sysresccd crashed during fdisk [solved]

Topics about disk partitioning (fdisk, parted, gparted, partimage), Volumes Management (lvm, evms, dmraid), Storage, file systems, ...
josephg
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sysresccd crashed during fdisk [solved]

Postby josephg » 12 Jan 2016, 16:19

after i successfully gparted creating/modifying some partitions, i noticed that the partition numbers were not in order. so i used fdisk x to fix partition order, and i think the system hung during fdisk write table to disk. i waited for a while, but i didn't see any further activity. keyboard was not responsive either. so i long press power button to force power off.

now i can't boot. grub successfully loads boot menu, but i can't boot any of the grub menu items.

when i boot again from sysresccd, i see messages like:

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>> Attempting to mount device: /dev/sda1
>> Attempting to mount device: /dev/sda2
>> Attempting to mount device: /dev/sda3
..
>> Attempting to mount device: /dev/sda255

and then the boot continues again

and gets stuck at the following stage

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 * Populating /dev with existing devices through uevents ...         [ ok ]
 * Waiting for uevents to be processed ...


it seems like i have now ended up with 255 partitions on /dev/sda numbered 1..255, but i can't confirm till i end up at a console prompt.

i think all my data is still intact, and only the partition table has been corrupted.
what can i do to recover my partition table? sysresccd hangs during boot, as above.
Last edited by josephg on 12 Jan 2016, 18:14, edited 3 times in total.

gernot
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Joined: 07 Apr 2010, 16:19

Re: sysresccd crashed during fdisk

Postby gernot » 12 Jan 2016, 17:07

Use a liveCD and restore your partitiontable with testdisk.
Sysresccd could work if you boot from CD which is found before probing bad /dev/sda.

You can also try gparted live cd which contain also testdisk. There is a demonstration video on youtube.

Gernot

josephg
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Re: sysresccd crashed during fdisk

Postby josephg » 12 Jan 2016, 18:05

i used sysresccd usb-boot. could that have caused this problem? i noticed the usb lights furiously blinking when the system hung during fdisk write.

i have just downloaded gparted-live-0.24.0-2-i586.iso, and written to cd. i'm trying that now, and will report back here.. thanks again!

josephg
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Re: sysresccd crashed during fdisk

Postby josephg » 12 Jan 2016, 18:37

i'm having trouble booting gparted livecd.. it seems to get stuck somewhere.

i turned on verbose bootoption. i can see it listing sda: sda1 sda2 ... sda155 sda156. no more.

i'm listing all boot errors and last few messages where boot seems to get stuck

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Failed to find cpu0 device node

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modprobe: can't load module crc32c_intel (kernel/arch/x86/crypto/crc32c-intel.ko): No such device

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modprobe: module dm-raid45 not found in modules.dep

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overlayfs: missing 'workdir'


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mounting root fiilesystem..

i will confirm the above next time i boot

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perf interrupt took too long (5003 > 5000), lowering kernel.per_event_max_sample_rate to 25000


lots of these boot messages every few minutes.. each time with diff numbers

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Out of memory: Kill process 57 (systemd-udevd) score 220 or sacrifice child
Killed process 57 (systemd-udevd) total-vm:710380kB, anon-rss:699208kB, file-rss:4024kB


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 INFO: task systemd1 blocked for more than 120 seconds.
       Not tainted 4.2.0-1-586 #1


then loads of these

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 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
 INFO: systemd-udevd:691 blocked for more than 120 seconds.
       Not tainted 4.2.0-1-586 #1
Last edited by josephg on 12 Jan 2016, 19:56, edited 2 times in total.

josephg
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Re: sysresccd crashed during fdisk

Postby josephg » 12 Jan 2016, 18:38

i checked md5sum, sha1sum, sha256sum.. all ok!

josephg
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Re: sysresccd crashed during fdisk

Postby josephg » 12 Jan 2016, 18:45

good news i suppose.. i have reached the console prompt after a 10min long boot.. whew!
just started testdisk.. analysing now

system hung again.. so power-off and waiting for boot to finish.. which ended in kernel panic :(

i going to burn sysresccd, and try without that systemd stuff in gpartedlive

josephg
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Re: sysresccd crashed during fdisk

Postby josephg » 12 Jan 2016, 19:26

gernot wrote:Sysresccd could work if you boot from CD which is found before probing bad /dev/sda.

i burnt systemrescuecd-x86-4.7.0.iso to cd, and booted it up. no boot errors, but boot is stuck. last few boot messages are

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 * Starting udev ...                                                  [ ok ]
 * Generating a rule to create a /dev/root symlink ...                [ ok ]
 * Populating /dev with existing devices through uevents ...          [ ok ]
 * Waiting for uevents to be processed ...


keyboard works, but boot is going nowhere :(

gernot
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Joined: 07 Apr 2010, 16:19

Re: sysresccd crashed during fdisk

Postby gernot » 12 Jan 2016, 20:07

I have no idea why sysresccd freeze.

Try gparted live CD .
You can check the harddisk for hardware problems with smartctl.

Gernot

p,s. sometime booting continue after pressing [ctrl] c

josephg
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Re: sysresccd crashed during fdisk

Postby josephg » 12 Jan 2016, 21:13

i think they aren't able to handle so many disk partitions.. particularly when these partitions fail to read. yet they keep trying.. i've now tried sysresccd, gparted live, alt linux rescue, .. no go :(

ctrl+c works. as do keystrokes and i can see them on the screen. but ctrl+c doesn't seem to interrupt the boot process

i wonder if there is any rescue disk which does not insist on reading the harddisk and creating all these devices at boot. perhaps i could manually detect and create the disk devices after boot.

can sysresccd do so?

josephg
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Re: sysresccd crashed during fdisk

Postby josephg » 13 Jan 2016, 03:09

none of the rescue systems i tried could cope with all those spurious devices. i think udev couldn't deal with it, and wouldn't let go either.

i installed openbsd with testdisk on a usb stick, and booted. clean boot, flawless testdisk, and i got some partitions back. openbsd couldn't deal with the btrfs and fat32 partitions. i tried a few iterations. then went back to sysresccd bootusb, and testdisk found all the other partitions too. success!

thank you gernot for your support


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