Date: Mon, 11 Mar 2002 15:24:36 -0800 From: Luigi Rizzo <rizzo@icir.org> To: hackers@freebsd.org Subject: kernel/library wierdness Message-ID: <20020311152436.A47452@iguana.icir.org>
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While observing a tcpdump output of a diskless client booting over
a slow network, I noticed a few weird access patterns to the root
filesystem -- see the tcpdump below (sorry for the long lines):
+ /sbin/init, right before running /bin/sh, reads /etc/login.conf
and then attempts 4 times to access login.conf.db.
This really looks bogus, I would expect first one attempt to
read the "db" copy, followed by access to the plaintext one.
Here not only the order seems wrong, also the number of retries
is strange.
23:38:45.270788 c.282475278 > s.2049: 112 lookup fh 965,348397/1661 "login.conf" (DF)
23:38:45.364103 s.2049 > c.282475278: reply ok 240 lookup fh 965,348397/1797 (DF)
23:38:46.905227 c.282475283 > s.2049: 116 lookup fh 965,348397/1661 "login.conf.db" (DF)
23:38:47.105798 s.2049 > c.282475283: reply ok 120 lookup ERROR: No such file or directory (DF)
23:38:47.106296 c.282475284 > s.2049: 116 lookup fh 965,348397/1661 "login.conf.db" (DF)
23:38:47.287960 s.2049 > c.282475284: reply ok 120 lookup ERROR: No such file or directory (DF)
23:38:49.290951 c.282475292 > s.2049: 116 lookup fh 965,348397/1661 "login.conf.db" (DF)
23:38:49.388328 s.2049 > c.282475292: reply ok 120 lookup ERROR: No such file or directory (DF)
23:38:49.388809 c.282475293 > s.2049: 116 lookup fh 965,348397/1661 "login.conf.db" (DF)
23:38:49.520152 s.2049 > c.282475293: reply ok 120 lookup ERROR: No such file or directory (DF)
+ ifconfig ed0, despite the fact the driver is compiled in,
still tries to lookup the module from the filesystem
(here the bug might be in sbin/ifconfig.c:ifmaybeload()
or in some of the library function that are used there):
23:39:09.451271 c.282475358 > s.2049: 108 lookup fh 965,348397/1567 "ifconfig" (DF)
23:39:09.610255 s.2049 > c.282475358: reply ok 240 lookup fh 965,348397/1590 (DF)
23:39:16.118390 c.282475378 > s.2049: 112 lookup fh 965,348397/1661 "malloc.conf" (DF)
23:39:16.269858 s.2049 > c.282475378: reply ok 120 lookup ERROR: No such file or directory (DF)
23:39:17.257558 c.282475382 > s.2049: 108 lookup fh 965,348397/2 "if_ed.ko" (DF)
23:39:17.363892 s.2049 > c.282475382: reply ok 120 lookup ERROR: No such file or directory (DF)
23:39:17.364415 c.282475383 > s.2049: 104 lookup fh 965,348397/2 "boot" (DF)
23:39:17.500753 s.2049 > c.282475383: reply ok 240 lookup fh 965,348397/1645 (DF)
23:39:17.501360 c.282475384 > s.2049: 108 lookup fh 965,348397/1645 "if_ed.ko" (DF)
23:39:17.613907 s.2049 > c.282475384: reply ok 120 lookup ERROR: No such file or directory (DF)
23:39:17.614367 c.282475385 > s.2049: 108 lookup fh 965,348397/2 "modules" (DF)
+ /etc/disktab.db is read twice in a row before accessing /etc/disktab:
23:39:26.610493 c.282475420 > s.2049: 112 lookup fh 965,348397/1661 "disktab.db" (DF)
23:39:26.708059 s.2049 > c.282475420: reply ok 120 lookup ERROR: No such file or directory (DF)
23:39:26.708550 c.282475421 > s.2049: 112 lookup fh 965,348397/1661 "disktab.db" (DF)
23:39:26.799911 s.2049 > c.282475421: reply ok 120 lookup ERROR: No such file or directory (DF)
23:39:26.800386 c.282475422 > s.2049: 108 lookup fh 965,348397/1661 "disktab" (DF)
23:39:26.893958 s.2049 > c.282475422: reply ok 240 lookup fh 965,348397/1826 (DF)
Just thought to mention them in case someone is interested in looking them up...
cheers
luigi
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