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Tim He avatar Ubuntu

Why the system unexpectedly reboot with ^@ in log

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Tim He

When reboot happens (last reboot)

The system reboot at Jun 19, 13:14:

reboot   system boot  5.8.0-55-generic Sat Jun 19 13:41   still running

What does the /var/log/kern.log say

There are many strange ^@ in the log.

Jun 19 11:04:53 timhe-NF5270M3 kernel: [ 6372.466957] sysctl (96257): drop_caches: 3
Jun 19 11:05:29 timhe-NF5270M3 kernel: [ 6407.535539] sysctl (96466): drop_caches: 3
Jun 19 11:05:40 timhe-NF5270M3 kernel: [ 6418.735800] sysctl (96611): drop_caches: 3
... (many same drop_caches here) ...
Jun 19 13:39:41 timhe-NF5270M3 kernel: [15660.335747] sysctl (121489): drop_caches: 3
^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000] Linux version 5.8.0-55-generic (buildd@lgw01-amd64-035) (gcc (Ubuntu 10.2.0-13ubuntu1) 10.2.0, GNU ld (GNU Binutils for Ubuntu) 2.35.1) #62-Ubuntu SMP Tue Jun 1 08:21:18 UTC 2021 (Ubuntu 5.8.0-55.62-generic 5.8.18)
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-5.8.0-55-generic root=UUID=49b55adc-d909-470d-8a6b-87401c8ae63d ro quiet splash vt.handoff=7
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000] KERNEL supported cpus:
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000]   Intel GenuineIntel
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000]   AMD AuthenticAMD
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000]   Hygon HygonGenuine
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000]   Centaur CentaurHauls
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000]   zhaoxin   Shanghai
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000] x86/fpu: Supporting XSAVE feature 0x001: 'x87 floating point registers'
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000] x86/fpu: Supporting XSAVE feature 0x002: 'SSE registers'
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000] x86/fpu: Supporting XSAVE feature 0x004: 'AVX registers'
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000] x86/fpu: xstate_offset[2]:  576, xstate_sizes[2]:  256
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000] x86/fpu: Enabled xstate features 0x7, context size is 832 bytes, using 'compacted' format.
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000] BIOS-provided physical RAM map:

What does the /var/log/syslog say

There are many strange ^@ in the log ALSO. These SSL-related ERRORs are not likely the case. Because there are many in the syslog but without any reboot.

Jun 19 13:38:26 timhe-NF5270M3 kernel: [15584.398190] sysctl (121245): drop_caches: 3
Jun 19 13:38:32 timhe-NF5270M3 gnome-shell[6286]: [6319:6322:0619/133832.745132:ERROR:ssl_client_socket_impl.cc(924)] handshake failed; returned -1, SSL error code 1, net_error -100
Jun 19 13:38:33 timhe-NF5270M3 gnome-shell[6286]: [6319:6322:0619/133833.563490:ERROR:ssl_client_socket_impl.cc(924)] handshake failed; returned -1, SSL error code 1, net_error -100
Jun 19 13:38:37 timhe-NF5270M3 gnome-shell[6286]: [6319:6322:0619/133837.045183:ERROR:ssl_client_socket_impl.cc(924)] handshake failed; returned -1, SSL error code 1, net_error -100
Jun 19 13:38:43 timhe-NF5270M3 gnome-shell[6286]: [6319:6322:0619/133843.701016:ERROR:ssl_client_socket_impl.cc(924)] handshake failed; returned -1, SSL error code 1, net_error -100
Jun 19 13:38:47 timhe-NF5270M3 gnome-shell[6286]: [6319:6322:0619/133847.284935:ERROR:ssl_client_socket_impl.cc(924)] handshake failed; returned -1, SSL error code 1, net_error -100
Jun 19 13:38:47 timhe-NF5270M3 gnome-shell[6286]: [6278:120888:0619/133847.285407:ERROR:get_updates_processor.cc(257)] PostClientToServerMessage() failed during GetUpdates with error 2
Jun 19 13:38:57 timhe-NF5270M3 gnome-shell[6286]: [6319:6322:0619/133857.525098:ERROR:ssl_client_socket_impl.cc(924)] handshake failed; returned -1, SSL error code 1, net_error -100
Jun 19 13:39:01 timhe-NF5270M3 CRON[121357]: (root) CMD (  [ -x /usr/lib/php/sessionclean ] && if [ ! -d /run/systemd/system ]; then /usr/lib/php/sessionclean; fi)
Jun 19 13:39:04 timhe-NF5270M3 systemd[1]: Starting Clean php session files...
Jun 19 13:39:04 timhe-NF5270M3 systemd[1]: phpsessionclean.service: Succeeded.
Jun 19 13:39:04 timhe-NF5270M3 systemd[1]: Finished Clean php session files.
Jun 19 13:39:07 timhe-NF5270M3 gnome-shell[6286]: [6319:6322:0619/133907.765231:ERROR:ssl_client_socket_impl.cc(924)] handshake failed; returned -1, SSL error code 1, net_error -100
Jun 19 13:39:41 timhe-NF5270M3 kernel: [15660.335747] sysctl (121489): drop_caches: 3
Jun 19 13:40:01 timhe-NF5270M3 CRON[121561]: (www-data) CMD (php /usr/share/cacti/site/poller.php 2>&1 >/dev/null | if [ -f /usr/bin/ts ] ; then ts ; else tee ; fi >> /var/log/cacti/poller-error.log)
Jun 19 13:40:01 timhe-NF5270M3 CRON[121560]: (CRON) info (No MTA installed, discarding output)
^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@Jun 19 13:41:43 timhe-NF5270M3 systemd-modules-load[505]: Inserted module 'lp'
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000] Linux version 5.8.0-55-generic (buildd@lgw01-amd64-035) (gcc (Ubuntu 10.2.0-13ubuntu1) 10.2.0, GNU ld (GNU Binutils for Ubuntu) 2.35.1) #62-Ubuntu SMP Tue Jun 1 08:21:18 UTC 2021 (Ubuntu 5.8.0-55.62-generic 5.8.18)
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-5.8.0-55-generic root=UUID=49b55adc-d909-470d-8a6b-87401c8ae63d ro quiet splash vt.handoff=7
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000] KERNEL supported cpus:
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000]   Intel GenuineIntel
Jun 19 13:41:43 timhe-NF5270M3 systemd-modules-load[505]: Inserted module 'ppdev'
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000]   AMD AuthenticAMD
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000]   Hygon HygonGenuine
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000]   Centaur CentaurHauls
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000]   zhaoxin   Shanghai
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000] x86/fpu: Supporting XSAVE feature 0x001: 'x87 floating point registers'
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000] x86/fpu: Supporting XSAVE feature 0x002: 'SSE registers'
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000] x86/fpu: Supporting XSAVE feature 0x004: 'AVX registers'
Jun 19 13:41:43 timhe-NF5270M3 kernel: [    0.000000] x86/fpu: xstate_offset[2]:  576, xstate_sizes[2]:  256

What am I running when it reboots

A testing script for PostgreSQL.
It start/shutdown PostgreSQL periodically via pg_ctl -D /mnt/${Device}/pgsql-data,
run workload using ./tpch.sh output-dir tpch-db postgres-user (source here),
cleanup cache between runs via echo "123" | sudo -S /sbin/sysctl vm.drop_caches=3 and echo "3" > /proc/sys/vm/drop_caches and echo "123" | sudo -S fstrim -v /mnt/${Device},
and kill some unexpected PostgreSQL processes via kill -9.

Other info

  1. The temperature of the room where the machine is placed is low (~23℃)
  2. The same unexpected reboot happens as well in my ubuntu-18.04 (same workload running)
  3. Auto-reboot is off: Unattended-Upgrade::Automatic-Reboot "true".
  4. cat /proc/sys/kernel/panic is 0.
  5. I have many block devices mounted:
➜  run git:(master) ✗ df -h
tmpfs           6.3G  2.5M  6.3G    1% /run
/dev/sdd3       110G   76G   28G   73% /
tmpfs            32G  159M   32G    1% /dev/shm
tmpfs           5.0M  4.0K  5.0M    1% /run/lock
tmpfs           4.0M     0  4.0M    0% /sys/fs/cgroup
/dev/nvme2n1    343G  228G   98G   70% /mnt/nvme-optane
/dev/sdc        440G  206G  212G   50% /mnt/sata-s4510
/dev/sdd2       512M  7.9M  505M    2% /boot/efi
/dev/sde1       1.8T  170G  1.6T   10% /mnt/hdd-smr-sg
/dev/sdb1       458G  202G  233G   47% /mnt/sata-860evo
/dev/nvme1n1p1  458G  247G  188G   57% /mnt/nvme-sn850
/dev/sda1       550G  227G  295G   44% /mnt/hdd-sas-dell
tmpfs           6.3G  188K  6.3G    1% /run/user/1000

My consideration

It is possible this is because I drop the cache too often or fstrim too often?

Thanks!

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B.Tanner avatar
bw flag
B.Tanner
^@ is likely a null character, ie 0. But I'm not sure that knowledge helps, sorry.
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nobody avatar
gh flag
nobody
Please check your harddrive with smartnontools.
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