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colag
Tux's lil' helper
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Joined: 26 Sep 2009
Posts: 100
Location: Dhaka, Bangladesh

PostPosted: Sat Oct 15, 2016 9:50 am    Post subject: Why isn't kernel starting with init=/bin/bash? Reply with quote

It's not related to gentoo. Gentoo stage3 is not extracted in /media/sda7. /dev/sda7 is empty ext4 partition. It has only glibc,binutils,ncurses,readline,bash and kernel is in /boot/vmlinuz-4.8.0.
Code:

linux   /boot/vmlinuz-4.8.0 root=/dev/sda7 ro init=/bin/bash

Error after booting:
Code:

kernel panic - not syncing: Attempted to kill inint !
bash not painted

I've installed glibc,binutils,ncurses,readline,bash in /dev/sda7 from /dev/sda9. Debian system is in /dev/sda9
I installed glibc,binutils,ncurses,readline,bash in this way:
Code:

glibc:
cd /media/sda7/packages/glibc-2.24
./configure --prefix=/media/sda7 --enable-kernel=2.6.32
make
make install

binutils:
cd /media/sda7/packages/binutils-2.27
./configure --prefix=/media/sda7
make
make install

ncurses:
cd /media/sda7/packages/ncurses-5.9
./configure --prefix=/media/sda7 --with-shared --with-termlib
make
make install

readline:
cd /media/sda7/packages/readline-6.3
./configure --prefix=/media/sda7
make
make install

bash:
cd /media/sda7/packages/bash-4.4
./configure --prefix=/media/sda7
make
make install

Bash is there.
Code:

mount /dev/sda7 /media/sda7
cd /media/sda7/bin
ls | grep bash
bash
bashbug

cd /media/sda7/lib
ls | grep libc
libc-2.24.so
libc.a
libcidn-2.24.so
libcidn.so
libcidn.so.1
libc_nonshared.a
libcrypt-2.24.so
libcrypt.a
libcrypt.so
libcrypt.so.1
libc.so
libc.so.6

ls | grep libtinfo
libtinfo.a
libtinfo_g.a
libtinfo.so
libtinfo.so.5
libtinfo.so.5.9

ls | grep ncurses
libncurses.a
libncurses++.a
libncurses_g.a
libncurses.so
libncurses.so.5
libncurses.so.5.9

ls | grep ld
ld-2.24.so
ld-linux.so.2


grub.cfg
Code:

menuentry 'Kernel boot with bash' --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-69b65444-5f22-4b9b-9afc-3a815c0d44b8' {
    load_video
    insmod gzio
    insmod part_msdos
    insmod ext2
    set root='hd0,msdos7'
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  69b65444-5f22-4b9b-9afc-3a815c0d44b8
    else
      search --no-floppy --fs-uuid --set=root 69b65444-5f22-4b9b-9afc-3a815c0d44b8
    fi 
    echo    'Loading Linux 4.8.0 ...'
    linux   /boot/vmlinuz-4.8.0 root=/dev/sda7 ro init=/bin/bash
}


Am I missing anything to install? Is the glibc installed properly? Are all requiredl shared library loaded correctly? How can I check if glibc is ok?
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NeddySeagoon
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Joined: 05 Jul 2003
Posts: 43183
Location: 56N 3W

PostPosted: Sat Oct 15, 2016 10:15 am    Post subject: Reply with quote

colag,

Code:
$ ls /lib/ld* -l
-rwxr-xr-x 1 root root 144616 Apr  9  2016 /lib/ld-2.22.so
lrwxrwxrwx 1 root root     10 Apr  9  2016 /lib/ld-linux-x86-64.so.2 -> ld-2.22.so


Do ls /bin/bash and look at the ELF header.

Code:
Program Headers:
  Type           Offset   VirtAddr           PhysAddr           FileSiz  MemSiz   Flg Align
  PHDR           0x000040 0x0000000000400040 0x0000000000400040 0x000230 0x000230 R E 0x8
  INTERP         0x000270 0x0000000000400270 0x0000000000400270 0x00001c 0x00001c R   0x1
      [Requesting program interpreter: /lib64/ld-linux-x86-64.so.2]

On my install /lib and /lib64 are symlinked together.

Notice that when bash loads, it wants to use /lib64/ld-linux-x86-64.so.2, which is a symlink to the linker.
Is your ld-linux-x86-64.so.2 -> ld-2.22.so symlink name correct?

If not bash cannot load as it cannot be linked.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.
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colag
Tux's lil' helper
Tux's lil' helper


Joined: 26 Sep 2009
Posts: 100
Location: Dhaka, Bangladesh

PostPosted: Sat Oct 15, 2016 10:23 am    Post subject: Reply with quote

NeddySeagoon,
Code:

ls -l /media/sda7/lib/ld*
-rwxr-xr-x 1 root root 725744 Oct 15  lib/ld-2.24.so
lrwxrwxrwx 1 root root     10 Oct 15    lib/ld-linux.so.2 -> ld-2.24.so

ls /bin/bash
/bin/bash

ls /media/sda7/bin/bash
/media/sda7/bin/bash

ls /bin/bash didn't match the output of yours.
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NeddySeagoon
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Joined: 05 Jul 2003
Posts: 43183
Location: 56N 3W

PostPosted: Sat Oct 15, 2016 10:57 am    Post subject: Reply with quote

colag,

What matters is that all your pieces are self consistent.

Your
Code:
[Requesting program interpreter: /lib64/ld-linux-x86-64.so.2]
from your /bin/bash must point (via several symlinks if needed) to your /lib/ld-...
If that's incorrect, /bin/bash will load, fail to find the dynamic linker, then you get that error about bash.

You need to answer the question about your system being self consistent.

I have met this issue before. Cross compiled programs for a Raspberry Pi failed to run on the target because of exactly this issue.
Natively build programs and cross compiled programs used different names for the linker in the ELF header.
Adding a symlink so both names worked, fixed it.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.
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colag
Tux's lil' helper
Tux's lil' helper


Joined: 26 Sep 2009
Posts: 100
Location: Dhaka, Bangladesh

PostPosted: Sat Oct 15, 2016 11:38 am    Post subject: Reply with quote

NeddySeagoon,
Quote:

What matters is that all your pieces are self consistent.
You need to answer the question about your system being self consistent.

What does that mean? I think, everything in debian system is self consistent/stable.
Code:

readelf -l /media/sda7/bin/bash | grep ': /lib'
[Requesting program interpreter: /lib/ld-linux.so.2]

But this returns nothing:
Code:

readelf -l /media/sda7/bin/bash | grep ': /media/sda7/lib'

Is this ok?
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NeddySeagoon
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Joined: 05 Jul 2003
Posts: 43183
Location: 56N 3W

PostPosted: Sat Oct 15, 2016 2:52 pm    Post subject: Reply with quote

colag,

That's OK because /media/sda7/lib is the path to your chrooted /lib from outside the chroot.
When you chroot or boot the kernel in /sda7 the bash ELF header says to use the linker at /lib/ld-linux.so.2

Going back to a previous post, you said
Code:
ls -l /media/sda7/lib/ld*
-rwxr-xr-x 1 root root 725744 Oct 15  lib/ld-2.24.so
lrwxrwxrwx 1 root root     10 Oct 15    lib/ld-linux.so.2 -> ld-2.24.so


So the bash ELF header points to /lib/ld-linux.so.2, which in turn is a link to ld-2.24.so, which exits in your filesystem.
That's good. It rules out not finding the linker as a cause.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.
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szatox
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Joined: 27 Aug 2013
Posts: 1746

PostPosted: Sun Oct 16, 2016 7:49 pm    Post subject: Reply with quote

Hint:
create link named "sh" pointing to /bin/busybox
and set init to that link.

Once you boot into the minimal shell, try calling /bin/bash. And check the error it throws. File not found by any chance?
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