May be related to old bug https://bugzilla.redhat.com/show_bug.cgi?id=485734
The error appeared when system froze for 30-60 seconds (log timestamps before the freeze were earlier so I don't know the exact moment the system froze, only timestamps for the moment it automatically continue to run again).
The only error message found in journalctl was this (hostname is "desktop"):
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: snd_pcm_delay() returned a value that is exceptionally large: -377464 bytes (-2139 ms).
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: Most likely this is a bug in the ALSA driver 'snd_hda_intel'. Please report this issue to the ALSA developers.
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: snd_pcm_dump():
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: Soft volume PCM
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: Control: PCM Playback Volume
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: min_dB: -51
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: max_dB: 0
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: resolution: 256
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: Its setup is:
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: stream : PLAYBACK
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: access : MMAP_INTERLEAVED
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: format : S16_LE
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: subformat : STD
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: channels : 2
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: rate : 44100
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: exact rate : 44100 (44100/1)
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: msbits : 16
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: buffer_size : 16384
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: period_size : 8192
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: period_time : 185759
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: tstamp_mode : ENABLE
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: tstamp_type : MONOTONIC
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: period_step : 1
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: avail_min : 15802
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: period_event : 0
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: start_threshold : -1
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: stop_threshold : 4611686018427387904
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: silence_threshold: 0
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: silence_size : 0
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: boundary : 4611686018427387904
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: Slave: Hardware PCM card 0 'HDA Intel PCH' device 0 subdevice 0
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: Its setup is:
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: stream : PLAYBACK
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: access : MMAP_INTERLEAVED
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: format : S16_LE
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: subformat : STD
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: channels : 2
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: rate : 44100
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: exact rate : 44100 (44100/1)
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: msbits : 16
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: buffer_size : 16384
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: period_size : 8192
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: period_time : 185759
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: tstamp_mode : ENABLE
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: tstamp_type : MONOTONIC
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: period_step : 1
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: avail_min : 15802
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: period_event : 0
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: start_threshold : -1
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: stop_threshold : 4611686018427387904
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: silence_threshold: 0
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: silence_size : 0
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: boundary : 4611686018427387904
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: appl_ptr : 667758626
2021-06-14T15:28:59+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: hw_ptr : 667852992
2021-06-14T15:29:02+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-sink.c: ALSA woke us up to write new data to the device, but there was actually nothing to write.
2021-06-14T15:29:02+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-sink.c: Most likely this is a bug in the ALSA driver 'snd_hda_intel'. Please report this issue to the ALSA developers.
2021-06-14T15:29:02+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-sink.c: We were woken up with POLLOUT set -- however a subsequent snd_pcm_avail() returned 0 or another value < min_avail.
Note the NEGATIVE output from snd_pcm_delay() which matches the old bug https://bugzilla.redhat.com/show_bug.cgi?id=485734
This happened very near the same time as freeze that I reported in bug 1931871 so I don't know if this is the cause of the kernel freeze or the consequence.
I also had similar error earlier in the same log where the returned value is positive and makes sense for simply having too high latency:
2021-06-14T15:27:25+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: snd_pcm_avail() returned a value that is exceptionally large: 382816 bytes (2170 ms).
2021-06-14T15:27:25+0300 desktop pulseaudio[2472]: [alsa-sink-ALC892 Analog] alsa-util.c: Most likely this is a bug in the ALSA driver 'snd_hda_intel'. Please report this issue to the ALSA developers.
The 2170 ms delay is more than expected if the kernel memory management is frozen as I assume is the cause for https://bugs.launchpad.net/ubuntu/+source/linux-meta-hwe-5.4/+bug/1931871
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-modules-5.4.0-74-lowlatency 5.4.0-74.83~18.04.1
ProcVersionSignature: Ubuntu 5.4.0-74.83~18.04.1-lowlatency 5.4.114
Uname: Linux 5.4.0-74-lowlatency x86_64
ApportVersion: 2.20.9-0ubuntu7.24
Architecture: amd64
CurrentDesktop: MATE
Date: Tue Jun 15 10:22:29 2021
Dependencies:
EcryptfsInUse: Yes
InstallationDate: Installed on 2019-01-05 (891 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
SourcePackage: linux-hwe-5.4
UpgradeStatus: No upgrade log present (probably fresh install)
