# dhcp hanging?

## hanj

So I have one box running dhcpd and recently it's been doing some weird things. Primarily DHCP will hang and stop handing out IPs.  This is intermittent. Sometimes happens every hour or so.. but then can go days and be fine. Restarting dhcp fixes the problem. Nothing in /var/log/messages showing any issues. DHCP will just stop logging and giving IPs.

I thought this was related to syslog-ng acting weird as well. Syslog-ng would hang as well, and restarting would complain about unable to stop and I would need to kill the process, delete the pid and zap the service. I figured that was the DHCP problem, but dealing with this, syslog-ng seems to be working fine, and today DHCP hung while syslog-ng was working fine. 

I rolled back dhcp to previous version thinking the latest update may have had a bug, and things worked for days, until today. So the previous version of dhcp is still causing the problem (but seems less frequent).

I'm currently using dhcp-4.2.5_p1-r2 but dhcp-4.3.1-r2 was having the same issue.

Here are my USE flags:

```
[ebuild     U  ] net-misc/dhcp-4.3.1-r2::gentoo [4.2.5_p1-r2::gentoo] USE="client server ssl -ipv6 -ldap (-selinux) -vim-syntax" 8771 KiB
```

DHCP is chroot'd.

Right now I'm running dhcp in strace to see if that can tell me anything.

Here is my emerge --info output

```

Portage 2.2.18 (python 3.3.5-final-0, hardened/linux/x86, gcc-4.7.3, glibc-2.20-r2, 3.15.5-hardened-r2 i686)

=================================================================

System uname: Linux-3.15.5-hardened-r2-i686-Intel-R-_Atom-TM-_CPU_330_@_1.60GHz-with-gentoo-2.2

KiB Mem:     1022400 total,    215836 free

KiB Swap:     979960 total,    949008 free

Timestamp of repository gentoo: Fri, 01 May 2015 09:00:01 +0000

sh bash 4.2_p53

ld GNU ld (Gentoo 2.24 p1.4) 2.24

app-shells/bash:          4.2_p53::gentoo

dev-lang/perl:            5.20.2::gentoo

dev-lang/python:          2.7.9-r1::gentoo, 3.2.5-r6::gentoo, 3.3.5-r1::gentoo, 3.4.1::gentoo

dev-util/cmake:           2.8.12.2-r1::gentoo

dev-util/pkgconfig:       0.28-r2::gentoo

sys-apps/baselayout:      2.2::gentoo

sys-apps/openrc:          0.13.11::gentoo

sys-apps/sandbox:         2.6-r1::gentoo

sys-devel/autoconf:       2.69::gentoo

sys-devel/automake:       1.10.3-r1::gentoo, 1.11.6::gentoo, 1.12.6::gentoo, 1.13.4::gentoo

sys-devel/binutils:       2.24-r3::gentoo

sys-devel/gcc:            4.1.2::gentoo, 4.3.4::gentoo, 4.4.5::gentoo, 4.5.4::gentoo, 4.6.3::gentoo, 4.7.3-r1::gentoo, 4.8.4::gentoo

sys-devel/gcc-config:     1.7.3::gentoo

sys-devel/libtool:        2.4.6::gentoo

sys-devel/make:           4.1-r1::gentoo

sys-kernel/linux-headers: 3.18::gentoo (virtual/os-headers)

sys-libs/glibc:           2.20-r2::gentoo

Repositories:

gentoo

    location: /usr/portage

    sync-type: rsync

    sync-uri: rsync://rsync.gentoo.org/gentoo-portage

    priority: -1000

ACCEPT_KEYWORDS="x86"

ACCEPT_LICENSE="* -@EULA"

CBUILD="i686-pc-linux-gnu"

CFLAGS="-O3 -march=pentium4 -funroll-loops -fprefetch-loop-arrays -pipe"

CHOST="i686-pc-linux-gnu"

CONFIG_PROTECT="/etc /usr/share/gnupg/qualified.txt"

CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/env.d /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo"

CXXFLAGS="-O2 -mtune=i686 -pipe"

DISTDIR="/usr/portage/distfiles"

FCFLAGS="-march=i686 -O2 -pipe"

FEATURES="assume-digests binpkg-logs config-protect-if-modified distlocks ebuild-locks fixlafiles merge-sync news parallel-fetch preserve-libs protect-owned sandbox sfperms strict unknown-features-warn unmerge-logs unmerge-orphans userfetch userpriv usersandbox usersync xattr"

FFLAGS="-march=i686 -O2 -pipe"

GENTOO_MIRRORS="http://distfiles.gentoo.org"

LDFLAGS="-Wl,-O1 -Wl,--as-needed"

PKGDIR="/usr/portage/packages"

PORTAGE_CONFIGROOT="/"

PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --omit-dir-times --compress --force --whole-file --delete --stats --human-readable --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages"

PORTAGE_TMPDIR="/var/tmp"

USE="acl berkdb bzip2 cli cracklib crypt cxx dri gdbm hardened iconv modules mysql ncurses nls nptl nptlonly openmp pam pax_kernel pcre pic readline session ssl tcpd urandom x86 xattr xtpax zlib" ABI_X86="32" ALSA_CARDS="ali5451 als4000 atiixp atiixp-modem bt87x ca0106 cmipci emu10k1 emu10k1x ens1370 ens1371 es1938 es1968 fm801 hda-intel intel8x0 intel8x0m maestro3 trident usb-audio via82xx via82xx-modem ymfpci" APACHE2_MODULES="authn_core authz_core socache_shmcb unixd actions alias auth_basic authn_alias authn_anon authn_dbm authn_default authn_file authz_dbm authz_default authz_groupfile authz_host authz_owner authz_user autoindex cache cgi cgid dav dav_fs dav_lock deflate dir disk_cache env expires ext_filter file_cache filter headers include info log_config logio mem_cache mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias" CALLIGRA_FEATURES="kexi words flow plan sheets stage tables krita karbon braindump author" CAMERAS="ptp2" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf superstar2 timing tsip tripmate tnt ublox ubx" INPUT_DEVICES="keyboard mouse evdev" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php5-5" PYTHON_SINGLE_TARGET="python2_7" PYTHON_TARGETS="python2_7 python3_3" RUBY_TARGETS="ruby19 ruby20" USERLAND="GNU" VIDEO_CARDS="apm ark chips cirrus cyrix dummy fbdev glint i128 i740 intel mach64 mga nsc nv r128 radeon rendition s3 s3virge savage siliconmotion sis sisusb tdfx tga trident tseng v4l vesa via vmware nouveau" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq steal rawnat logmark ipmark dhcpmac delude chaos account"

Unset:  CPPFLAGS, CTARGET, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LANG, LC_ALL, MAKEOPTS, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS, USE_PYTHON
```

There is plenty of free disk on the box. I almost feel it's an issue with the lease file.. not sure. Any help is greatly appreciated.

Thanks!

hanji

----------

## hanj

Hmmm... DHCP hung again. Last entries in strace shows...

```
22917 time(NULL)                        = 1430495517

22917 send(3, "<30>May  1 15:51:57 dhcpd: DHCPI"..., 62, MSG_NOSIGNAL) = 62

22917 time(NULL)                        = 1430495517

22917 send(3, "<30>May  1 15:51:57 dhcpd: DHCPA"..., 77, MSG_NOSIGNAL
```

Which is normal

Also, syslog-ng just hung as well (at the same time). One thing I noticed. When I did a ps aux | grep dhcp, I saw 2 processes.. my strace process (which was the only one when I started) and dhcp. So something looks to have started dhcp on top of it? Likewise, doing a ps aux | grep syslog, there were 2 processes. I had to kill them both to restart syslog and dhcp.

Thoughts?

hanji

----------

