Comment 4 for bug 1933254

On 22.04, I saw similar issue after a few apt upgrade, which trigger zsys service etc.
the zsysd will consume much more memory than it should do. and no response when apt requesting.
here is a typical result:

root@zymElite:~# apt-get update;apt-get dist-upgrade
Hit:1 http://dl.google.com/linux/chrome/deb stable InRelease
Hit:2 http://packages.microsoft.com/repos/edge stable InRelease
Hit:3 http://archive.ubuntu.com/ubuntu jammy InRelease
Get:4 http://archive.ubuntu.com/ubuntu jammy-updates InRelease [109 kB]
Hit:5 https://ppa.launchpadcontent.net/agornostal/ulauncher/ubuntu jammy InRelease
Get:6 http://archive.ubuntu.com/ubuntu jammy-backports InRelease [99.8 kB]
Get:7 http://archive.ubuntu.com/ubuntu jammy-security InRelease [110 kB]
Get:8 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 Packages [277 kB]
Get:9 http://archive.ubuntu.com/ubuntu jammy-updates/main i386 Packages [124 kB]
Get:10 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 DEP-11 Metadata [73.4 kB]
Get:11 http://archive.ubuntu.com/ubuntu jammy-updates/universe i386 Packages [46.3 kB]
Get:12 http://archive.ubuntu.com/ubuntu jammy-updates/universe amd64 Packages [116 kB]
Get:13 http://archive.ubuntu.com/ubuntu jammy-updates/universe Translation-en [40.1 kB]
Get:14 http://archive.ubuntu.com/ubuntu jammy-updates/universe amd64 DEP-11 Metadata [92.0 kB]
Get:15 http://archive.ubuntu.com/ubuntu jammy-updates/universe amd64 c-n-f Metadata [2,344 B]
Get:16 http://archive.ubuntu.com/ubuntu jammy-backports/universe amd64 DEP-11 Metadata [1,192 B]
Get:17 http://archive.ubuntu.com/ubuntu jammy-security/main amd64 DEP-11 Metadata [11.4 kB]
Get:18 http://archive.ubuntu.com/ubuntu jammy-security/universe amd64 c-n-f Metadata [1,128 B]
Fetched 1,104 kB in 5s (229 kB/s)
Reading package lists... Done
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Calculating upgrade... Done
The following packages will be upgraded:
  deja-dup
1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 298 kB of archives.
After this operation, 8,192 B of additional disk space will be used.
Do you want to continue? [Y/n]
Get:1 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 deja-dup amd64 42.9-1ubuntu3 [298 kB]
Fetched 298 kB in 2s (149 kB/s)
ERROR Service took too long to respond. Disconnecting client.
(Reading database ... 288053 files and directories currently installed.)
Preparing to unpack .../deja-dup_42.9-1ubuntu3_amd64.deb ...
Unpacking deja-dup (42.9-1ubuntu3) over (42.9-1ubuntu2) ...
Setting up deja-dup (42.9-1ubuntu3) ...
Processing triggers for desktop-file-utils (0.26-1ubuntu3) ...
Processing triggers for hicolor-icon-theme (0.17-2) ...
Processing triggers for gnome-menus (3.36.0-1ubuntu3) ...
Processing triggers for libglib2.0-0:amd64 (2.72.1-1) ...
Processing triggers for libglib2.0-0:i386 (2.72.1-1) ...
Processing triggers for man-db (2.10.2-1) ...
Processing triggers for mailcap (3.70+nmu1ubuntu1) ...
ERROR Service took too long to respond. Disconnecting client.

the htop show zsysd used about 3G RES memory.

here is the /proc/status:

zym@zymElite:~$ cat /proc/3757/status
Name: zsysd
Umask: 0022
State: S (sleeping)
Tgid: 3757
Ngid: 0
Pid: 3757
PPid: 1
TracerPid: 0
Uid: 0 0 0 0
Gid: 0 0 0 0
FDSize: 128
Groups:
NStgid: 3757
NSpid: 3757
NSpgid: 3757
NSsid: 3757
VmPeak: 5643412 kB
VmSize: 5643412 kB
VmLck: 0 kB
VmPin: 0 kB
VmHWM: 3298728 kB
VmRSS: 3298728 kB
RssAnon: 3291108 kB
RssFile: 7620 kB
RssShmem: 0 kB
VmData: 3542848 kB
VmStk: 132 kB
VmExe: 5000 kB
VmLib: 6324 kB
VmPTE: 6784 kB
VmSwap: 0 kB
HugetlbPages: 0 kB
CoreDumping: 0
THP_enabled: 1
Threads: 23
SigQ: 1/254061
SigPnd: 0000000000000000
ShdPnd: 0000000000000000
SigBlk: 0000000000000000
SigIgn: 0000000000000000
SigCgt: fffffffd7fc1feff
CapInh: 0000000000000000
CapPrm: 000001ffffffffff
CapEff: 000001ffffffffff
CapBnd: 000001ffffffffff
CapAmb: 0000000000000000
NoNewPrivs: 1
Seccomp: 0
Seccomp_filters: 0
Speculation_Store_Bypass: thread vulnerable
SpeculationIndirectBranch: conditional enabled
Cpus_allowed: ffff
Cpus_allowed_list: 0-15
Mems_allowed: 00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000001
Mems_allowed_list: 0
voluntary_ctxt_switches: 89474
nonvoluntary_ctxt_switches: 63785

I think that zsysd may have very serious memory issue which will not func well in most case. So as other issues, we can see many with similar memory problem.

my case:
2TB zfs root, nearly half full. if you need my zfs status, please let me know.