broken sudo vclog -m output

Start by reproducing the issue with repeated sudo vclog -m commands on the Raspberry Pi environment described, and compare the output with the final intact sample in the report. Inspect the vclog -m entry point and the related log-handling path; done means repeated invocations consistently produce complete, readable log lines rather than corrupted output.

Describe the bug

The output of the command sudo vclog -m very often is broken. See log for example

Steps to reproduce the behaviour

1. Open console
2. run command sudo vclog -m many times

Expected result: all attempt should give correct output

Actual result: in most cases the output is broken (see log for example)

Device (s)

Raspberry Pi 4 Mod. B

System

$ cat /etc/rpi-issue
Raspberry Pi reference 2023-09-22
Generated using pi-gen, https://github.com/RPi-Distro/pi-gen, 40f37458ae7cadea1aec913ae10b5e7008ebce0a, stage4

$ vcgencmd version
Apr 26 2024 18:18:11 
Copyright (c) 2012 Broadcom
version f1a80576d5322dde60a2e7e9e3f4b56fd5fbe18d (clean) (release) (start)

$ uname -a
Linux raspi 6.6.30-v8+ #1 SMP PREEMPT Wed May 15 15:36:33 UTC 2024 aarch64 GNU/Linux

Logs

$ sudo vclog -m
1830825.008: ailed+�
1768383.858: de=7) failedn���
1869488.235: d)i鴡
1601463.137: (space=3291328, in_low_region=0, mode=7) failedr���
1767990.816: 
691486.053: .֡
1763716.152: gion=0, mode=7) failed�Uߡ
544108.320:  (buffer header callback not defined)��
809332.335: ) failed�*�
1701209.717:  callback not defined)����
000000.081: compact_internal(space=3291328, in_low_region=0, mode=7) failed��
678191.470: 91328, in_low_region=0, mode=7) failed8��
1634561.280: port_event_send: event lost on port 1,0 (buffer header callback not defined)ʣ�
544502.639: 1,0 (buffer header callback not defined)r!�

$ sudo vclog -m
1830825.008: ailed(�i�
1768383.858: de=7) failed�4�
1869488.235: d)�x�
1601463.137: (space=3291328, in_low_region=0, mode=7) failed(1��
1767990.816: 
pi@raspi:~ $ sudo vclog -m
1830825.008: ailed�훢
1768383.858: de=7) failed
                         �!�
1869488.235: d)��%�
1601463.137: (space=3291328, in_low_region=0, mode=7) failed��.�
1767990.816: 

$ sudo vclog -m
1830825.008: ailed*���
1768383.858: de=7) failed��?�
1869488.235: d)��C�
1601463.137: (space=3291328, in_low_region=0, mode=7) failed��L�
1767990.816: 
539768.882: egion=0, mode=7) failed��f�
926770.532: �pp�
1801675.106: ined)1�x�
1828716.800: l_port_event_send: event lost on port 1,0 (buffer header callback not defined)���
1700754.546: d: event lost on port 1,0 (buffer header callback not defined)���
1932029.025: 1328, in_low_region=0, mode=7) failed@+��
��01080.941: edf
1667330.157: al(space=3291328, in_low_region=0, mode=7) failedn�
1953392.991: ace=3291328, in_low_region=0, mode=7) failed�_��
1953722.220:  1,0 (buffer header callback not defined)&ů�

$ sudo vclog -m
1830825.008: ailed��Ӣ
1768383.858: de=7) failedj�Y�
1869488.235: d))�]�
1601463.137: (space=3291328, in_low_region=0, mode=7) failedT�f�
1767990.816: 
1767990.816: 
1701322.866: lback not defined)䛂�
540699.745: t_event_send: event lost on port 1,0 (buffer header callback not defined)����
1702257.952: on port 1,0 (buffer header callback not defined)o���
2672462.180: 
942814.001: _region=0, mode=7) failed����
1601071.392: on=0, mode=7) failed7���
000065.536: mpact_internal(space=3291328, in_low_region=0, mode=7) failed<׹�
1634561.280: port_event_send: event lost on port 1,0 (buffer header callback not defined)S�â

$ sudo vclog -m
2726388.521: alloc_compact_internal(space=3291328, in_low_region=0, mode=7) failed
2726388.563: mmal: mmal_port_event_send: event lost on port 1,0 (buffer header callback not defined)
2726397.969: alloc_compact_internal(space=3291328, in_low_region=0, mode=7) failed
2726398.010: mmal: mmal_port_event_send: event lost on port 1,0 (buffer header callback not defined)
2726398.219: alloc_compact_internal(space=3291328, in_low_region=0, mode=7) failed
2726398.259: mmal: mmal_port_event_send: event lost on port 1,0 (buffer header callback not defined)
2726407.994: alloc_compact_internal(space=3291328, in_low_region=0, mode=7) failed
2726408.035: mmal: mmal_port_event_send: event lost on port 1,0 (buffer header callback not defined)
2726408.291: alloc_compact_internal(space=3291328, in_low_region=0, mode=7) failed
<...>

Additional context

No response