From mboxrd@z Thu Jan  1 00:00:00 1970
Content-Type: text/plain; charset=us-ascii
Mime-Version: 1.0 (Apple Message framework v1278)
From: Kenji Arisawa <arisawa@ar.aichi-u.ac.jp>
In-Reply-To: <ba9d398c37fc96db023fd66fe34dacf4@rei2.9hal>
Date: Sat, 25 Aug 2012 09:10:26 +0900
Content-Transfer-Encoding: quoted-printable
Message-Id: <784EF005-8F40-41C0-8C43-3504CBE399C3@ar.aichi-u.ac.jp>
References: <ba9d398c37fc96db023fd66fe34dacf4@rei2.9hal>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: Re: [9fans] dns
Topicbox-Message-UUID: af6016cc-ead7-11e9-9d60-3106f5b1d025

Hello cinap,

I got a one. I hope this a helpful.


ar% cat broken/1345779846.41356
name=3Ddns
/proc/41356/text:386 plan 9 executable
/sys/lib/acid/port
/sys/lib/acid/386
acid: abort()+0x0 /sys/src/libc/9sys/abort.c:6
ppanic(p=3D0x3975c,fmt=3D0x394ec)+0x146 /sys/src/libc/port/malloc.c:166
	pv=3D0x3e820
	msg=3D0x3f804
	v=3D0xdfffc800
	n=3D0x2c
D2B(p=3D0x3975c,v=3D0x497f8)+0x5a /sys/src/libc/port/pool.c:968
	a=3D0x497f0
poolfreel(v=3D0x497f8,p=3D0x3975c)+0x20 /sys/src/libc/port/pool.c:1192
	ab=3D0x3e820
poolfree(p=3D0x3975c,v=3D0x497f8)+0x41 /sys/src/libc/port/pool.c:1327
free(v=3D0x49800)+0x23 /sys/src/libc/port/malloc.c:250
mydnsquery(qp=3D0x88cf0,udppkt=3D0xc76f0,len=3D0x2a,medium=3D0x1)+0x185 =
/sys/src/cmd/ndb/dnresolve.c:1032
	rv=3D0xc
	domain=3D0x49800
	net=3D0x74656e2f
	conndir=3D0x74656e2f
	nci=3D0x52b59
	belen=3D0x6e2f000f
=
xmitquery(qp=3D0x88cf0,depth=3D0x1,medium=3D0x1,inns=3D0x1,obuf=3D0xc76f0,=
len=3D0x2a)+0x227 /sys/src/cmd/ndb/dnresolve.c:1114
	p=3D0xc7950
	j=3D0x1
	n=3D0x0
	buf=3D0x1b59c4c3
=
tcpquery(qp=3D0x88cf0,waitms=3D0x63f,obuf=3D0xc76f0,ibuf=3D0xa7530,depth=3D=
0x1,inns=3D0x1,len=3D0x2a,req=3D0x1d85,mp=3D0xdfffc9b4)+0xea =
/sys/src/cmd/ndb/dnresolve.c:1353
	rv=3D0x0
	endms=3D0x56ba1ef1
=
queryns(qp=3D0x88cf0,obuf=3D0xc76f0,depth=3D0x1,inns=3D0x1,waitms=3D0x63f,=
ibuf=3D0xa7530)+0x4d3 /sys/src/cmd/ndb/dnresolve.c:1428
	req=3D0xa9961d85
	len=3D0x2a
	dest=3D0xc7950
	p=3D0xc7c30
	ndest=3D0x1
	endms=3D0x56ba1dcc
	replywaits=3D0x0
	buf=3D0x9dfa996
	m=3D0x1d85
	srcip=3D0xdfffca18
	rv=3D0x9dfa996
udpquery(mntpt=3D0x3f0e0,qp=3D0x88cf0,patient=3D0x0,depth=3D0x1,inns=3D0x1=
)+0x1b7 /sys/src/cmd/ndb/dnresolve.c:1578
	ibuf=3D0xa7530
	obuf=3D0xc76f0
	fd=3D0xb
	msg=3D0x6faa
	pcntprob=3D0x3c
	reqtm=3D0x1f40
	wait=3D0x63f
	rv=3D0x87710
netquery(depth=3D0x1,qp=3D0x88cf0)+0x2b5 =
/sys/src/cmd/ndb/dnresolve.c:1660
	rv=3D0x0
	dp=3D0x6d460
	qlp=3D0x6d4fc
	lock=3D0x1
	buf=3D0x3975c
	triedin=3D0x0
	inname=3D0x1
netqueryns(qp=3D0x88cf0,nsrp=3D0x876b0,depth=3D0x1)+0x1e =
/sys/src/cmd/ndb/dnresolve.c:338
	rv=3D0x88ce8
=
issuequery(class=3D0x1,qp=3D0x88cf0,depth=3D0x0,name=3D0xdfffce13,recurse=3D=
0x0)+0x50 /sys/src/cmd/ndb/dnresolve.c:359
	nsrp=3D0x876b0
	cp=3D0x88cf0
	dbnsrp=3D0x8558
	rp=3D0x0
=
dnresolve1(name=3D0xdfffce13,type=3D0xf,class=3D0x1,req=3D0xdfffcdd8,depth=
=3D0x0,recurse=3D0x0)+0x25c /sys/src/cmd/ndb/dnresolve.c:505
	dp=3D0x6d460
	rp=3D0x0
	qp=3D0x88cf0
=
dnresolve(status=3D0xdfffcce0,depth=3D0x0,rooted=3D0x0,name=3D0xdfffce13,c=
lass=3D0x1,type=3D0xf,req=3D0xdfffcdd8,cn=3D0x0,recurse=3D0x0)+0xa8 =
/sys/src/cmd/ndb/dnresolve.c:198
	procname=3D0x9cb50
	rp=3D0x0
	drp=3D0x71a98
	nrp=3D0x9cb40
	nname=3D0x48
	dp=3D0xdfffcca8
	loops=3D0x9cb90
=
lookupqueryold(p=3D0xdfffce13,mf=3D0xbac50,req=3D0xdfffcdd8,rooted=3D0x0,j=
ob=3D0xba810,errbuf=3D0xdfffcd0c,wantsav=3D0x0)+0x70 =
/sys/src/cmd/ndb/dns.c:864
	status=3D0x0
	rp=3D0x9cb48
rwrite(job=3D0xba810,mf=3D0xbac50,req=3D0xdfffcdd8)+0x2be =
/sys/src/cmd/ndb/dns.c:838
	err=3D0x0
	cnt=3D0x1b
	send=3D0x0
	errbuf=3D0x0
	atype=3D0xdfffce2c
io()+0x39e /sys/src/cmd/ndb/dns.c:532
	req=3D0x1
	mdata=3D0x32
	n=3D0x32
	job=3D0xba810
	mf=3D0xbac50
main(argv=3D0xdfffefb0,argc=3D0x0)+0x32c /sys/src/cmd/ndb/dns.c:267
	ext=3D0x0
	_argc=3D0x72
	_args=3D0xdfffefc7
	servefile=3D0x642f7323
	dir=3D0x0
	kid=3D0x0
_main+0x31 /sys/src/libc/386/main9.s:16
acid:=20
echo kill > /proc/41356/ctl
ar%=20

Kenji Arisawa

On 2012/08/21, at 20:27, cinap_lenrek@gmx.de wrote:

> nothing wrong with diffing the changes and see if theres a clue, but
> to solve this one really needs to find the underlying cause no matter
> what. changes can just hide bugs or make them more or less likely to
> appear. can anyone provide at least a stacktrace or process snapshot
> of the crashed dns processes? from that you try to build a theory of
> what might be going wrong by thinking really really hard... (the
> thinking should be directly proportional to the time it takes to
> reproduce the bug) and then you work on how to prove that theory.
> just changing stuff without knowing what exactly was the problem with
> the old code is sometimes tempting, but wrong and dangerous.
>=20
> --
> cinap
>=20