valgrind-3.25.1 and LibVEX; rerun with -h for copyright info
==14530== Command: kded6
==14530== Parent PID: 3231
==14530== 
==14530== 
==14530== HEAP SUMMARY:
==14530==     in use at exit: 0 bytes in 0 blocks
==14530==   total heap usage: 0 allocs, 0 frees, 0 bytes allocated
==14530== 
==14530== All heap blocks were freed -- no leaks are possible
==14530== 
==14530== For lists of detected and suppressed errors, rerun with: -s
==14530== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

I don’t know why this happens nor how to disable this behavior. TIA. I’m happy to provide further information if needed.

2

Nevermind, the issue was on my side.
kded6 reports the following: CPU ISA level is lower than required. That’s an error that stops it from continuing. This happened to me because I’m in CachyOS, using the optimized repo v4 for kded6 but glibc (for the ld.so) from core (bare Arch repo) with its related glibc-debug for the debug symbols needed to use valgrind.

Edit: the solution was to switch to kded from the core repo.