[SOLVED] forgot root passwd, kernel boot in single mode still asks for root passwd

nass · 05-07-2012, 06:36 AM

Hello everyone,
stupid me. I must have typed smth that I don't recall for a vm guest slackware I setup.
I reboot to single mode , but i still get a root and password prompt when loading finishes.
empty password is not allowed and i can't get access not even i single mode

(i really thought I should)

Quote:

(none) login: root
password:

I can also try to boot with kernel params:

Quote:

single init=/bin/bash

. this time I get a prompt but I can't remount / as rw, nor change the password (passwd complains it can't get a lock on /etc/shadow)

what am i forgeting?

AlleyTrotter · 05-07-2012, 07:57 AM

Boot the machine with a live DVD
then edit the /etc/passwd file
the first line should be
"root:x:0:0::/root:/bin/bash"
change it to
"root::0:0::/root:/bin/bash"
If my memory is good this gives root no password
so you just hit [ENTER] for the root login password

SORRY I missed that this was a VM

john

guanx · 05-07-2012, 08:03 AM

Quote:

Originally Posted by nass

...
I can also try to boot with kernel params: . this time I get a prompt but I can't remount / as rw
...

What's the error message?

hotchili · 05-07-2012, 08:10 AM

Basicly it should work what you are trying...

Try only init=/bin/bash no other parameters, and
then when you get the prompt: mount -o remount,rw /

nass · 05-07-2012, 08:53 AM

Alley Trotter, i can't mount the /dev/sda1.. its a jfs volume... I thought the huge kernel has the jfs compiled in or as module...
mount says " bad fs option, bad superblock".

so no chances i mount the drive...

also i really though I could do all this without the slack dvd...

nass · 05-07-2012, 09:06 AM

ok the error message is ugly:

1st attempt:

Quote:

bash4.1# mount -o remount,rw /
mount: / not mounted already, or bad option

2nd attempt

Quote:

bash4.1# mount -o remount,rw /
[ 52.254623] BUG: unabled to handle kernel NULL pointer dereference at 00...00040
[ 52.256358] IP: [<fffffffff81434235>] txBegin+0x7d/0x380
..
.
.
.
(more ugly dump following

3rd attempt
mount gets stuck somewhere and never returns a prompt... hmmmmm

it looks fairly 'outside' the norm. so i';ll assume something is really wrong and just dump the whole vm guest.. its a clean slack system either way

TobiSGD · 05-07-2012, 11:25 AM

Download the SystemRescueCD, it has comes with the ability to mount JFS. Then just chroot into your /-partition and launch passwd root to change the root password. No need for editing files.

michaelk · 05-07-2012, 12:16 PM

Try this:
linux single init=/bin/bash rw

Ref:
http://www.linuxquestions.org/questi...ion-cd-876500/

nass · 05-08-2012, 04:24 AM

Thank you guys for the vm is gone at this point (perhaps not though at the time of your posting - but I didn't check LQ)

TobiSGD i guess many live distros would let me do what you're saying, i still would have preferred to get the password pack with what slackware has laying around. Its good to know jfs is not supported by the huge kernel of the install dvd (should it not?)

Michaelk yes that seems reasonable but no need to try it now. it seems this is what i was looking for though

TobiSGD · 05-08-2012, 06:17 AM

Quote:

Originally Posted by nass

Its good to know jfs is not supported by the huge kernel of the install dvd (should it not?)

Actually it is. I just had a look and the Slackware install DVD has, after booting up, makefs.jfs available, so I think that JFS is supported.

nass · 05-08-2012, 06:25 AM

then why couldn't I just mount the drive ?:S

gnashley · 05-08-2012, 12:37 PM

I think jfs has to be checked with fsck before every mount.