# Weird auto-remount of root fs "/" like read only

## Yczo

Hello folks. After the last upgrade i'm suffering an strange auto-remount of the root fs "/", (remounts like read only) it's temporally fixed using fsck and rebooting. But a time later of reboot, i'm working, and suddenly  the same error comes again. it's really disturbing, because force to  reboot often.

It is not a physical error. I did not have problems with badblocks. Something creates logical errors, either the auto-remount did

Surely I have something bad on the kernel, and probably i have more things there than i must.

this is my fstab:

/dev/sda6               /               ext4            noatime         0 1

/dev/sda3               /home           ext3            noatime         0 2

/dev/sda5               none            swap            sw              0 0

/dev/sr0                /media/cdrom    auto            noauto,ro,user  0 0

#/dev/fd0               /media/floppy   auto            noauto          0 0     No hay unidad de disco flsexible

proc                    /proc           proc            defaults        0 0

shm                     /dev/shm        tmpfs   nodev,nosuid,noexec     0 0

And a summary of my dmesg report

[   55.917194] EXT4-fs (sda6): re-mounted. Opts: commit=0

[10195.993335] nf_conntrack: automatic helper assignment is deprecated and it will be removed soon. Use the iptables CT target

to attach helpers instead.

[10229.239298] ata1.00: exception Emask 0x0 SAct 0xf SErr 0x0 action 0x0

[10229.239305] ata1.00: irq_stat 0x40000001

[10229.239318] ata1.00: cmd 60/80:00:a8:4d:6e/00:00:2d:00:00/40 tag 0 ncq 65536 in

[10229.239318]          res 41/40:80:1e:4e:6e/00:00:2d:00:00/00 Emask 0x409 (media error) <F>

[10229.239330] ata1.00: cmd 60/20:08:b0:98:bb/00:00:07:00:00/40 tag 1 ncq 16384 in

[10229.239330]          res 41/04:00:1e:4e:6e/00:00:2d:00:00/00 Emask 0x1 (device error)

[10229.239342] ata1.00: cmd 61/08:10:47:98:c0/00:00:37:00:00/40 tag 2 ncq 4096 out

[10229.239342]          res 41/04:00:1e:4e:6e/00:00:2d:00:00/00 Emask 0x1 (device error)

[10229.239354] ata1.00: cmd 61/28:18:17:96:21/00:00:38:00:00/40 tag 3 ncq 20480 out

[10229.239354]          res 41/04:00:1e:4e:6e/00:00:2d:00:00/00 Emask 0x1 (device error)

[10229.243923] ata1.00: configured for UDMA/133

[10229.243944] sd 0:0:0:0: [sda] Unhandled sense code

[10229.243948] sd 0:0:0:0: [sda]

[10229.243951] Result: hostbyte=0x00 driverbyte=0x08

[10229.243955] sd 0:0:0:0: [sda]

[10229.243957] Sense Key : 0x3 [current] [descriptor]

[10229.243963] Descriptor sense data with sense descriptors (in hex):

[10229.243966]         72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00

[10229.243980]         2d 6e 4e 1e

[10229.243988] sd 0:0:0:0: [sda]

[10229.243990] ASC=0x11 ASCQ=0x4

[10229.243995] sd 0:0:0:0: [sda] CDB:

[10229.243997] cdb[0]=0x28: 28 00 2d 6e 4d a8 00 00 80 00

[10229.244156] end_request: I/O error, dev sda, sector 935368775

[10229.244161] Buffer I/O error on device sda6, logical block 1336321

[10229.244164] lost page write due to I/O error on sda6

[10229.244177] sd 0:0:0:0: [sda]

[10229.244179] Result: hostbyte=0x00 driverbyte=0x08

[10229.244183] sd 0:0:0:0: [sda]

[10229.244185] Sense Key : 0xb [current] [descriptor]

[10229.244189] Descriptor sense data with sense descriptors (in hex):

[10229.244192]         72 0b 00 00 00 00 00 0c 00 0a 80 00 00 00 00 00

[10229.244206]         2d 6e 4e 1e

[10229.244213] sd 0:0:0:0: [sda]

[10229.244215] ASC=0x0 ASCQ=0x0

[10229.244219] sd 0:0:0:0: [sda] CDB:

[10229.244221] cdb[0]=0x2a: 2a 00 38 21 96 17 00 00 28 00

[10229.244233] end_request: I/O error, dev sda, sector 941725207

[10229.244251] ata1: EH complete

[10229.244268] JBD2: Detected IO errors while flushing file data on sda6-8

[10229.244281] Aborting journal on device sda6-8.

[10229.439264] EXT4-fs error (device sda6): ext4_journal_start_sb:348: Detected aborted journal

[10229.439272] EXT4-fs (sda6): Remounting filesystem read-only

[10232.111686] ata1.00: exception Emask 0x0 SAct 0x1 SErr 0x0 action 0x0

[10232.111692] ata1.00: irq_stat 0x40000008

[10232.111705] ata1.00: cmd 60/08:00:18:4e:6e/00:00:2d:00:00/40 tag 0 ncq 4096 in

[10232.111705]          res 41/40:08:1e:4e:6e/00:00:2d:00:00/00 Emask 0x409 (media error) <F>

[10232.264635] ata1.00: configured for UDMA/133

[10232.264653] sd 0:0:0:0: [sda] Unhandled sense code

[10232.264657] sd 0:0:0:0: [sda]

[10232.264660] Result: hostbyte=0x00 driverbyte=0x08

[10232.264664] sd 0:0:0:0: [sda]

[10232.264666] Sense Key : 0x3 [current] [descriptor]

[10235.143085] Descriptor sense data with sense descriptors (in hex):

[10235.143088]         72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00

[10235.143103]         2d 6e 4e 1e

[10235.143110] sd 0:0:0:0: [sda]

[10235.143113] ASC=0x11 ASCQ=0x4

[10235.143117] sd 0:0:0:0: [sda] CDB:

[10235.143119] cdb[0]=0x28: 28 00 2d 6e 4e 18 00 00 08 00

[10235.143132] end_request: I/O error, dev sda, sector 762203678

[10235.143156] ata1: EH complete

Please, anybody could help me to undesrtand and solve this problem?

Is it a driver problem?

uname -r

3.6.5-gentoo , I tried too with the stable kernel 3.5.7 with the same result

Regards.Last edited by Yczo on Fri Dec 07, 2012 11:09 am; edited 1 time in total

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## Ant P.

 *Quote:*   

> 
> 
> ```
> 
> [10229.239318] res 41/40:80:1e:4e:6e/00:00:2d:00:00/00 Emask 0x409 (media error) <F> 
> ...

 

Your hard disk has physical errors. Run a test using smartctl or gnome-disk-utility.

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## Yczo

Thank you for answer.

Ok, but when I used badblocks -nv, it did not report about problems. In the same way I could format the hdd.

I think that you're right but i'm not sure at all.

I will try with smartctl

Regards.

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## Hu

In some cases, the drive may be fine, but the cable and/or motherboard controller for the drive has failed.

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## krinn

Could happen if your bios was reset from "IDE controller running as AHCI" to "compatible mode". As it could alter lba and geometry report by the drive.

And changing disk may get some buggy bios lost and reset.

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## Yczo

Thank you all.

Ok, I will review the cable state and later i'll do a hdd reset with a middle level format

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## wcg

```

dumpe2fs -h /dev/sda6 | grep Errors

```

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