Applications looking up the own computer name are blocked for several seconds

[Clemens Eisserer]

Hi,

After a system update 2-3 weeks ago, applications like java and
firefox began to take a quite long time to start up (an extra ~10s).
However this only occurs when I am connected to a network, when my
laptop is running unconnected everything is fine (however it doesn't
matter wether I am connected at home or in the office, so the cause is
not a malfunction of my DNS server).

Today I tried to find out what is going on and it seems the
applications are stalled while looking up the hostname of my own
machine ("user-pc").
Shouldn't in this case the lookup return immediantly?
As I haven't changed my configuration at all, any idea which update
introduced this issue?

Thank you in advance, Clemens

Stacktrace of firefox starting up:

#0  0x0000003fd7aeb7fd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x0000003fd9e0ad0d in send_dg (resplen2=0x0, anssizp2=0x0,
ansp2=0x0, anscp=0x7fffeeec0970, gotsomewhere=<synthetic pointer>,
v_circuit=<synthetic pointer>, ns=0, terrno=0x7fffeeebf8f0,
anssizp=0x7fffeeebfa30, ansp=0x7fffeeebf8e8, buflen2=0, buf2=0x0,
buflen=32, buf=0x7fffeeebfa60 ";\327\001", statp=0x3fd7dbeaa0
<_res@GLIBC_2.2.5>) at res_send.c:1059
#2  __libc_res_nsend (statp=statp@entry=0x3fd7dbeaa0
<_res@GLIBC_2.2.5>, buf=buf@entry=0x7fffeeebfa60 ";\327\001",
buflen=<optimized out>, buf2=buf2@entry=0x0, buflen2=buflen2@entry=0,
ans=ans@entry=0x7fffeeec0540 "", anssiz=anssiz@entry=1024,
ansp=ansp@entry=0x7fffeeec0970, ansp2=ansp2@entry=0x0,
nansp2=nansp2@entry=0x0, resplen2=resplen2@entry=0x0) at
res_send.c:556
#3  0x0000003fd9e08c47 in __GI___libc_res_nquery
(statp=statp@entry=0x3fd7dbeaa0 <_res@GLIBC_2.2.5>,
name=name@entry=0x7fffeeec00c0 "user-pc.3.home", class=class@entry=1,
type=type@entry=1, answer=answer@entry=0x7fffeeec0540 "",
anslen=anslen@entry=1024, answerp=answerp@entry=0x7fffeeec0970,
answerp2=answerp2@entry=0x0, nanswerp2=nanswerp2@entry=0x0,
resplen2=resplen2@entry=0x0) at res_query.c:226
#4  0x0000003fd9e096ab in __libc_res_nquerydomain (resplen2=0x0,
nanswerp2=0x0, answerp2=0x0, answerp=0x7fffeeec0970, anslen=1024,
answer=0x7fffeeec0540 "", type=1, class=1, domain=<optimized out>,
name=0x7fffeeec1538 "user-pc", statp=0x3fd7dbeaa0 <_res@GLIBC_2.2.5>)
at res_query.c:582
#5  __GI___libc_res_nsearch (statp=0x3fd7dbeaa0 <_res@GLIBC_2.2.5>,
name=name@entry=0x7fffeeec1538 "user-pc", class=class@entry=1,
type=type@entry=1, answer=answer@entry=0x7fffeeec0540 "",
anslen=anslen@entry=1024, answerp=0x7fffeeec0970,
answerp2=answerp2@entry=0x0, nanswerp2=nanswerp2@entry=0x0,
resplen2=resplen2@entry=0x0) at res_query.c:416
#6  0x00007fd0409e17e4 in __GI__nss_dns_gethostbyname3_r
(name=name@entry=0x7fffeeec1538 "user-pc", af=af@entry=2,
result=result@entry=0x7fffeeec0f00, buffer=buffer@entry=0x7fffeeec0f20
"\177", buflen=buflen@entry=1024, errnop=errnop@entry=0x7fd04e259690,
h_errnop=h_errnop@entry=0x7fffeeec0ef4, ttlp=ttlp@entry=0x0,
canonp=canonp@entry=0x0) at nss_dns/dns-host.c:192
#7  0x00007fd0409e1af0 in _nss_dns_gethostbyname_r
(name=0x7fffeeec1538 "user-pc", result=0x7fffeeec0f00,
buffer=0x7fffeeec0f20 "\177", buflen=1024, errnop=0x7fd04e259690,
h_errnop=0x7fffeeec0ef4) at nss_dns/dns-host.c:273
#8  0x0000003fd7b0ebd3 in __gethostbyname_r (name=0x7fffeeec1538
"user-pc", resbuf=0x7fffeeec0f00, buffer=0x7fffeeec0f20 "\177",
buflen=1024, result=0x7fffeeec0ef8, h_errnop=0x7fffeeec0ef4) at
../nss/getXXbyYY_r.c:263
#9  0x0000003fe921b467 in PR_GetHostByName () from /lib64/libnspr4.so
#10 0x00007fd04b25f8fa in nsProfileLock::LockWithSymlink(nsIFile*,
bool) () from /usr/lib64/firefox/xulrunner/libxul.so
#11 0x00007fd04b25fe92 in nsProfileLock::Lock(nsIFile*,
nsIProfileUnlocker**) () from /usr/lib64/firefox/xulrunner/libxul.so
#12 0x00007fd04b26073b in nsToolkitProfileLock::Init(nsIFile*,
nsIFile*, nsIProfileUnlocker**) () from
/usr/lib64/firefox/xulrunner/libxul.so
#13 0x00007fd04b260784 in
nsToolkitProfileLock::Init(nsToolkitProfile*, nsIProfileUnlocker**) ()
from /usr/lib64/firefox/xulrunner/libxul.so
#14 0x00007fd04b260837 in nsToolkitProfile::Lock(nsIProfileUnlocker**,
nsIProfileLock**) () from /usr/lib64/firefox/xulrunner/libxul.so
#15 0x00007fd04b25a4ca in XREMain::XRE_mainStartup(bool*) () from
/usr/lib64/firefox/xulrunner/libxul.so
#16 0x00007fd04b25b338 in XREMain::XRE_main(int, char**, nsXREAppData
const*) () from /usr/lib64/firefox/xulrunner/libxul.so
#17 0x00007fd04b25b5d3 in XRE_main () from
/usr/lib64/firefox/xulrunner/libxul.so
#18 0x0000000000403d2f in do_main(int, char**, nsIFile*) ()
#19 0x00000000004034fc in main ()

[Edik Landaveri]

Clemens,

Have you find out this on a particular network? I.e. a business, job, etc. Some companies are mostly windows shops that run extra software like AV detector, compliance rules that add overhead while you open up a browser or turn it on. Safe Connect is an example of this. Have you try this on your own home network and find any difference?

[Sam Varshavchik]

Clemens Eisserer writes:
> Hi,
>
> After a system update 2-3 weeks ago, applications like java and
> firefox began to take a quite long time to start up (an extra ~10s).
> However this only occurs when I am connected to a network, when my
> laptop is running unconnected everything is fine (however it doesn't
> matter wether I am connected at home or in the office, so the cause is
> not a malfunction of my DNS server).
>
> Today I tried to find out what is going on and it seems the
> applications are stalled while looking up the hostname of my own
> machine ("user-pc").
> Shouldn't in this case the lookup return immediantly?

Actually, according to your stacktrace below, the DNS lookup is for "user-pc. 
3.home".

What happens when you execute

dig user-pc.3.home a

[Clemens Eisserer]

Hi Sam,
> Actually, according to your stacktrace below, the DNS lookup is for
> "user-pc.3.home".
>
> What happens when you execute

I get the usual lag (~5s) and after this the following output:

[ce@user-pc ~]$ dig user-pc.3.home a
; <<>> DiG 9.9.3-rl.13207.22-P2-RedHat-9.9.3-5.P2.fc19 <<>> user-pc.3.home a
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 15712
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;user-pc.3.home.            IN    A

;; AUTHORITY SECTION:
.            3600    IN    SOA    a.root-servers.net.
nstld.verisign-grs.com. 2013112301 1800 900 604800 86400

;; Query time: 4301 msec
;; SERVER: 192.168.1.1#53(192.168.1.1)
;; WHEN: Sat Nov 23 14:53:06 EST 2013
;; MSG SIZE  rcvd: 107

Regards, Clemens