mount of ext2fs volume stuck in "D+" state (disk uninterruptible wait)

[Kris Kennaway]

Joe Peterson wrote:
> Kris Kennaway wrote:
>> Joe Peterson wrote:
>>> I just tried (under FreeBSD 7.0-RC1) to mount an ext2fs volume - I've
>>> mounted it before with no trouble on this same FreeBSD version.  This
>>> time, mount appeared to hang.  I noticed that I can see the contents of
>>> the volume under the mount point, so the mount seemed to "work", but the
>>> process is stuff.  "ps" shows:
>>>
>>> root   1307  0.0  0.0  3156   792  p6  D+    5:21PM   0:00.00 mount
>>> /mnt/linux-home
>>>
>>> The "ps" man page says that "D" means: "Marks a process in disk (or
>>> other short term, uninterruptible) wait."
>>>
>>> Is there any way I can investigate what is going on?  I cannot umount
>>> (device busy) or break out of the mount command...
>> http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/kerneldebug.html
> 
> But unfortunately I do not have KDB and DDB compiled into the kernel.
> And, obviously, if I reboot, I will lose this opportunity.  I suspect
> this to be an intermittent thing.  Is there anything I can extract while
> the system is running that would be useful?
> 
> 	Thanks, Joe
> 
> 

You can run kgdb on /dev/mem to obtain the backtrace.

Kris