Failed to receive file descriptors - strange messages when attaching to the container

Hey
I have an following issue when I’m running funtoo 1.4 amd64 Linux container:

┌─[doskanoness@gentoo] - [~] - [2022-01-29 10:20:27]
└─[0] <> lxc-attach -n mycontainer /bin/bash                                                                                                                                  ⚡[▶▶▶▶▶▶▶▶▶▷]
lxc-attach: mycontainer: af_unix.c: lxc_abstract_unix_recv_fds_iov: 316 Invalid argument - Received no file descriptors
lxc-attach: mycontainer: commands.c: lxc_cmd_rsp_recv_fds: 127 Failed to receive file descriptors
mycontainer / # ping google.pl
PING google.pl (142.250.203.131) 56(84) bytes of data.
64 bytes from waw07s06-in-f3.1e100.net (142.250.203.131): icmp_seq=1 ttl=55 time=20.9 ms
64 bytes from waw07s06-in-f3.1e100.net (142.250.203.131): icmp_seq=2 ttl=55 time=14.2 ms
64 bytes from waw07s06-in-f3.1e100.net (142.250.203.131): icmp_seq=3 ttl=55 time=11.8 ms
^C
--- google.pl ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 11.821/15.622/20.858/3.826 ms
mycontainer / # exit
exit
┌─[doskanoness@gentoo] - [~] - [2022-01-29 10:20:41]
└─[0] <> lxc-info -n mycontainer                                                                                                                                              ⚡[▶▶▶▶▶▶▶▶▶▷]
Name:           mycontainer
State:          RUNNING
PID:            2565
IP:             192.168.150.180
Link:           veth1000_NPxK
 TX bytes:      3.73 KiB
 RX bytes:      95.46 KiB
 Total bytes:   99.19 KiB

LXC version: 4.0.11
I have ZFS on root
Why do I get these messages? What’s wrong?

lxc-attach: mycontainer: af_unix.c: lxc_abstract_unix_recv_fds_iov: 316 Invalid argument - Received no file descriptors
lxc-attach: mycontainer: commands.c: lxc_cmd_rsp_recv_fds: 127 Failed to receive file descriptors

Thanks

This info might be useful:

┌─[doskanoness@gentoo] - [~] - [2022-01-31 02:07:00]
└─[0] <> lxc-ls                                                                                                                                                               ⚡[▶▶▶▶▶▶▶▶▶▷]
┌─[doskanoness@gentoo] - [~] - [2022-01-31 02:07:02]
└─[0] <> lxc-create -n mycontainer -t download                                                                                                                                ⚡[▶▶▶▶▶▶▶▶▶▷]
Setting up the GPG keyring
Downloading the image index

---
DIST    RELEASE ARCH    VARIANT BUILD
---
almalinux       8       amd64   default 20220130_23:08
almalinux       8       arm64   default 20220130_23:08
alpine  3.12    amd64   default 20220130_13:12
alpine  3.12    arm64   default 20220130_13:00
alpine  3.12    armhf   default 20220130_13:12
alpine  3.12    i386    default 20220130_13:12
alpine  3.12    ppc64el default 20220130_13:12
alpine  3.12    s390x   default 20220130_13:12
alpine  3.13    amd64   default 20220130_13:12
alpine  3.13    arm64   default 20220130_13:01
alpine  3.13    armhf   default 20220130_13:00
alpine  3.13    i386    default 20220130_13:12
alpine  3.13    ppc64el default 20220130_13:12
alpine  3.13    s390x   default 20220130_13:12
alpine  3.14    amd64   default 20220130_13:00
alpine  3.14    arm64   default 20220130_13:00
alpine  3.14    armhf   default 20220130_13:00
alpine  3.14    i386    default 20220130_13:12
alpine  3.14    ppc64el default 20220130_13:12
alpine  3.14    s390x   default 20220130_13:12
alpine  3.15    amd64   default 20220130_13:12
alpine  3.15    arm64   default 20220130_13:00
alpine  3.15    armhf   default 20220130_13:00
alpine  3.15    i386    default 20220130_13:00
alpine  3.15    ppc64el default 20220130_13:12
alpine  3.15    s390x   default 20220130_13:12
alpine  edge    amd64   default 20220130_13:12
alpine  edge    arm64   default 20220130_13:00
alpine  edge    armhf   default 20220130_13:00
alpine  edge    i386    default 20220130_13:00
alpine  edge    ppc64el default 20220130_13:12
alpine  edge    s390x   default 20220130_13:12
alt     Sisyphus        amd64   default 20220131_01:49
alt     Sisyphus        arm64   default 20220131_01:17
alt     Sisyphus        armhf   default 20220131_01:50
alt     Sisyphus        i386    default 20220131_01:17
alt     Sisyphus        ppc64el default 20220131_01:17
alt     p10     amd64   default 20220131_01:17
alt     p10     arm64   default 20220131_01:18
alt     p10     armhf   default 20220131_01:49
alt     p10     i386    default 20220131_01:17
alt     p10     ppc64el default 20220131_01:17
alt     p9      amd64   default 20220131_01:18
alt     p9      arm64   default 20220131_01:18
alt     p9      armhf   default 20220131_01:17
alt     p9      i386    default 20220131_01:17
alt     p9      ppc64el default 20220131_01:17
amazonlinux     current amd64   default 20220131_05:09
amazonlinux     current arm64   default 20220131_05:09
apertis v2019   amd64   default 20220131_10:53
apertis v2019   arm64   default 20220131_10:54
apertis v2019   armhf   default 20220131_10:54
apertis v2020   amd64   default 20220131_10:53
apertis v2020   arm64   default 20220131_10:54
apertis v2020   armhf   default 20220131_10:53
apertis v2021   amd64   default 20220131_10:53
apertis v2021   arm64   default 20220131_10:54
apertis v2021   armhf   default 20220131_10:54
archlinux       current amd64   default 20220131_04:18
archlinux       current arm64   default 20220131_04:18
archlinux       current armhf   default 20220131_04:18
busybox 1.34.1  amd64   default 20220131_06:00
busybox 1.34.1  arm64   default 20220131_06:00
centos  7       amd64   default 20220131_07:08
centos  7       arm64   default 20220131_07:08
centos  7       armhf   default 20220131_07:08
centos  7       i386    default 20220131_07:08
centos  7       ppc64el default 20220131_07:08
centos  8-Stream        amd64   default 20220131_07:08
centos  8-Stream        arm64   default 20220131_07:08
centos  8-Stream        ppc64el default 20220131_07:08
centos  9-Stream        amd64   default 20220131_07:08
centos  9-Stream        arm64   default 20220131_07:08
centos  9-Stream        ppc64el default 20220131_07:08
debian  bookworm        amd64   default 20220131_05:24
debian  bookworm        arm64   default 20220131_05:25
debian  bookworm        armel   default 20220131_05:25
debian  bookworm        armhf   default 20220131_05:25
debian  bookworm        i386    default 20220131_05:25
debian  bookworm        ppc64el default 20220131_05:32
debian  bookworm        s390x   default 20220131_05:31
debian  bullseye        amd64   default 20220131_05:24
debian  bullseye        arm64   default 20220131_05:25
debian  bullseye        armel   default 20220131_05:25
debian  bullseye        armhf   default 20220131_05:25
debian  bullseye        i386    default 20220131_05:24
debian  bullseye        ppc64el default 20220131_05:24
debian  bullseye        s390x   default 20220131_05:24
debian  buster  amd64   default 20220131_05:24
debian  buster  arm64   default 20220131_05:25
debian  buster  armel   default 20220131_05:25
debian  buster  armhf   default 20220131_05:25
debian  buster  i386    default 20220131_05:24
debian  buster  ppc64el default 20220131_05:24
debian  buster  s390x   default 20220131_05:24
debian  sid     amd64   default 20220131_05:24
debian  sid     arm64   default 20220131_05:24
debian  sid     armel   default 20220131_05:25
debian  sid     armhf   default 20220131_05:25
debian  sid     i386    default 20220131_05:24
debian  sid     ppc64el default 20220131_05:24
debian  sid     s390x   default 20220131_05:24
debian  stretch amd64   default 20220131_05:24
debian  stretch arm64   default 20220131_05:25
debian  stretch armel   default 20220131_05:24
debian  stretch armhf   default 20220131_05:24
debian  stretch i386    default 20220131_05:24
debian  stretch ppc64el default 20220131_05:24
debian  stretch s390x   default 20220131_05:24
devuan  ascii   amd64   default 20220131_11:50
devuan  ascii   arm64   default 20220131_11:51
devuan  ascii   armel   default 20220131_11:51
devuan  ascii   armhf   default 20220130_11:51
devuan  ascii   i386    default 20220131_11:51
devuan  beowulf amd64   default 20220131_11:50
devuan  beowulf arm64   default 20220130_11:50
devuan  beowulf armel   default 20220130_11:50
devuan  beowulf armhf   default 20220131_11:50
devuan  beowulf i386    default 20220131_11:50
devuan  beowulf ppc64el default 20220131_11:50
devuan  chimaera        amd64   default 20220131_11:50
devuan  chimaera        arm64   default 20220131_11:51
devuan  chimaera        armel   default 20220130_11:50
devuan  chimaera        armhf   default 20220130_11:50
devuan  chimaera        i386    default 20220131_11:51
devuan  chimaera        ppc64el default 20220131_11:50
fedora  34      amd64   default 20220130_20:33
fedora  34      arm64   default 20220130_20:33
fedora  34      armhf   default 20220130_20:33
fedora  34      ppc64el default 20220130_20:33
fedora  34      s390x   default 20220130_20:33
fedora  35      amd64   default 20220130_20:33
fedora  35      arm64   default 20220130_20:33
fedora  35      armhf   default 20220130_20:33
fedora  35      s390x   default 20220130_20:33
funtoo  1.4     amd64   default 20220130_16:45
funtoo  1.4     armhf   default 20220130_16:45
funtoo  1.4     i386    default 20220130_16:45
kali    current amd64   default 20220130_17:14
kali    current arm64   default 20220130_17:46
kali    current armel   default 20220130_17:15
kali    current armhf   default 20220130_17:16
kali    current i386    default 20220130_17:14
mint    tara    amd64   default 20220131_08:51
mint    tara    i386    default 20220131_08:51
mint    tessa   amd64   default 20220131_08:51
mint    tessa   i386    default 20220131_08:51
mint    tina    amd64   default 20220131_08:51
mint    tina    i386    default 20220131_09:22
mint    tricia  amd64   default 20220131_08:51
mint    tricia  i386    default 20220131_08:51
mint    ulyana  amd64   default 20220131_08:51
mint    ulyssa  amd64   default 20220131_08:51
mint    uma     amd64   default 20220131_08:51
mint    una     amd64   default 20220131_08:51
opensuse        15.3    amd64   default 20220131_04:20
opensuse        15.3    arm64   default 20220131_04:20
opensuse        15.3    ppc64el default 20220131_04:20
opensuse        15.3    s390x   default 20220131_04:20
opensuse        tumbleweed      amd64   default 20220131_04:20
opensuse        tumbleweed      arm64   default 20220131_04:20
opensuse        tumbleweed      i386    default 20220131_04:20
opensuse        tumbleweed      ppc64el default 20220131_04:20
opensuse        tumbleweed      s390x   default 20220131_04:20
openwrt 19.07   amd64   default 20220131_11:58
openwrt 19.07   arm64   default 20220131_12:08
openwrt 19.07   armhf   default 20220131_11:59
openwrt 21.02   amd64   default 20220131_11:57
openwrt 21.02   arm64   default 20220131_11:59
openwrt 21.02   armhf   default 20220130_12:00
openwrt snapshot        amd64   default 20220131_11:57
openwrt snapshot        arm64   default 20220131_11:58
openwrt snapshot        armhf   default 20220131_11:58
oracle  7       amd64   default 20220131_09:00
oracle  7       arm64   default 20220131_09:01
oracle  8       amd64   default 20220131_09:01
oracle  8       arm64   default 20220131_07:46
plamo   6.x     amd64   default 20220131_01:33
plamo   6.x     i386    default 20220131_01:33
plamo   7.x     amd64   default 20220131_01:33
pld     current amd64   default 20220130_20:46
pld     current i386    default 20220130_20:46
rockylinux      8       amd64   default 20220131_02:06
rockylinux      8       arm64   default 20220131_02:06
springdalelinux 7       amd64   default 20220131_07:00
springdalelinux 7       i386    default 20220131_06:38
springdalelinux 8       amd64   default 20220131_06:38
ubuntu  bionic  amd64   default 20220131_07:42
ubuntu  bionic  arm64   default 20220131_09:01
ubuntu  bionic  armhf   default 20220131_09:02
ubuntu  bionic  i386    default 20220129_07:42
ubuntu  bionic  ppc64el default 20220129_07:42
ubuntu  bionic  s390x   default 20220129_07:42
ubuntu  focal   amd64   default 20220131_07:42
ubuntu  focal   arm64   default 20220131_07:42
ubuntu  focal   armhf   default 20220131_09:02
ubuntu  focal   ppc64el default 20220129_07:42
ubuntu  focal   s390x   default 20220129_07:42
ubuntu  hirsute amd64   default 20220131_07:42
ubuntu  hirsute arm64   default 20220130_10:27
ubuntu  hirsute armhf   default 20220131_09:02
ubuntu  hirsute ppc64el default 20220131_09:01
ubuntu  hirsute s390x   default 20220129_07:42
ubuntu  impish  amd64   default 20220131_07:42
ubuntu  impish  arm64   default 20220130_08:45
ubuntu  impish  armhf   default 20220131_09:02
ubuntu  impish  ppc64el default 20220129_07:42
ubuntu  impish  s390x   default 20220129_07:52
ubuntu  jammy   amd64   default 20220131_07:42
ubuntu  jammy   arm64   default 20220130_08:40
ubuntu  jammy   armhf   default 20220131_09:02
ubuntu  jammy   ppc64el default 20220129_07:42
ubuntu  jammy   s390x   default 20220129_07:42
ubuntu  xenial  amd64   default 20220131_07:43
ubuntu  xenial  arm64   default 20220131_07:43
ubuntu  xenial  armhf   default 20220131_09:02
ubuntu  xenial  i386    default 20220129_07:42
ubuntu  xenial  ppc64el default 20220129_07:42
ubuntu  xenial  s390x   default 20220129_07:51
voidlinux       current amd64   default 20220130_17:10
voidlinux       current arm64   default 20220130_17:11
voidlinux       current armhf   default 20220130_17:10
voidlinux       current i386    default 20220130_17:10
---

Distribution: 
funtoo
Release: 
1.4
Architecture: 
amd64

Using image from local cache
Unpacking the rootfs

---
You just created an Funtoo 1.4 generic_64 (20220129_16:45) container.
┌─[doskanoness@gentoo] - [~] - [2022-01-31 02:07:51]
└─[0] <> lxc-start -n mycontainer                                                                                                                                             ⚡[▶▶▶▶▶▶▶▶▶▷]
┌─[doskanoness@gentoo] - [~] - [2022-01-31 02:08:11]
└─[0] <> lxc-attach -n mycontainer -l trace -o debug /bin/bash                                                                                                                ⚡[▶▶▶▶▶▶▶▶▶▷]
lxc-attach: mycontainer: af_unix.c: lxc_abstract_unix_recv_fds_iov: 316 Invalid argument - Received no file descriptors
lxc-attach: mycontainer: commands.c: lxc_cmd_rsp_recv_fds: 127 Failed to receive file descriptors
mycontainer / # exyit
bash: exyit: command not found
mycontainer / # exit
exit
┌─[doskanoness@gentoo] - [~] - [2022-01-31 02:08:20]
└─[127] <> cat debug                                                                                                                                                          ⚡[▶▶▶▶▶▶▶▶▶▷]
lxc-attach mycontainer 20220131130817.968 INFO     confile - confile.c:set_config_idmaps:2069 - Read uid map: type u nsid 0 hostid 100000 range 65536
lxc-attach mycontainer 20220131130817.968 INFO     confile - confile.c:set_config_idmaps:2069 - Read uid map: type g nsid 0 hostid 100000 range 65536
lxc-attach mycontainer 20220131130817.968 DEBUG    commands - commands.c:lxc_cmd_rsp_recv_fds:147 - Command "get_init_pid" received response
lxc-attach mycontainer 20220131130817.968 TRACE    commands - commands.c:lxc_cmd:516 - Opened new command socket connection fd 4 for command "get_init_pid"
lxc-attach mycontainer 20220131130817.968 DEBUG    commands - commands.c:lxc_cmd_rsp_recv_fds:136 - Received exact number of file descriptors 1 == 1
lxc-attach mycontainer 20220131130817.968 DEBUG    commands - commands.c:lxc_cmd_rsp_recv:250 - Finished processing "get_init_pidfd" with file descriptor 6
lxc-attach mycontainer 20220131130817.968 TRACE    commands - commands.c:lxc_cmd:516 - Opened new command socket connection fd 5 for command "get_init_pidfd"
lxc-attach mycontainer 20220131130817.968 DEBUG    commands - commands.c:lxc_cmd_rsp_recv_fds:147 - Command "get_clone_flags" received response
lxc-attach mycontainer 20220131130817.968 TRACE    commands - commands.c:lxc_cmd:516 - Opened new command socket connection fd 5 for command "get_clone_flags"
lxc-attach mycontainer 20220131130817.968 INFO     attach - attach.c:get_attach_context:414 - Container does not run in a separate core scheduling domain
lxc-attach mycontainer 20220131130817.968 TRACE    attach - attach.c:get_attach_context:434 - Container process still running and PID was not recycled
lxc-attach mycontainer 20220131130817.968 TRACE    attach - attach.c:pidfd_setns_supported:377 - Attaching to namespaces via pidfds unsupported
lxc-attach mycontainer 20220131130817.968 TRACE    attach - attach.c:get_attach_context:442 - Attaching to namespaces via pidfds not supported
lxc-attach mycontainer 20220131130817.968 TRACE    attach - attach.c:parse_init_status:330 - Container's init process runs with hostuid 100000
lxc-attach mycontainer 20220131130817.968 TRACE    attach - attach.c:parse_init_status:337 - Container's init process runs with hostgid 100000
lxc-attach mycontainer 20220131130817.968 TRACE    attach - attach.c:userns_setup_ids:246 - Container has mapping for uid 0
lxc-attach mycontainer 20220131130817.968 TRACE    attach - attach.c:userns_setup_ids:266 - Container has mapping for gid 0
lxc-attach mycontainer 20220131130817.968 INFO     lsm - lsm/lsm.c:lsm_init_static:38 - Initialized LSM security driver nop
lxc-attach mycontainer 20220131130817.968 WARN     attach - attach.c:get_attach_context:477 - No security context received
lxc-attach mycontainer 20220131130817.968 DEBUG    commands - commands.c:lxc_cmd_rsp_recv_fds:147 - Command "get_config_item" received response
lxc-attach mycontainer 20220131130817.969 TRACE    commands - commands.c:lxc_cmd:516 - Opened new command socket connection fd 6 for command "get_config_item"
lxc-attach mycontainer 20220131130817.969 DEBUG    commands - commands.c:lxc_cmd_rsp_recv_fds:147 - Command "get_config_item" received response
lxc-attach mycontainer 20220131130817.969 TRACE    commands - commands.c:lxc_cmd:516 - Opened new command socket connection fd 6 for command "get_config_item"
lxc-attach mycontainer 20220131130817.969 DEBUG    seccomp - seccomp.c:parse_config_v2:656 - Host native arch is [3221225534]
lxc-attach mycontainer 20220131130817.969 TRACE    seccomp - seccomp.c:get_new_ctx:470 - Added arch 2 to main seccomp context
lxc-attach mycontainer 20220131130817.969 TRACE    seccomp - seccomp.c:get_new_ctx:478 - Removed native arch from main seccomp context
lxc-attach mycontainer 20220131130817.969 TRACE    seccomp - seccomp.c:get_new_ctx:470 - Added arch 3 to main seccomp context
lxc-attach mycontainer 20220131130817.969 TRACE    seccomp - seccomp.c:get_new_ctx:478 - Removed native arch from main seccomp context
lxc-attach mycontainer 20220131130817.969 TRACE    seccomp - seccomp.c:get_new_ctx:483 - Arch 4 already present in main seccomp context
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:parse_config_v2:807 - Processing "reject_force_umount  # comment this to allow umount -f;  not recommended"
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:524 - Set seccomp rule to reject force umounts
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:524 - Set seccomp rule to reject force umounts
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:524 - Set seccomp rule to reject force umounts
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:parse_config_v2:807 - Processing "[all]"
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:parse_config_v2:807 - Processing "kexec_load errno 1"
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:564 - Adding native rule for syscall[246:kexec_load] action[327681:errno] arch[0]
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:564 - Adding compat rule for syscall[246:kexec_load] action[327681:errno] arch[1073741827]
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:564 - Adding compat rule for syscall[246:kexec_load] action[327681:errno] arch[1073741886]
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:parse_config_v2:807 - Processing "open_by_handle_at errno 1"
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:564 - Adding native rule for syscall[304:open_by_handle_at] action[327681:errno] arch[0]
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:564 - Adding compat rule for syscall[304:open_by_handle_at] action[327681:errno] arch[1073741827]
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:564 - Adding compat rule for syscall[304:open_by_handle_at] action[327681:errno] arch[1073741886]
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:parse_config_v2:807 - Processing "init_module errno 1"
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:564 - Adding native rule for syscall[175:init_module] action[327681:errno] arch[0]
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:564 - Adding compat rule for syscall[175:init_module] action[327681:errno] arch[1073741827]
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:564 - Adding compat rule for syscall[175:init_module] action[327681:errno] arch[1073741886]
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:parse_config_v2:807 - Processing "finit_module errno 1"
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:564 - Adding native rule for syscall[313:finit_module] action[327681:errno] arch[0]
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:564 - Adding compat rule for syscall[313:finit_module] action[327681:errno] arch[1073741827]
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:564 - Adding compat rule for syscall[313:finit_module] action[327681:errno] arch[1073741886]
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:parse_config_v2:807 - Processing "delete_module errno 1"
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:564 - Adding native rule for syscall[176:delete_module] action[327681:errno] arch[0]
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:564 - Adding compat rule for syscall[176:delete_module] action[327681:errno] arch[1073741827]
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:do_resolve_add_rule:564 - Adding compat rule for syscall[176:delete_module] action[327681:errno] arch[1073741886]
lxc-attach mycontainer 20220131130817.969 INFO     seccomp - seccomp.c:parse_config_v2:1017 - Merging compat seccomp contexts into main context
lxc-attach mycontainer 20220131130817.969 TRACE    seccomp - seccomp.c:parse_config_v2:1027 - Merged first compat seccomp context into main context
lxc-attach mycontainer 20220131130817.969 TRACE    seccomp - seccomp.c:parse_config_v2:1043 - Merged second compat seccomp context into main context
lxc-attach mycontainer 20220131130817.969 INFO     attach - attach.c:fetch_seccomp:1090 - Retrieved seccomp policy
lxc-attach mycontainer 20220131130817.969 DEBUG    commands - commands.c:lxc_cmd_rsp_recv_fds:147 - Command "get_config_item" received response
lxc-attach mycontainer 20220131130817.969 TRACE    commands - commands.c:lxc_cmd:516 - Opened new command socket connection fd 6 for command "get_config_item"
lxc-attach mycontainer 20220131130817.969 DEBUG    commands - commands.c:lxc_cmd_rsp_recv_fds:136 - Received exact number of file descriptors 1 == 1
lxc-attach mycontainer 20220131130817.969 DEBUG    commands - commands.c:lxc_cmd_rsp_recv:250 - Finished processing "get_devpts_fd" with file descriptor 14
lxc-attach mycontainer 20220131130817.969 TRACE    commands - commands.c:lxc_cmd:516 - Opened new command socket connection fd 13 for command "get_devpts_fd"
lxc-attach mycontainer 20220131130817.969 DEBUG    terminal - terminal.c:lxc_terminal_peer_default:702 - Using terminal "/dev/tty" as proxy
lxc-attach mycontainer 20220131130817.969 TRACE    terminal - terminal.c:lxc_terminal_signal_init:144 - Created signal fd 17
lxc-attach mycontainer 20220131130817.969 DEBUG    terminal - terminal.c:lxc_terminal_winsz:59 - Set window size to 189 columns and 20 rows
lxc-attach mycontainer 20220131130817.969 TRACE    attach - attach.c:lxc_attach:1659 - Transient process 2857 started initializing
lxc-attach mycontainer 20220131130817.969 ERROR    af_unix - af_unix.c:lxc_abstract_unix_recv_fds_iov:316 - Invalid argument - Received no file descriptors
lxc-attach mycontainer 20220131130817.969 ERROR    commands - commands.c:lxc_cmd_rsp_recv_fds:127 - Failed to receive file descriptors
lxc-attach mycontainer 20220131130817.969 TRACE    commands - commands.c:lxc_cmd:516 - Opened new command socket connection fd 6 for command "get_cgroup_ctx"
lxc-attach mycontainer 20220131130817.969 DEBUG    commands - commands.c:lxc_cmd_get_cgroup_ctx:762 - Invalid argument - Failed to process "get_cgroup_ctx"
lxc-attach mycontainer 20220131130817.969 DEBUG    commands - commands.c:lxc_cmd_rsp_recv_fds:147 - Command "get_cgroup2_fd" received response
lxc-attach mycontainer 20220131130817.969 DEBUG    commands - commands.c:lxc_cmd_rsp_recv:250 - Finished processing "get_cgroup2_fd" with file descriptor -9
lxc-attach mycontainer 20220131130817.969 TRACE    commands - commands.c:lxc_cmd:516 - Opened new command socket connection fd 6 for command "get_cgroup2_fd"
lxc-attach mycontainer 20220131130817.969 DEBUG    commands - commands.c:lxc_cmd_get_cgroup2_fd:1775 - Invalid argument - Failed to receive file descriptor for "get_cgroup2_fd"
lxc-attach mycontainer 20220131130817.969 INFO     cgfsng - cgroups/cgfsng.c:legacy_hierarchy_delegated:3057 - Permission denied - Legacy hierarchy not writable, skipping
lxc-attach mycontainer 20220131130817.969 INFO     cgfsng - cgroups/cgfsng.c:legacy_hierarchy_delegated:3057 - Permission denied - Legacy hierarchy not writable, skipping
lxc-attach mycontainer 20220131130817.970 INFO     cgfsng - cgroups/cgfsng.c:legacy_hierarchy_delegated:3057 - Permission denied - Legacy hierarchy not writable, skipping
lxc-attach mycontainer 20220131130817.970 INFO     cgfsng - cgroups/cgfsng.c:legacy_hierarchy_delegated:3057 - Permission denied - Legacy hierarchy not writable, skipping
lxc-attach mycontainer 20220131130817.970 INFO     cgfsng - cgroups/cgfsng.c:legacy_hierarchy_delegated:3057 - Permission denied - Legacy hierarchy not writable, skipping
lxc-attach mycontainer 20220131130817.970 INFO     cgfsng - cgroups/cgfsng.c:legacy_hierarchy_delegated:3057 - Permission denied - Legacy hierarchy not writable, skipping
lxc-attach mycontainer 20220131130817.970 INFO     cgfsng - cgroups/cgfsng.c:legacy_hierarchy_delegated:3057 - Permission denied - Legacy hierarchy not writable, skipping
lxc-attach mycontainer 20220131130817.970 INFO     cgfsng - cgroups/cgfsng.c:legacy_hierarchy_delegated:3057 - Permission denied - Legacy hierarchy not writable, skipping
lxc-attach mycontainer 20220131130817.970 INFO     cgfsng - cgroups/cgfsng.c:legacy_hierarchy_delegated:3057 - Permission denied - Legacy hierarchy not writable, skipping
lxc-attach mycontainer 20220131130817.970 INFO     cgfsng - cgroups/cgfsng.c:legacy_hierarchy_delegated:3057 - Permission denied - Legacy hierarchy not writable, skipping
lxc-attach mycontainer 20220131130817.970 INFO     cgfsng - cgroups/cgfsng.c:legacy_hierarchy_delegated:3057 - Permission denied - Legacy hierarchy not writable, skipping
lxc-attach mycontainer 20220131130817.970 INFO     cgfsng - cgroups/cgfsng.c:legacy_hierarchy_delegated:3057 - Permission denied - Legacy hierarchy not writable, skipping
lxc-attach mycontainer 20220131130817.970 INFO     cgfsng - cgroups/cgfsng.c:legacy_hierarchy_delegated:3057 - Permission denied - Legacy hierarchy not writable, skipping
lxc-attach mycontainer 20220131130817.970 INFO     cgfsng - cgroups/cgfsng.c:legacy_hierarchy_delegated:3057 - Permission denied - Legacy hierarchy not writable, skipping
lxc-attach mycontainer 20220131130817.970 INFO     cgfsng - cgroups/cgfsng.c:unified_hierarchy_delegated:3044 - Permission denied - The cgroup.threads file is not writable, skipping unified hierarchy
lxc-attach mycontainer 20220131130817.970 TRACE    cgroup - cgroups/cgroup.c:cgroup_init:40 - Initialized cgroup driver cgfsng
lxc-attach mycontainer 20220131130817.970 WARN     cgroup - cgroups/cgroup.c:cgroup_init:49 - Unsupported cgroup layout
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:lxc_attach:1691 - Moved transient process 2857 into container cgroup
lxc-attach mycontainer 20220131130817.970 TRACE    conf - conf.c:setup_proc_filesystem:3339 - Setup /proc/2857 settings
lxc-attach mycontainer 20220131130817.970 TRACE    mainloop - mainloop.c:__epoll_open:489 - Created epoll instance
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:lxc_attach:1716 - Initialized terminal mainloop
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:lxc_attach:1723 - Told transient process to start initializing
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:attach_namespaces:685 - Attaching to user namespace
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:attach_namespaces:685 - Attaching to mnt namespace
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:attach_namespaces:685 - Attaching to pid namespace
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:attach_namespaces:685 - Attaching to uts namespace
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:attach_namespaces:685 - Attaching to ipc namespace
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:attach_namespaces:685 - Attaching to net namespace
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:attach_namespaces:685 - Attaching to cgroup namespace
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:attach_namespaces:692 - Inheriting time namespace
lxc-attach mycontainer 20220131130817.970 WARN     attach - attach.c:lxc_attach:1603 - Could not change directory to "/home/doskanoness"
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:lxc_attach:1637 - Attached process 2858 started initializing
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:lxc_attach:1729 - Received pid 2858 of attached process in parent pid namespace
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:do_attach:1199 - Set new personality
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:lxc_attach:1742 - Transient process 2857 exited
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:do_attach:1208 - Dropped capabilities
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:do_attach:1221 - Set up environment
lxc-attach mycontainer 20220131130817.970 NOTICE   utils - utils.c:lxc_drop_groups:1347 - Dropped supplimentary groups
lxc-attach mycontainer 20220131130817.970 NOTICE   utils - utils.c:lxc_switch_uid_gid:1323 - Switched to gid 0
lxc-attach mycontainer 20220131130817.970 NOTICE   utils - utils.c:lxc_switch_uid_gid:1332 - Switched to uid 0
lxc-attach mycontainer 20220131130817.970 TRACE    attach - attach.c:do_attach:1335 - Prepared terminal file descriptor 15
lxc-attach mycontainer 20220131130817.970 TRACE    utils - utils.c:fix_stdio_permissions:1833 - Operation not permitted - Failed to chown standard I/O file descriptor 0 to uid -1 and gid 5
lxc-attach mycontainer 20220131130817.970 TRACE    utils - utils.c:fix_stdio_permissions:1833 - Operation not permitted - Failed to chown standard I/O file descriptor 1 to uid -1 and gid 5
lxc-attach mycontainer 20220131130817.970 TRACE    utils - utils.c:fix_stdio_permissions:1833 - Operation not permitted - Failed to chown standard I/O file descriptor 2 to uid -1 and gid 5
lxc-attach mycontainer 20220131130817.970 INFO     attach - attach.c:do_attach:1351 - Failed to adjust stdio permissions
#
# pseudo filter code start
#
# filter for arch x86_64 (3221225534)
if ($arch == 3221225534)
  # filter for syscall "finit_module" (313) [priority: 65535]
  if ($syscall == 313)
    action ERRNO(1);
  # filter for syscall "open_by_handle_at" (304) [priority: 65535]
  if ($syscall == 304)
    action ERRNO(1);
  # filter for syscall "kexec_load" (246) [priority: 65535]
  if ($syscall == 246)
    action ERRNO(1);
  # filter for syscall "delete_module" (176) [priority: 65535]
  if ($syscall == 176)
    action ERRNO(1);
  # filter for syscall "init_module" (175) [priority: 65535]
  if ($syscall == 175)
    action ERRNO(1);
  # filter for syscall "umount2" (166) [priority: 65533]
  if ($syscall == 166)
    if ($a1.hi32 & 0x00000000 == 0)
      if ($a1.lo32 & 0x00000001 == 1)
        action ERRNO(13);
  # default action
  action ALLOW;
# filter for arch x86 (1073741827)
if ($arch == 1073741827)
  # filter for syscall "finit_module" (350) [priority: 65535]
  if ($syscall == 350)
    action ERRNO(1);
  # filter for syscall "open_by_handle_at" (342) [priority: 65535]
  if ($syscall == 342)
    action ERRNO(1);
  # filter for syscall "kexec_load" (283) [priority: 65535]
  if ($syscall == 283)
    action ERRNO(1);
  # filter for syscall "delete_module" (129) [priority: 65535]
  if ($syscall == 129)
    action ERRNO(1);
  # filter for syscall "init_module" (128) [priority: 65535]
  if ($syscall == 128)
    action ERRNO(1);
  # filter for syscall "umount2" (52) [priority: 65534]
  if ($syscall == 52)
    if ($a1 & 0x00000001 == 1)
      action ERRNO(13);
  # default action
  action ALLOW;
# filter for arch x32 (3221225534)
if ($arch == 3221225534)
  # filter for syscall "kexec_load" (1073742352) [priority: 65535]
  if ($syscall == 1073742352)
    action ERRNO(1);
  # filter for syscall "finit_module" (1073742137) [priority: 65535]
  if ($syscall == 1073742137)
    action ERRNO(1);
  # filter for syscall "open_by_handle_at" (1073742128) [priority: 65535]
  if ($syscall == 1073742128)
    action ERRNO(1);
  # filter for syscall "delete_module" (1073742000) [priority: 65535]
  if ($syscall == 1073742000)
    action ERRNO(1);
  # filter for syscall "init_module" (1073741999) [priority: 65535]
  if ($syscall == 1073741999)
    action ERRNO(1);
  # filter for syscall "umount2" (1073741990) [priority: 65534]
  if ($syscall == 1073741990)
    if ($a1 & 0x00000001 == 1)
      action ERRNO(13);
  # default action
  action ALLOW;
# invalid architecture action
action KILL;
#
# pseudo filter code end
#
lxc-attach mycontainer 20220131130817.971 TRACE    attach - attach.c:do_attach:1358 - Loaded seccomp profile
lxc-attach mycontainer 20220131130820.540 INFO     terminal - terminal.c:lxc_terminal_ptx_io_handler:390 - Terminal client on fd 13 has exited

missing - - in lxc-attach argument? i think it should be
lxc-attach -n mycontainer - - /bin/bash

┌─[doskanoness@gentoo] - [~] - [2022-02-07 09:05:06]
└─[0] <> lxc-attach -n mycontainer -- /bin/bash                                                                                                                               ⚡[▶▶▶▶▶▶▶▶▶▷]
lxc-attach: mycontainer: af_unix.c: lxc_abstract_unix_recv_fds_iov: 316 Invalid argument - Received no file descriptors
lxc-attach: mycontainer: commands.c: lxc_cmd_rsp_recv_fds: 127 Failed to receive file descriptors
mycontainer / #

I know what’s wrong. The problem lies in cgroups. Thread is solved.