Arch Linux

Kardell

Member

From: London a new Babylon

Registered: 2007-02-20

Posts: 228

Logs overflooding

1,6GB of logs (kernel.log, everything.log, ...) generated in one hour until low memory and finally kernel panic.
My firewall was made by some online generator.
Can I change the log level for iptables?

Apr  5 16:57:33 skywalker ipt# bledne_pakiety IN=eth0 OUT= MAC=00:e0:4c:e9:c6:d6:00:15:f9:64:1a:c1:08:00 SRC=128.142.160.33 DST=156.17.234.114 LEN=52 TOS=0x00 PREC=0x0
0 TTL=44 ID=44307 DF PROTO=TCP SPT=80 DPT=34172 WINDOW=1888 RES=0x00 ACK RST URGP=0
Apr  5 16:57:34 skywalker ipt# bledne_pakiety IN=eth0 OUT= MAC=00:e0:4c:e9:c6:d6:00:15:f9:64:1a:c1:08:00 SRC=163.1.242.50 DST=156.17.234.114 LEN=52 TOS=0x00 PREC=0x00
TTL=36 ID=35758 DF PROTO=TCP SPT=80 DPT=54445 WINDOW=2184 RES=0x00 ACK RST URGP=0
Apr  5 16:58:02 skywalker ipt# bledne_pakiety IN=eth0 OUT= MAC=00:e0:4c:e9:c6:d6:00:15:f9:64:1a:c1:08:00 SRC=128.142.160.33 DST=156.17.234.114 LEN=52 TOS=0x00 PREC=0x0
0 TTL=44 ID=44308 DF PROTO=TCP SPT=80 DPT=34172 WINDOW=1888 RES=0x00 ACK RST URGP=0
Apr  5 16:58:04 skywalker ipt# bledne_pakiety IN=eth0 OUT= MAC=00:e0:4c:e9:c6:d6:00:15:f9:64:1a:c1:08:00 SRC=163.1.242.50 DST=156.17.234.114 LEN=52 TOS=0x00 PREC=0x00
TTL=36 ID=35759 DF PROTO=TCP SPT=80 DPT=54445 WINDOW=2184 RES=0x00 ACK RST URGP=0
Apr  5 17:02:04 skywalker syslog-ng[4032]: Log statistics; processed='center(queued)=2862', processed='center(received)=981', processed='destination(console)=0', proce
ssed='destination(mail)=0', processed='destination(user)=0', processed='destination(uucp)=0', processed='destination(messages)=301', processed='destination(news)=0', p
rocessed='destination(iptables)=579', processed='destination(everything)=978', processed='destination(lpr)=0', processed='destination(cron)=0', processed='destination(
syslog)=32', processed='destination(authlog)=3', processed='destination(errors)=23', processed='destination(kernel)=946', processed='destination(daemon)=0', processed=
'source(src)=981'
Apr  5 17:02:56 skywalker ipt# INPUT:99 IN=eth0 OUT= MAC=00:e0:4c:e9:c6:d6:00:15:f9:64:1a:c1:08:00 SRC=153.107.41.159 DST=156.17.234.114 LEN=512 TOS=0x00 PREC=0x00 TTL
=48 ID=65027 PROTO=UDP SPT=30936 DPT=1026 LEN=492
Apr  5 17:05:57 skywalker ipt# INPUT:99 IN=eth0 OUT= MAC=00:e0:4c:e9:c6:d6:00:15:f9:64:1a:c1:08:00 SRC=156.17.162.177 DST=156.17.234.114 LEN=64 TOS=0x00 PREC=0x00 TTL=
43 ID=31662 DF PROTO=TCP SPT=3920 DPT=5800 WINDOW=53760 RES=0x00 SYN URGP=0
Apr  5 17:06:01 skywalker ipt# INPUT:99 IN=eth0 OUT= MAC=00:e0:4c:e9:c6:d6:00:15:f9:64:1a:c1:08:00 SRC=156.17.162.177 DST=156.17.234.114 LEN=64 TOS=0x00 PREC=0x00 TTL=
43 ID=33162 DF PROTO=TCP SPT=1557 DPT=1433 WINDOW=53760 RES=0x00 SYN URGP=0
Apr  5 17:06:56 skywalker ipt# INPUT:99 IN=eth0 OUT= MAC=00:e0:4c:e9:c6:d6:00:15:f9:64:1a:c1:08:00 SRC=75.4.174.64 DST=156.17.234.114 LEN=126 TOS=0x00 PREC=0x00 TTL=11
3 ID=16149 PROTO=UDP SPT=24253 DPT=14826 LEN=106
Apr  5 17:08:41 skywalker active!
Apr  5 17:08:41 skywalker release_dev: ptm0: read/write wait queue active!
Apr  5 17:08:41 skywalker release_dev: ptm0: read/write wait queue active!
Apr  5 17:08:41 skywalker release_dev: ptm0: read/write wait queue active!
Apr  5 17:08:41 skywalker release_dev: ptm0: read/write wait queue active!
Apr  5 17:08:41 skywalker release_dev: ptm0: read/write wait queue active!
Apr  5 17:08:41 skywalker release_dev: ptm0: read/write wait queue active!
Apr  5 17:08:41 skywalker release_dev: ptm0: read/write wait queue active!
.
.
10km :-o
.
.
Apr  5 18:03:30 skywalker release_dev: ptm0: read/write wait queue active!
Apr  5 18:03:30 skywalker release_dev: ptm0: read/write wait queue active!
Apr  5 18:03:30 skywalker release_dev: ptm0: read/write wait queue active!

Last edited by Kardell (2007-05-20 20:28:11)

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"Those who don't know history are doomed to repeat it." Edmund Burke

liem

Member

Registered: 2006-04-29

Posts: 71

Website

Re: Logs overflooding

Post the iptables rules?

What do you wanna accomplice?

---

Sebastian  A. Liem

jerem

Member

From: France

Registered: 2005-01-15

Posts: 310

Re: Logs overflooding

You might want to only log connection attemps, by matching only the SYN flag(ACK being unarmed), which should heavily reduce what is logged.

You can also fine tune logrotate to rotate every half hour...

Kardell

Member

From: London a new Babylon

Registered: 2007-02-20

Posts: 228

Re: Logs overflooding

You might want to only log connection attemps, by matching only the SYN flag(ACK being unarmed), which should heavily reduce what is logged.

You can also fine tune logrotate to rotate every half hour...

Thx ;-)

firewall.sh from /etc/iptables/

#!/bin/sh

################
# Konfiguracja #
################

F="/usr/sbin/iptables"
LOG="ipt#"

#interfejs globalny - dla sieci zewnetrznej
G_NET_NAME="eth0"
G_NET_IP="<censored>"

#ustawienie modulow i konfiguracji jadra
/usr/sbin/modprobe ip_tables
/usr/sbin/modprobe ip_conntrack
/usr/sbin/modprobe ip_nat_ftp
/usr/sbin/modprobe ip_conntrack_ftp

echo "1" > /proc/sys/net/ipv4/ip_forward

#dynamiczny przydzial adresu
#echo "1" > /proc/sys/net/ipv4/ip_dynaddr

#ignorowanie ICMP echo request wysylanych na adres rozgloszeniowy
echo "1" > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts

#ochrona przed SYN flood
echo "1" > /proc/sys/net/ipv4/tcp_syncookies

#refuse source routed packets
echo "0" > /proc/sys/net/ipv4/conf/all/accept_source_route

echo "1" > /proc/sys/net/ipv4/conf/all/secure_redirects

#walidacja zrodla za pomoca reversed path (RFC1812).
echo "1" > /proc/sys/net/ipv4/conf/all/rp_filter

#logowanie pakietow z nieprawidlowych adresow
echo "1" > /proc/sys/net/ipv4/conf/all/log_martians

#################
# INICJALIZACJA #
#################

echo "Ustawienia polityki dla lancuchow standardowych..."
$F -P INPUT ACCEPT
$F -P FORWARD ACCEPT
$F -P OUTPUT ACCEPT
$F -t nat -P PREROUTING ACCEPT
$F -t nat -P OUTPUT ACCEPT
$F -t nat -P POSTROUTING ACCEPT
$F -t mangle -P PREROUTING ACCEPT
$F -t mangle -P OUTPUT ACCEPT
$F -t mangle -P INPUT ACCEPT
$F -t mangle -P FORWARD ACCEPT
$F -t mangle -P POSTROUTING ACCEPT

echo "Czyszczenie regul dla lancuchow standardowych..."
$F -F
$F -t nat -F
$F -t mangle -F

echo "Kasowanie wszystkich niestandardowych lancuchow..."
$F -X
$F -t nat -X
$F -t mangle -X

if [ "$1" = "stop" ]
then
    echo "Firewall zostal wylaczony."
    exit 0
fi

echo "Ustawienia polityki lancuchow standardowych..."
$F -P INPUT DROP
$F -P OUTPUT DROP
$F -P FORWARD DROP

echo "Tworzenie niestandardowych lancuchow regul..."
$F -N bledne_pakiety
$F -N bledne_pakiety_tcp
$F -N pakiety_icmp
$F -N tcp_wchodzace
$F -N tcp_wychodzace
$F -N udp_wchodzace
$F -N udp_wychodzace

##################
# bledne_pakiety #
##################
echo "Tworzenie regul dla lancucha bledne_pakiety..."

$F -A bledne_pakiety -p ALL -m state --state INVALID -j LOG --log-prefix "$LOG bledne_pakiety "
$F -A bledne_pakiety -p ALL -m state --state INVALID -j DROP
$F -A bledne_pakiety -p tcp -j bledne_pakiety_tcp
$F -A bledne_pakiety -p ALL -j RETURN

######################
# bledne_pakiety_tcp #
######################
echo "Tworzenie regul dla lancucha bledne_pakiety_tcp..."
#dla gate
$F -A bledne_pakiety_tcp -p tcp -i $L_NET_NAME -j RETURN

$F -A bledne_pakiety_tcp -p tcp ! --syn -m state --state NEW -j LOG --log-prefix "$LOG bledne_pakiety_tcp "
$F -A bledne_pakiety_tcp -p tcp ! --syn -m state --state NEW -j DROP

$F -A bledne_pakiety_tcp -p tcp --tcp-flags ALL NONE -j LOG --log-prefix "$LOG bledne_pakiety_tcp "
$F -A bledne_pakiety_tcp -p tcp --tcp-flags ALL NONE -j DROP

$F -A bledne_pakiety_tcp -p tcp --tcp-flags ALL ALL -j LOG --log-prefix "$LOG bledne_pakiety_tcp "
$F -A bledne_pakiety_tcp -p tcp --tcp-flags ALL ALL -j DROP

$F -A bledne_pakiety_tcp -p tcp --tcp-flags ALL FIN,URG,PSH -j LOG --log-prefix "$LOG bledne_pakiety_tcp "
$F -A bledne_pakiety_tcp -p tcp --tcp-flags ALL FIN,URG,PSH -j DROP

$F -A bledne_pakiety_tcp -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j LOG --log-prefix "$LOG bledne_pakiety_tcp "
$F -A bledne_pakiety_tcp -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j DROP

$F -A bledne_pakiety_tcp -p tcp --tcp-flags SYN,RST SYN,RST -j LOG --log-prefix "$LOG bledne_pakiety_tcp "
$F -A bledne_pakiety_tcp -p tcp --tcp-flags SYN,RST SYN,RST -j DROP

$F -A bledne_pakiety_tcp -p tcp --tcp-flags SYN,FIN SYN,FIN -j LOG --log-prefix "$LOG bledne_pakiety_tcp "
$F -A bledne_pakiety_tcp -p tcp --tcp-flags SYN,FIN SYN,FIN -j DROP

$F -A bledne_pakiety_tcp -p tcp -j RETURN

################
# pakiety_icmp #
################
echo "Tworzenie regul dla lancucha pakiety_icmp..."

$F -A pakiety_icmp --fragment -p ICMP -j LOG --log-prefix "$LOG pakiety_icmp fragmenty "
$F -A pakiety_icmp --fragment -p ICMP -j DROP

#pingowanie i logowanie pingowania
# $F -A pakiety_icmp -p ICMP -s 0/0 --icmp-type 8 -j LOG --log-prefix "$LOG pakiety_icmp "
# $F -A pakiety_icmp -p ICMP -s 0/0 --icmp-type 8 -j ACCEPT

#ping - zachaszowac w przypadku odsloniecia powyzszych regul
$F -A pakiety_icmp -p ICMP -s 0/0 --icmp-type 8 -j DROP
#Time Exceeded
$F -A pakiety_icmp -p ICMP -s 0/0 --icmp-type 11 -j ACCEPT

$F -A pakiety_icmp -p ICMP -j RETURN

#################
# tcp_wchodzace #
#################
echo "Tworzenie regul dla lancucha tcp_wchodzace..."

#ident request
#reject zamiast drop w celu unikniecia opoznien przy polaczeniach
$F -A tcp_wchodzace -p TCP -s 0/0 --destination-port 113 -j REJECT
#FTP client (data port non-PASV)
$F -A tcp_wchodzace -p TCP -s 0/0 --source-port 20 -j ACCEPT
#FTP control
$F -A tcp_wchodzace -p TCP -s 0/0 --destination-port 21 -j ACCEPT
# Passive FTP
$F -A tcp_wchodzace -p TCP -s 0/0 --destination-port 62000:64000 -j ACCEPT
#ssh
$F -A tcp_wchodzace -p TCP -s 0/0 --destination-port 22 -j ACCEPT
#HTTP
$F -A tcp_wchodzace -p TCP -s 0/0 --destination-port 80 -j ACCEPT
#HTTPS
$F -A tcp_wchodzace -p TCP -s 0/0 --destination-port 443 -j ACCEPT
#SMTP
$F -A tcp_wchodzace -p TCP -s 0/0 --destination-port 25 -j ACCEPT
#POP3
$F -A tcp_wchodzace -p TCP -s 0/0 --destination-port 110 -j ACCEPT
#SSL POP3
$F -A tcp_wchodzace -p TCP -s 0/0 --destination-port 995 -j ACCEPT
#IMAP4
$F -A tcp_wchodzace -p TCP -s 0/0 --destination-port 143 -j ACCEPT
#SSL IMAP4
$F -A tcp_wchodzace -p TCP -s 0/0 --destination-port 993 -j ACCEPT
#ICQ File Transfers & Other Advanced Features
#$F -A tcp_wchodzace -p TCP -s 0/0 --destination-port : -j ACCEPT
$F -A tcp_wchodzace -p TCP -s 0/0 --destination-port 119 -j ACCEPT
#User specified allowed TCP protocol
$F -A tcp_wchodzace -p TCP -s 0/0 --destination-port 4662 -j ACCEPT

#nie pasujace: powrot i logowanie
$F -A tcp_wchodzace -p TCP -j RETURN

##################
# tcp_wychodzace #
##################
echo "Tworzenie regul dla lancucha tcp_wychodzace..."

#nie pasujace ACCEPT
$F -A tcp_wychodzace -p TCP -s 0/0 -j ACCEPT

#################
# udp_wchodzace #
#################
echo "Tworzenie regul dla lancucha udp_wchodzace..."

#Drop netbios calls
$F -A udp_wchodzace -p UDP -s 0/0 --destination-port 137 -j DROP
$F -A udp_wchodzace -p UDP -s 0/0 --destination-port 138 -j DROP

#ident - reject zamiast drop w celu unikniecia opoznien w polaczeniach
$F -A udp_wchodzace -p UDP -s 0/0 --destination-port 113 -j REJECT


#DNS
$F -A udp_wchodzace -p UDP -s 0/0 --destination-port 53 -j ACCEPT
#dopuszczalny zakres portow udp
$F -A udp_wchodzace -p UDP -s 0/0 --destination-port 4672 -j ACCEPT

#nie pasujace - powrot i logowanie
$F -A udp_wchodzace -p UDP -j RETURN

##################
# udp_wychodzace #
##################
echo "Tworzenie regul dla lancucha udp_wychodzace..."

#nie pasujace ACCEPT
$F -A udp_wychodzace -p UDP -s 0/0 -j ACCEPT

#########
# INPUT #
#########

echo "Tworzenie regul dla lancucha INPUT..."

$F -A INPUT -p ALL -i lo -j ACCEPT
$F -A INPUT -p ALL -j bledne_pakiety

#DOCSIS compliant cable modems
#Drop without logging.
$F -A INPUT -p ALL -d 224.0.0.1 -j DROP

#Ustanowione polaczenia
$F -A INPUT -p ALL -i $G_NET_NAME -m state --state ESTABLISHED,RELATED -j ACCEPT

#reszta do odpowiednich lancuchow
$F -A INPUT -p ICMP -i $G_NET_NAME -j pakiety_icmp
$F -A INPUT -p TCP -i $G_NET_NAME -j tcp_wchodzace
$F -A INPUT -p UDP -i $G_NET_NAME -j udp_wchodzace

#zatrzymanie rozgloszen
$F -A INPUT -p ALL -d 255.255.255.255 -j DROP

#nie pasujace - logowanie
$F -A INPUT -j LOG --log-prefix "$LOG INPUT:99 "

###########
# FORWARD #
###########
#dla gate caly
echo "Tworzenie regul dla lancucha FORWARD..."

#nie pasujace - loguj
$F -A FORWARD -j LOG --log-prefix "$LOG FORWARD:99 "

##########
# OUTPUT #
##########

echo "Tworzenie regul dla lancucha OUTPUT..."

$F -A OUTPUT -m state -p icmp --state INVALID -j DROP
$F -A OUTPUT -p ALL -s 127.0.0.1 -j ACCEPT
$F -A OUTPUT -p ALL -o lo -j ACCEPT

$F -A OUTPUT -p ALL -o $G_NET_NAME -j ACCEPT

#nie pasujace - loguj
$F -A OUTPUT -j LOG --log-prefix "$LOG OUTPUT:99 "

################
# mangle table #
################
echo "Tworzenie regul dla mangle table..."

Last edited by Kardell (2007-04-12 00:19:25)

---

"Those who don't know history are doomed to repeat it." Edmund Burke

Kardell

Member

From: London a new Babylon

Registered: 2007-02-20

Posts: 228

Re: Logs overflooding

I found some similar problem investigation:

release_dev: tty10: read/write wait queue active!

Looking at tty_io.c (where the message originates) it appears that the tty
code is waiting for some queue (probably the write queue) to drain before
it finishes the close.  The code also loops forever here printk'ing the
message (to the console and syslogd) then calling schedule() until the
condition is cleared. 

The problem (I assume) is that the condition is not clearing so your
machine gets consumed endlessly printing the message. The message should
have been programmed to print only once.  It probably should call sleep
instead of schedule() but if this code gets run at interrupt it would be
very bad to call sleep.

There has always been a problem with what to do on a serial port closing
with data that has not drained.  If it's a pty

You have two choices:

1) Modify the tty_io.c code and have it exit the loop after a while and/or
only print the message once.

2) Take action on your tty link to prevent this deadlock.  I would guess
you are using hardware handshaking and closing the port before the fifo
has emptied.  If you can wait in the app before closing.

Doug, thanks for the ideas!  I played with stty a bit and then tried sync and init 0.  I was able to get the machine shutdown and restarted with syslogd not configured to output to /dev/tty10.  To my surprise, I was still getting messages on tty10!  I searched thru the startup scripts and found that in boot.klog there is a section that uses the /usr/sbin/klogconsole to direct the kernel to send printk messages to /dev/tty10.  So, I'll watch the machine and see if syslog hangs, klog hangs, or nothing.   

How do I find out if it is a pty or a tty?  I have thought that a pty is virtual terminal and a tty was a real serial port.  What is confusing is that the output is seen on virtual terminal 10 by switching with Alt-F10.  So does that mean that it is a pty assigned to a virtual terminal?  Is the /dev/tty10 actual treated as a pty by the kernel since the hardware for a real serial port isn't there in this machine?  How do you track these assignments?  Can you find them in /proc?

What do you think about it?

---

"Those who don't know history are doomed to repeat it." Edmund Burke

Kardell

Member

From: London a new Babylon

Registered: 2007-02-20

Posts: 228

Re: Logs overflooding

May 23 23:01:13 skywalker Stack: d759bf58 d759bf40 d759bf40 dae58800 00000400 00000400 c0276d13 00000001
May 23 23:01:13 skywalker dae58c14 dae58950 dae58bcc bfa92407 d2893700 00000001 00000000 00000000
May 23 23:01:13 skywalker 7fffffff 00000000 dcf66550 c0123100 dae58958 dae58958 bfa92807 d2893700
May 23 23:01:13 skywalker Call Trace:
May 23 23:01:13 skywalker [<c0276d13>] read_chan+0x3b3/0x610
May 23 23:01:13 skywalker [<c0123100>] default_wake_function+0x0/0x10
May 23 23:01:13 skywalker [<c027368d>] tty_read+0x8d/0xd0
May 23 23:01:13 skywalker [<c0276960>] read_chan+0x0/0x610
May 23 23:01:13 skywalker [<c017597c>] vfs_read+0xbc/0x160
May 23 23:01:13 skywalker [<c0273600>] tty_read+0x0/0xd0
May 23 23:01:13 skywalker [<c0175eb1>] sys_read+0x41/0x70
May 23 23:01:13 skywalker [<c0104232>] sysenter_past_esp+0x5f/0x85
May 23 23:01:13 skywalker =======================
May 23 23:01:13 skywalker Code: 0c 00 89 da 03 96 b8 01 00 00 29 9e bc 01 00 00 81 e2 ff 0f 00 00 89 96 b8 01 00 00 89 c2 89 f8 e8 dc df 0c 00 8b 44 24 04 01 18 <8b> 0
4 24 29 18 89 e8 8b 5c 24 08 8b 74 24 0c 8b 7c 24 10 8b 6c
May 23 23:01:13 skywalker EIP: [<c02753da>] copy_from_read_buf+0xaa/0xd0 SS:ESP 0068:d759bee8
May 23 23:01:13 skywalker active!
May 23 23:01:13 skywalker release_dev: ptm0: read/write wait queue active!
May 23 23:01:13 skywalker release_dev: ptm0: read/write wait queue active!
May 23 23:01:13 skywalker release_dev: ptm0: read/write wait queue active!

May 24 01:00:03 skywalker postfix/postdrop[9488]: warning: unable to look up public/pickup: No such file or directory
May 24 01:00:17 skywalker ipt# bledne_pakiety IN=eth0 OUT= MAC=00:e0:4c:e9:c6:d6:00:15:f9:64:1a:c1:08:00 SRC=87.117.229.205 DST=156.17.234.114 LEN=40 TOS=0x00 PREC=0x0
0 TTL=51 ID=0 DF PROTO=TCP SPT=80 DPT=56400 WINDOW=0 RES=0x00 RST URGP=0
May 24 01:00:26 skywalker ipt# INPUT:99 IN=eth0 OUT= MAC=ff:ff:ff:ff:ff:ff:00:80:5f:77:9a:fd:08:00 SRC=156.17.235.54 DST=156.17.235.255 LEN=213 TOS=0x00 PREC=0x00 TTL=
64 ID=0 DF PROTO=UDP SPT=631 DPT=631 LEN=193
May 24 01:00:57 skywalker ipt# INPUT:99 IN=eth0 OUT= MAC=ff:ff:ff:ff:ff:ff:00:80:5f:77:9a:fd:08:00 SRC=156.17.235.54 DST=156.17.235.255 LEN=213 TOS=0x00 PREC=0x00 TTL=
64 ID=0 DF PROTO=UDP SPT=631 DPT=631 LEN=193
May 24 01:01:00 skywalker fcron[9492]: Job /usr/sbin/run-cron /etc/cron.hourly started for user systab (pid 9493)
May 24 01:01:00 skywalker fcron[9494]: Job cd /home/httpd/html/psw/;svn update started for user root (pid 9495)
May 24 01:01:00 skywalker fcron[9497]: Job cd /home/httpd/html/beta/;svn update started for user root (pid 9498)
May 24 01:01:02 skywalker fcron[9492]: Job /usr/sbin/run-cron /etc/cron.hourly completed
May 24 01:01:03 skywalker fcron[9494]: Job cd /home/httpd/html/psw/;svn update completed (mailing output)
May 24 01:01:03 skywalker fcron[9497]: Job cd /home/httpd/html/beta/;svn update completed (mailing output)
May 24 01:01:03 skywalker postfix/postdrop[9501]: warning: unable to look up public/pickup: No such file or directory
May 24 01:01:03 skywalker postfix/postdrop[9500]: warning: unable to look up public/pickup: No such file or directory
May 24 01:01:28 skywalker ipt# INPUT:99 IN=eth0 OUT= MAC=ff:ff:ff:ff:ff:ff:00:80:5f:77:9a:fd:08:00 SRC=156.17.235.54 DST=156.17.235.255 LEN=213 TOS=0x00 PREC=0x00 TTL=
64 ID=0 DF PROTO=UDP SPT=631 DPT=631 LEN=193
May 24 01:02:00 skywalker active!
May 24 01:02:00 skywalker release_dev: ptm0: read/write wait queue active!
May 24 01:02:00 skywalker release_dev: ptm0: read/write wait queue active!

We think that`s conflict between kernel and some hazardous graphic card module, which produces these neverending loop error.

---

"Those who don't know history are doomed to repeat it." Edmund Burke