why I have lost messages on boot even with very big backlog while I hunting only 2 syscalls?

[Lev Olshvang]

28.09.2017, 00:32, "Steve Grubb" <sgrubb at redhat.com>:
> On Wednesday, September 27, 2017 4:41:29 PM EDT Lev Olshvang wrote:
>>  Hello list !
>>
>>  A very technical question
>>  I have Ubuntu 16.10 Virtual Box , auditd 2.7.8
>>  I have audit=1 parameter in grub.cfg
>>  I see that /proc/cmdline indeed sees it
>>
>>  I see that auditd is started with PID 564
>>
>>  root 312 2 0 23:12 ? 00:00:00 [kauditd]
>>  root 564 1 0 23:12 ? 00:00:00 /sbin/auditd
>>
>>  And I have 15 lost messages ???
>>  auditctl -s
>>  enabled 1
>>  failure 1
>>  pid 564
>>  rate_limit 0
>>  backlog_limit 16384
>>  lost 15
>>  backlog 0
>>  backlog_wait_time 30
>>  loginuid_immutable 0 unlocked
>>
>>  auditctl -l
>>  -a always,exit -F arch=b64 -S execve,execveat -F key=exec
>>
>>  Do I understand correctly that auiditd is indeed started by systemd before
>>  other services, except 2 that is listed in auditd.service dependencuies -
>>  local-fs and some temp setup of systemd ?
>
> Yes, it is started before most services. However. systemd-journal for some
> reason feels obligated to enable auditing. And sometimes people put audit=1 on
> the kernel command line. Either way, auditing is on way before auditd starts.
> The audit logs have a 64 entry buffer by default. So, as the system boots
> events pile up and eventually overflows the 64 entry limit.
>
> The fix is to add another boot command option audit_backlog_limit=8192 or some
> other suitable number. The test to check for this is to boot your system,
> login and run auditctl -s. If you have just booted and lost events during
> boot, this should fix it.
>
> -Steve

Hi Steve

Thank you for your answer.
I added backlog parameter  as you advised, but it did not solve the problem


cat /proc/cmdline 
BOOT_IMAGE=/vmlinuz-4.8.0-59-generic root=/dev/mapper/kubuntu--vg-root ro net.ifnames=0 biosdevname=0 audit=1 audit_backlog_limit=8192 debug splash
auditctl -s
enabled 1
failure 1
pid 672
rate_limit 0
backlog_limit 16384
lost 16
backlog 10
backlog_wait_time 30
loginuid_immutable 0 unlocked

Perhaps something else in configuration ?
Ragards,
Lev