klibc - Nov 2003 - problems when exec()ing /sbin/init from an initramfs

This is an early userspace type question.  I have an initramfs that does
some root device setup, then tries to mount the real root partition and
exec /sbin/init to start the real userland.  It seems to do what I want,
except that bootlogd hangs while mount /proc.  I can't seem to figure
out why.

I'm booting with init=/bin/bash.  bash is dynamically linked, and the
appropriate libs are in /lib on the initramfs.  This may be a stupid
idea, but it's only for initial testing.  

Kernel 2.6.0-test10 on ia64.

Distro is debian unstable.

I edited the /etc/init.d/bootlogd script so it would execute as "/bin/sh
-x", and I straced the daemon when it started.

Here is a transcript.  Any ideas?  I just can't fathom why proc would
hang during the mount call.

bash-2.05b# mount -t proc none /proc
bash-2.05b# mkdir /sys  
bash-2.05b# mount -t sysfs none /sys
bash-2.05b# /sbin/insmod mptbase.ko 
[random messages...]
bash-2.05b# /sbin/insmod mptscsih.ko 
bash-2.05b# /sbin/insmod sd_mod.ko  
[boatloads of messages from /sbin/hotplug & udev]
bash-2.05b# mount /udev/xscsi/pci20.01.1-1/target2/lun0/part2 /newroot/
bash-2.05b# umount /sys 
bash-2.05b# umount /proc
bash-2.05b# rm -rf /newroot/udev/*
bash-2.05b# cp -a /udev/* /newroot/udev/
bash-2.05b# cd newroot/
bash-2.05b# pivot_root . oldroot
bash-2.05b# exec /usr/sbin/chroot . /sbin/init <dev/console >dev/console
2>&1
INIT: version 2.85 booting
+ PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
+ DAEMON=/sbin/bootlogd
+ NAME=bootlogd
+ DESC=Bootlog daemon
+ PIDFILE=/var/run/bootlogd.pid
+ test -f /sbin/bootlogd
+ . /etc/default/rcS
++ TMPTIME=0
++ SULOGIN=no
++ DELAYLOGIN=yes
++ UTC=no
++ VERBOSE=yes
++ EDITMOTD=yes
++ FSCKFIX=no
+ '[' '' ']'
+ '[' start = stop ']'
+ echo -n 'Starting Bootlog daemon: '
Starting Bootlog daemon: + '[' -d /proc/1/. ']'
+ /usr/bin/strace /sbin/bootlogd -r
execve("/sbin/bootlogd", ["/sbin/bootlogd", "-r"],
[/* 13 vars */]) = 0
uname({sys="Linux", node="(none)", ...}) = 0
brk(0)                                  = 0x6000000000010000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
mmap(NULL, 16384, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0x200000000002c000
open("/etc/ld.so.preload", O_RDONLY)    = -1 ENOENT (No such file or
directory)
open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=14019, ...}) = 0
mmap(NULL, 14019, PROT_READ, MAP_PRIVATE, 3, 0) = 0x2000000000030000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
open("/lib/tls/libutil.so.1", O_RDONLY) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0002\0\1\0\0\0\240\32"...,
640) = 640
fstat(3, {st_mode=S_IFREG|0644, st_size=15704, ...}) = 0
mmap(NULL, 78984, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0x2000000000040000
mprotect(0x2000000000044000, 62600, PROT_NONE) = 0
mmap(0x2000000000050000, 16384, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 3,
0) = 0x2000000000050000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
open("/lib/tls/libc.so.6.1", O_RDONLY)  = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0002\0\1\0\0\0\0\311"...,
640) = 640
fstat(3, {st_mode=S_IFREG|0644, st_size=2304280, ...}) = 0
mmap(NULL, 2378936, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0x2000000000054000
mmap(0x2000000000284000, 81920, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 3,
0x220000) = 0x2000000000284000
mmap(0x2000000000298000, 3256, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x200000000020close(3)            
= 0
mmap(NULL, 32768, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0x200000000029c000
mmap(NULL, 16384, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0x20000000002a4000
munmap(0x2000000000030000, 14019)       = 0
rt_sigaction(SIGTERM, {0x4000000000003ef0, [], SA_RESTART}, {SIG_DFL}, 8) = 0
rt_sigaction(SIGQUIT, {0x4000000000003ef0, [], SA_RESTART}, {SIG_DFL}, 8) = 0
rt_sigaction(SIGINT, {0x4000000000003ef0, [], SA_RESTART}, {SIG_DFL}, 8) = 0
rt_sigaction(SIGTTIN, {SIG_IGN}, {SIG_DFL}, 8) = 0
rt_sigaction(SIGTTOU, {SIG_IGN}, {SIG_DFL}, 8) = 0
rt_sigaction(SIGTSTP, {SIG_IGN}, {SIG_DFL}, 8) = 0
fstat(0, {st_mode=S_IFCHR|0600, st_rdev=makedev(5, 1), ...}) = 0
stat("/", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
stat("/proc", {st_mode=S_IFDIR|0555, st_size=4096, ...}) = 0
mount("proc", "/proc", "proc", , 0

TIA,
mh

-- 
Martin Hicks                Wild Open Source Inc.
mort@wildopensource.com     613-266-2296

On Fri, 2003-11-28 at 16:01, Martin Hicks wrote:
> This is an early userspace type question.  I have an initramfs that does
> some root device setup, then tries to mount the real root partition and
> exec /sbin/init to start the real userland.  It seems to do what I want,
> except that bootlogd hangs while mount /proc.  I can't seem to figure
> out why.
Seems to be a kernel problem.  It works fine if I use an old-style
initrd.  There must be some problem with switching from ramfs / to a
real / then trying to mount /proc again.

Investigating will continue...
mh

-- 
Martin Hicks || mort@bork.org || PGP/GnuPG: 0x4C7F2BEE
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