Hi,

i accidentally tried to mount the extended partition /dev/sda4
from this disk:



Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x07ec16a2

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 104447 51200 83 Linux
/dev/sda2 104448 12687359 6291456 82 Linux swap / Solaris
/dev/sda3 12687360 222402559 104857600 83 Linux
/dev/sda4 222402560 1953525167 865561304 5 Extended
/dev/sda5 222404608 232890367 5242880 83 Linux
/dev/sda6 232892416 442607615 104857600 83 Linux
/dev/sda7 442609664 652324863 104857600 83 Linux
/dev/sda8 652326912 862042111 104857600 83 Linux
/dev/sda9 862044160 1071759359 104857600 83 Linux
/dev/sda10 1071761408 1281476607 104857600 83 Linux
/dev/sda11 1281478656 1491193855 104857600 83 Linux
/dev/sda12 1491195904 1953525167 231164632 83 Linux


which results in a hanging mount process, which cannot be killed.

I was urged to use the sysreq-key to reboot and get rid of that
process.

This happens with kernel 3.2.21 and 3.4.4.

Is this the expected bahviour?

Best regards,
mcc

On 06/27/2012 04:44:34 AM, meino.cramer@gmx.de wrote:

Hi,

i accidentally tried to mount the extended partition /dev/sda4
from this disk:



Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168
sectors

Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x07ec16a2

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 104447 51200 83 Linux
/dev/sda2 104448 12687359 6291456 82 Linux swap /
Solaris

/dev/sda3 12687360 222402559 104857600 83 Linux
/dev/sda4 222402560 1953525167 865561304 5 Extended
/dev/sda5 222404608 232890367 5242880 83 Linux
/dev/sda6 232892416 442607615 104857600 83 Linux
/dev/sda7 442609664 652324863 104857600 83 Linux
/dev/sda8 652326912 862042111 104857600 83 Linux
/dev/sda9 862044160 1071759359 104857600 83 Linux
/dev/sda10 1071761408 1281476607 104857600 83 Linux
/dev/sda11 1281478656 1491193855 104857600 83 Linux
/dev/sda12 1491195904 1953525167 231164632 83 Linux


which results in a hanging mount process, which cannot be killed.

I was urged to use the sysreq-key to reboot and get rid of that
process.

This happens with kernel 3.2.21 and 3.4.4.

Is this the expected bahviour?



I cannot tell you if kernel hanging in this case is normal.

But, if there is any problem during mount, the kernel seems to hang.
As far as I remember, it only has a very long time out, but it will
'kill' that mount request some time.

Helmut.

Helmut Jarausch writes:

> On 06/27/2012 04:44:34 AM, meino.cramer@gmx.de wrote:
> > Hi,
> >
> > i accidentally tried to mount the extended partition /dev/sda4
> > from this disk:
[...]
> > which results in a hanging mount process, which cannot be killed.
> >
> > I was urged to use the sysreq-key to reboot and get rid of that
> > process.
> >
> > This happens with kernel 3.2.21 and 3.4.4.
> >
> > Is this the expected bahviour?

At least it happens here, too. And the mount process uses 100% of one of
my cores, this was not expected.

> I cannot tell you if kernel hanging in this case is normal.
>
> But, if there is any problem during mount, the kernel seems to hang.
> As far as I remember, it only has a very long time out, but it will
> 'kill' that mount request some time.

Let's see how long 'very long' is, it's hanging for over one hour now. I
will wait some more hours, but that would be one really long timeout.

Wonko

Alex Schuster writes:

> Helmut Jarausch writes:
>
> > On 06/27/2012 04:44:34 AM, meino.cramer@gmx.de wrote:

> > > i accidentally tried to mount the extended partition /dev/sda4
> > > from this disk:
> [...]
> > > which results in a hanging mount process, which cannot be killed.

> > I cannot tell you if kernel hanging in this case is normal.
> >
> > But, if there is any problem during mount, the kernel seems to hang.
> > As far as I remember, it only has a very long time out, but it will
> > 'kill' that mount request some time.
>
> Let's see how long 'very long' is, it's hanging for over one hour now. I
> will wait some more hours, but that would be one really long timeout.

All I can say now is that the timeout, if there is one, must be larger
than 24 hours.

Isn't this weird?

Wonko

On Thu, Jun 28, 2012 at 8:45 AM, Alex Schuster <wonko@wonkology.org> wrote:
> Alex Schuster writes:
>
>> Helmut Jarausch writes:
>>
>> > On 06/27/2012 04:44:34 AM, meino.cramer@gmx.de wrote:
>
>> > > i accidentally tried to mount the extended partition /dev/sda4
>> > > from this disk:
>> [...]
>> > > which results in a hanging mount process, which cannot be killed.
>
>> > I cannot tell you if kernel hanging in this case is normal.
>> >
>> > But, if there is any problem during mount, the kernel seems to hang.
>> > As far as I remember, it only has a very long time out, but it will
>> > 'kill' that mount request some time.
>>
>> Let's see how long 'very long' is, it's hanging for over one hour now. I
>> will wait some more hours, but that would be one really long timeout.
>
> All I can say now is that the timeout, if there is one, must be larger
> than 24 hours.
>
> Isn't this weird?

Almost all cases of linux hangs I've ever experienced have been from either:

1) mount/unmount
2) insmod/rmmod

and they usually last forever. Sometimes prevent proper shutdown,
requiring SysRq magic or usually hard power-off...