Alt+PrtSc+REISUB doesn't shut down computer

The computer froze and then I held down Alt+PrtSc and pressed R, E, I, S, U, B, one by one, but it didn't shut down. So I waited for some time and then again held down Alt+PrtSc and pressed R, E, I, S, U, B. Then it turned to a black screen with a tiny white line on the top left corner. Then I did Alt+PrtSc+REISUB several times, and there was no visible response. I held down the power button and shut it down. These are the last few lines of log before I powered off the computer: 11:17:53 kernel: sysrq: Keyboard mode set to system default 11:17:53 kernel: sysrq: Keyboard mode set to system default 11:15:38 kernel: sysrq: HELP : loglevel(0-9) reboot(b) crash(c) terminate-all-tasks(e) memory-full-oom-kill(f) kill-all-tasks(i) thaw-filesystems(j) sak(k) show-backtrace-all-active-cpus(l) show-memory-usage(m) nice-all-RT-tasks(n) poweroff(o) show-registers(p) show-all-timers(q) unraw(r) sync(s) show-task-states(t) unmount(u) force-fb(v) show-blocked-tasks(w) dump-ftrace-buffer(z) 11:15:35 kernel: sysrq: HELP : loglevel(0-9) reboot(b) crash(c) terminate-all-tasks(e) memory-full-oom-kill(f) kill-all-tasks(i) thaw-filesystems(j) sak(k) show-backtrace-all-active-cpus(l) show-memory-usage(m) nice-all-RT-tasks(n) poweroff(o) show-registers(p) show-all-timers(q) unraw(r) sync(s) show-task-states(t) unmount(u) force-fb(v) show-blocked-tasks(w) dump-ftrace-buffer(z) 11:15:31 kernel: sysrq: HELP : loglevel(0-9) reboot(b) crash(c) terminate-all-tasks(e) memory-full-oom-kill(f) kill-all-tasks(i) thaw-filesystems(j) sak(k) show-backtrace-all-active-cpus(l) show-memory-usage(m) nice-all-RT-tasks(n) poweroff(o) show-registers(p) show-all-timers(q) unraw(r) sync(s) show-task-states(t) unmount(u) force-fb(v) show-blocked-tasks(w) dump-ftrace-buffer(z) 11:15:26 kernel: sysrq: HELP : loglevel(0-9) reboot(b) crash(c) terminate-all-tasks(e) memory-full-oom-kill(f) kill-all-tasks(i) thaw-filesystems(j) sak(k) show-backtrace-all-active-cpus(l) show-memory-usage(m) nice-all-RT-tasks(n) poweroff(o) show-registers(p) show-all-timers(q) unraw(r) sync(s) show-task-states(t) unmount(u) force-fb(v) show-blocked-tasks(w) dump-ftrace-buffer(z) 11:15:20 kernel: sysrq: HELP : loglevel(0-9) reboot(b) crash(c) terminate-all-tasks(e) memory-full-oom-kill(f) kill-all-tasks(i) thaw-filesystems(j) sak(k) show-backtrace-all-active-cpus(l) show-memory-usage(m) nice-all-RT-tasks(n) poweroff(o) show-registers(p) show-all-timers(q) unraw(r) sync(s) show-task-states(t) unmount(u) force-fb(v) show-blocked-tasks(w) dump-ftrace-buffer(z) 11:15:15 kernel: sysrq: HELP : loglevel(0-9) reboot(b) crash(c) terminate-all-tasks(e) memory-full-oom-kill(f) kill-all-tasks(i) thaw-filesystems(j) sak(k) show-backtrace-all-active-cpus(l) show-memory-usage(m) nice-all-RT-tasks(n) poweroff(o) show-registers(p) show-all-timers(q) unraw(r) sync(s) show-task-states(t) unmount(u) force-fb(v) show-blocked-tasks(w) dump-ftrace-buffer(z) 11:15:00 kernel: sysrq: HELP : loglevel(0-9) reboot(b) crash(c) terminate-all-tasks(e) memory-full-oom-kill(f) kill-all-tasks(i) thaw-filesystems(j) sak(k) show-backtrace-all-active-cpus(l) show-memory-usage(m) nice-all-RT-tasks(n) poweroff(o) show-registers(p) show-all-timers(q) unraw(r) sync(s) show-task-states(t) unmount(u) force-fb(v) show-blocked-tasks(w) dump-ftrace-buffer(z) 11:14:57 kernel: sysrq: HELP : loglevel(0-9) reboot(b) crash(c) terminate-all-tasks(e) memory-full-oom-kill(f) kill-all-tasks(i) thaw-filesystems(j) sak(k) show-backtrace-all-active-cpus(l) show-memory-usage(m) nice-all-RT-tasks(n) poweroff(o) show-registers(p) show-all-timers(q) unraw(r) sync(s) show-task-states(t) unmount(u) force-fb(v) show-blocked-tasks(w) dump-ftrace-buffer(z) 11:14:56 kernel: sysrq: HELP : loglevel(0-9) reboot(b) crash(c) terminate-all-tasks(e) memory-full-oom-kill(f) kill-all-tasks(i) thaw-filesystems(j) sak(k) show-backtrace-all-active-cpus(l) show-memory-usage(m) nice-all-RT-tasks(n) poweroff(o) show-registers(p) show-all-timers(q) unraw(r) sync(s) show-task-states(t) unmount(u) force-fb(v) show-blocked-tasks(w) dump-ftrace-buffer(z) 11:12:05 kernel: ---[ end trace a43d1a9c4ed7a4a1 ]--- 11:12:05 kernel: Modules linked in: nls_iso8859_1 snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio snd_hda_intel snd_intel_dspcfg snd_intel_sdw_acpi intel_rapl_msr snd_hda_codec snd_hda_core snd_hwdep snd_pcm mei_hdcp intel_rapl_common intel_tcc_cooling x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm snd_seq_midi snd_seq_midi_event crct10dif_pclmul snd_rawmidi ghash_clmulni_intel aesni_intel crypto_simd cryptd rapl intel_cstate snd_seq snd_seq_device snd_timer i915 gigabyte_wmi wmi_bmof snd efi_pstore drm_kms_helper cec rc_core ee1004 i2c_algo_bit fb_sys_fops syscopyarea joydev input_leds soundcore mei_me sysfillrect sysimgblt mei mac_hid acpi_pad acpi_tad sch_fq_codel msr parport_pc ppdev drm lp parport ip_tables x_tables autofs4 hid_generic usbhid hid crc32_pclmul e1000e i2c_i801 nvme i2c_smbus nvme_core ahci xhci_pci libahci xhci_pci_renesas wmi video 11:12:05 kernel: 11:12:05 kernel: R13: 00007ffd70516ca8 R14: 00007f606a9e6018 R15: 00007ffd70516bb8 11:12:05 kernel: R10: 00007ffd7051d090 R11: 0000000000000293 R12: 0000000000000000 11:12:05 kernel: RBP: 00007ffd70516ca4 R08: 0000000000000000 R09: 0000000000000000 Despite the log shows "Keyboard mode set to system default", the computer didn't shut down, even after I had waited for several minutes. How do I make REISUB work? OS is Ubuntu 20.04.3 LTS. edit: These are the entries of syslog at about the time the freeze happened. 11:12:01 kernel: RAX: feff8d06657e1cc0 RBX: ffffe01c08836000 RCX: 0000000000000007 11:12:01 kernel: RSP: 0018:ffffaf8f8127bac0 EFLAGS: 00010202 11:12:01 kernel: Code: 3d 3d 01 48 29 c8 41 8b 48 20 89 c6 48 0f af f1 41 0f b6 48 24 48 c1 ee 20 29 f0 d3 e8 41 0f b6 48 25 01 f0 d3 e8 48 8d 04 c2 8b 20 4d 85 e4 0f 84 af 00 00 00 48 c7 00 00 00 00 00 41 8b 70 11:12:01 kernel: RIP: 0010:memcg_slab_free_hook+0x70/0x230 11:12:01 kernel: Hardware name: Gigabyte Technology Co., Ltd. B365 M AORUS ELITE/B365 M AORUS ELITE-CF, BIOS F2 08/13/2019 11:12:01 kernel: CPU: 0 PID: 1949 Comm: Socket Thread Not tainted 5.13.0-37-generic #42~20.04.1-Ubuntu 11:12:01 kernel: general protection fault, probably for non-canonical address 0xfeff8d06657e1cc0: 0000 [#1] SMP PTI Mar 26 10:45:19 gnome-shell: cr_parser_new_from_buf: assertion 'a_buf && a_len' failed Mar 26 10:45:19 gnome-shell: cr_declaration_parse_list_from_buf: assertion 'parser' failed Mar 26 10:45:19 gnome-shell: cr_parser_new_from_buf: assertion 'a_buf && a_len' failed Mar 26 10:45:19 gnome-shell: cr_declaration_parse_list_from_buf: assertion 'parser' failed Mar 26 10:45:19 gnome-shell: cr_parser_new_from_buf: assertion 'a_buf && a_len' failed Mar 26 10:45:19 gnome-shell: cr_declaration_parse_list_from_buf: assertion 'parser' failed Mar 26 10:45:19 gnome-shell: g_dbus_connection_emit_signal: assertion 'G_IS_DBUS_CONNECTION (connection)' failed Mar 26 10:45:19 gnome-shell: cr_parser_new_from_buf: assertion 'a_buf && a_len' failed Mar 26 10:45:19 gnome-shell: cr_declaration_parse_list_from_buf: assertion 'parser' failed Mar 26 11:03:49 dbus-daemon: [system] Activating via systemd: service name='net.reactivated.Fprint' unit='fprintd.service' requested by ':1.81' (uid=1000 pid=1517 comm="/usr/bin/gnome-shell " label="unconfined") Mar 26 11:03:49 systemd: Starting Fingerprint Authentication Daemon... Mar 26 11:03:49 dbus-daemon: [system] Successfully activated service 'net.reactivated.Fprint' Mar 26 11:03:49 systemd: Started Fingerprint Authentication Daemon. Mar 26 11:03:59 gnome-shell: cr_parser_new_from_buf: assertion 'a_buf && a_len' failed Mar 26 11:03:59 gnome-shell: cr_declaration_parse_list_from_buf: assertion 'parser' failed Mar 26 11:03:59 NetworkManager: [1648263839.2005] agent-manager: agent[7cccc8467972acfa,:1.81/org.gnome.Shell.NetworkAgent/1000]: agent registered Mar 26 11:03:59 dbus-daemon: [session uid=1000 pid=1311] Activating service name='org.freedesktop.FileManager1' requested by ':1.43' (uid=1000 pid=1517 comm="/usr/bin/gnome-shell " label="unconfined") Mar 26 11:03:59 gnome-shell: cr_parser_new_from_buf: assertion 'a_buf && a_len' failed Mar 26 11:03:59 gnome-shell: cr_declaration_parse_list_from_buf: assertion 'parser' failed Mar 26 11:03:59 dbus-daemon: [session uid=1000 pid=1311] Activating service name='org.gnome.Nautilus' requested by ':1.43' (uid=1000 pid=1517 comm="/usr/bin/gnome-shell " label="unconfined") Mar 26 11:03:59 gnome-shell: cr_parser_new_from_buf: assertion 'a_buf && a_len' failed Mar 26 11:03:59 gnome-shell: cr_declaration_parse_list_from_buf: assertion 'parser' failed Mar 26 11:03:59 gnome-shell: Window manager warning: Overwriting existing binding of keysym 31 with keysym 31 (keycode a). Mar 26 11:03:59 gnome-shell: Window manager warning: Overwriting existing binding of keysym 32 with keysym 32 (keycode b). Mar 26 11:03:59 gnome-shell: Window manager warning: Overwriting existing binding of keysym 38 with keysym 38 (keycode 11). Mar 26 11:03:59 gnome-shell: Window manager warning: Overwriting existing binding of keysym 39 with keysym 39 (keycode 12). Mar 26 11:03:59 gnome-shell: Window manager warning: Overwriting existing binding of keysym 33 with keysym 33 (keycode c). Mar 26 11:03:59 gnome-shell: Window manager warning: Overwriting existing binding of keysym 34 with keysym 34 (keycode d). Mar 26 11:03:59 gnome-shell: Window manager warning: Overwriting existing binding of keysym 35 with keysym 35 (keycode e). Mar 26 11:03:59 gnome-shell: Window manager warning: Overwriting existing binding of keysym 36 with keysym 36 (keycode f). Mar 26 11:03:59 gnome-shell: Window manager warning: Overwriting existing binding of keysym 37 with keysym 37 (keycode 10). Mar 26 11:04:19 systemd: fprintd.service: Succeeded. Mar 26 11:04:41 dbus-daemon: [session uid=1000 pid=1311] Activating service name='org.gnome.ControlCenter.SearchProvider' requested by ':1.43' (uid=1000 pid=1517 comm="/usr/bin/gnome-shell " label="unconfined") Mar 26 11:04:41 dbus-daemon: [session uid=1000 pid=1311] Activating service name='org.gnome.Nautilus' requested by ':1.43' (uid=1000 pid=1517 comm="/usr/bin/gnome-shell " label="unconfined") Mar 26 11:04:41 dbus-daemon: [session uid=1000 pid=1311] Activating service name='org.gnome.Calculator.SearchProvider' requested by ':1.43' (uid=1000 pid=1517 comm="/usr/bin/gnome-shell " label="unconfined") Mar 26 11:04:41 dbus-daemon: [session uid=1000 pid=1311] Activating service name='org.gnome.Calendar' requested by ':1.43' (uid=1000 pid=1517 com m="/usr/bin/gnome-shell " label="unconfined") Mar 26 11:04:41 dbus-daemon: [session uid=1000 pid=1311] Activating service name='org.gnome.Characters.BackgroundService' requested by ':1.43' (u id=1000 pid=1517 comm="/usr/bin/gnome-shell " label="unconfined") Mar 26 11:04:41 dbus-daemon: [session uid=1000 pid=1311] Activating service name='org.gnome.seahorse.Application' requested by ':1.43' (uid=1000 pid=1517 comm="/usr/bin/gnome-shell " label="unconfined") Mar 26 11:04:41 dbus-daemon: [session uid=1000 pid=1311] Activating via systemd: service name='org.gnome.Terminal' unit='gnome-terminal-server.se rvice' requested by ':1.43' (uid=1000 pid=1517 comm="/usr/bin/gnome-shell " label="uncon fined") Mar 26 11:04:41 systemd: Created slice apps.slice. Mar 26 11:04:41 systemd: Created slice apps-org.gnome.Ter minal.slice. Mar 26 11:04:41 systemd: Starting GNOME Terminal Server.. . Mar 26 11:04:41 dbus-daemon: [session uid=1000 pid=1311] Successfully activated service 'org.gnome.ControlCenter.SearchProvider' Mar 26 11:04:41 dbus-daemon: [session uid=1000 pid=1311] Successfully activated service 'org.gnome.seahorse.Application' Mar 26 11:04:41 dbus-daemon: [system] Activating via syste md: service name='org.freedesktop.timedate1' unit='dbus-org.freedesktop.timedate1.servic e' requested by ':1.184' (uid=1000 pid=5785 comm="/usr/bin/gnome-calendar --gapplication -service " label="unconfined") Mar 26 11:04:41 systemd: Starting Time & Date Service... Mar 26 11:04:41 dbus-daemon: [session uid=1000 pid=1311] Successfully activated service 'org.gnome.Terminal' Mar 26 11:04:41 systemd: Started GNOME Terminal Server. Mar 26 11:04:41 dbus-daemon: [session uid=1000 pid=1311] Successfully activated service 'org.gnome.Characters.BackgroundService' Mar 26 11:04:41 dbus-daemon: [system] Successfully activated service 'org.freedesktop.timedate1' Mar 26 11:04:41 systemd: Started Time & Date Service. Mar 26 11:04:41 dbus-daemon: [session uid=1000 pid=1311] Successfully activated service 'org.gnome.Calendar' Mar 26 11:04:41 dbus-daemon: [session uid=1000 pid=1311] Successfully activated service 'org.gnome.Nautilus' Mar 26 11:04:41 dbus-daemon: [session uid=1000 pid=1311] Successfully activated service 'org.gnome.Calculator.SearchProvider' Mar 26 11:04:43 dbus-daemon: [session uid=1000 pid=1311] Activating service name='org.gnome.gedit' requested by ':1.119' (uid=1000 pid=5780 comm="/usr/bin/nautilus --gapplication-service " label="unconfined") Mar 26 11:04:43 dbus-daemon: [session uid=1000 pid=1311] Successfully activated service 'org.gnome.gedit' Mar 26 11:04:48 dbus-daemon: [session uid=1000 pid=1311] Activating via systemd: service name='org.freedesktop.Tracker1' unit='tracker-store.service' requested by ':1.2' (uid=1000 pid=1308 comm="/usr/libexec/tracker-miner-fs " label="unconfined") Mar 26 11:04:48 systemd: Starting Tracker metadata database store and lookup manager... Mar 26 11:04:48 dbus-daemon: [session uid=1000 pid=1311] Successfully activated service 'org.freedesktop.Tracker1' Mar 26 11:04:48 systemd: Started Tracker metadata database store and lookup manager. Mar 26 11:04:48 dbus-daemon: [session uid=1000 pid=1311] Activating via systemd: service name='org.freedesktop.Tracker1.Miner.Extract' unit='tracker-extract.service' requested by ':1.2' (uid=1000 pid=1308 comm="/usr/libexec/tracker-miner-fs " label="unconfined") Mar 26 11:04:48 systemd: Starting Tracker metadata extractor... Mar 26 11:04:48 tracker-extract: Set scheduler policy to SCHED_IDLE Mar 26 11:04:48 tracker-extract: Setting priority nice level to 19 Mar 26 11:04:48 dbus-daemon: [session uid=1000 pid=1311] Successfully activated service 'org.freedesktop.Tracker1.Miner.Extract' Mar 26 11:04:48 systemd: Started Tracker metadata extractor. Mar 26 11:04:51 systemd: gnome-terminal-server.service: Succeeded. Mar 26 11:04:58 systemd: tracker-extract.service: Succeeded. Mar 26 11:05:11 systemd: systemd-timedated.service: Succeeded. Mar 26 11:05:18 tracker-store: OK Mar 26 11:05:18 systemd: tracker-store.service: Succeeded. Mar 26 11:05:19 rtkit-daemon: Supervising 6 threads of 5 processes of 1 users.