dhcpclient and dhcpd do not stop on sigterm

[Pavel Zhukov]

Hello,
This change may be relevant:
https://github.com/mirroring/dhcp/commit/0985d149c60754feb41b34221f292de60d1ee80b

prashantkumar dhotre <prashantkumardhotre at gmail.com> writes:

> Hi experts
>
> I am using dhcpclient and dhcpd 4.3.4
>
> I am testing reboot time in my system.
> I do not have much knowledge about dhcpclient and dhcpd apps.
>
> I see that dhcpclient and dhcpd do not stop on sigterm signal.
>
> when systemd starts system shutdown, it send sigterm to all apps including dhcpclient and dhcpd.i see that these two apps do not stop.
>
> after 90 sec systemd sends sigkill and then these apps gets killed.
>
> Is this a bug in 4.3.4 version ?
>
> is this fixed in latest version ?
>
> if not, what is the work-around for this issue ?
>
> strace and systemd service files are below
>
> Thanks for you help
>
> Regards
>
> strace: 
>
> root at re:~# /usr/bin/strace -ttT -s 100 -ff -p `pidof dhclient`
>
> /usr/bin/strace: Process 21228 attached
>
> 02:29:42.167613 futex(0x7ff92089c0cc, FUTEX_WAIT_PRIVATE, 0, NULL) = ? ERESTARTSYS (To be restarted if SA_RESTART is set) <20.048539>
>
> 02:30:02.216314 --- SIGCONT {si_signo=SIGCONT, si_code=SI_USER, si_pid=1, si_uid=0} ---
>
> 02:30:02.216460 futex(0x7ff92089c0cc, FUTEX_WAIT_PRIVATE, 0, NULL <unfinished ...>
>
> 02:31:32.310754 +++ killed by SIGKILL +++
>
> root at re:~#
>
>  
>
> ++++
>
> root at evo-ptx-h-re1:~# /usr/bin/strace -ttT -s 100 -ff -p `pidof dhcpd`
>
> /usr/bin/strace: Process 22040 attached with 4 threads
>
> [pid 22046] 02:52:57.774430 futex(0x7f54707a40a0, FUTEX_WAIT_PRIVATE, 0, NULL <unfinished ...>
>
> [pid 22045] 02:52:57.774547 epoll_wait(5,  <unfinished ...>
>
> [pid 22044] 02:52:57.774560 futex(0x7f54707a10c8, FUTEX_WAIT_PRIVATE, 0, NULL <unfinished ...>
>
> [pid 22040] 02:52:57.774570 futex(0x7f54707a00e0, FUTEX_WAIT_PRIVATE, 0, NULL <unfinished ...>
>
> [pid 22046] 02:53:03.351769 <... futex resumed> ) = ? ERESTARTSYS (To be restarted if SA_RESTART is set) <5.577214>
>
> [pid 22045] 02:53:03.351792 <... epoll_wait resumed> 0x7f54707a3010, 64, -1) = -1 EINTR (Interrupted system call) <5.577239>
>
> [pid 22044] 02:53:03.351952 <... futex resumed> ) = ? ERESTARTSYS (To be restarted if SA_RESTART is set) <5.577387>
>
> [pid 22046] 02:53:03.351972 --- SIGCONT {si_signo=SIGCONT, si_code=SI_USER, si_pid=1, si_uid=0} ---
>
> [pid 22040] 02:53:03.351992 <... futex resumed> ) = ? ERESTARTSYS (To be restarted if SA_RESTART is set) <5.577417>
>
> [pid 22046] 02:53:03.352001 futex(0x7f54707a40a0, FUTEX_WAIT_PRIVATE, 0, NULL <unfinished ...>
>
> [pid 22045] 02:53:03.352016 epoll_wait(5,  <unfinished ...>
>
> [pid 22040] 02:53:03.352049 futex(0x7f54707a00e0, FUTEX_WAIT_PRIVATE, 0, NULL <unfinished ...>
>
> [pid 22044] 02:53:03.352142 futex(0x7f54707a10c8, FUTEX_WAIT_PRIVATE, 0, NULL <unfinished ...>
>
> [pid 22046] 02:54:33.552465 +++ killed by SIGKILL +++
>
> [pid 22045] 02:54:33.552485 +++ killed by SIGKILL +++
>
> [pid 22044] 02:54:33.552494 +++ killed by SIGKILL +++
>
> 02:54:33.559654 +++ killed by SIGKILL +++
>
> root at evo-ptx-h-re1:~#    
>
>  
>
>  
>
>  
>
> systemd service files:
>
>  
>
> root at evo-ptx-h-re1:~# cat   /lib/systemd/system/dhclient.service
>
> [Unit]
>
> Description=Dynamic Host Configuration Protocol (DHCP)
>
> RequiresOverridable=network at vmb.service
>
> Before=ypbind.service
>
> After=syslog.target network.target network at vmb.service
>
>  
>
> [Service]
>
> Type=forking
>
> PIDFile=/var/run/dhclient.pid
>
> EnvironmentFile=-/etc/default/dhcp-client
>
> ExecStart=/sbin/dhclient -cf /etc/dhcp/dhclient.conf -q -lf /var/lib/dhcp/dhclient.leases $INTERFACES
>
> #ExecStart=/usr/bin/strace -ttT -s 100 -ff /sbin/dhclient -cf /etc/dhcp/dhclient.conf -q -lf /var/lib/dhcp/dhclient.leases $INTERFACES
>
> Restart=on-failure
>
> RestartSec=1
>
>  
>
> [Install]
>
> WantedBy=multi-user.target network-online.target
>
>  
>
>  
>
>  
>
>  
>
>  
>
>  
>
>  
>
> root at evo-ptx-h-re1:~# cat   /lib/systemd/system/dhcpd.service
>
> [Unit]
>
> Description=DHCPv4 Server Daemon
>
> Documentation=man:dhcpd(8) man:dhcpd.conf(5)
>
> After=network.target
>
> After=time-sync.target
>
> Wants=network at vib.service
>
> After=network at vib.service
>
>  
>
> [Service]
>
> PIDFile=/var/run/dhcpd.pid
>
> EnvironmentFile=/etc/default/dhcp-server
>
> EnvironmentFile=-/etc/sysconfig/dhcp-server
>
> ExecStartPre=/bin/touch /var/lib/dhcp/dhcpd.leases
>
> ExecStart=/usr/sbin/dhcpd -f -cf /etc/dhcp/dhcpd.conf -pf /var/run/dhcpd.pid $DHCPDARGS -q $INTERFACES
>
>  
>
> [Install]
>
> WantedBy=multi-user.target
>
> root at evo-ptx-h-re1:~#
>
>  
>
>  
>
>  
>
> _______________________________________________
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> dhcp-users at lists.isc.org
> https://lists.isc.org/mailman/listinfo/dhcp-users

-- 
PAVEL ZHUKOV
SOFTWARE ENGINEER, RHCE, RHCVA
Red Hat 
pzhukov at redhat.com    IM: IRC: landgraf