Failing to show 'Password:' prompt

[Manolis Kiagias]

Nikos Vassiliadis wrote:
> Manolis Kiagias wrote:
>> This morning my server was unresponsive both from ssh and through
>> http. The only thing that is different on this system on a 1st of
>> month, is a dump job that runs through periodic (on a mostly inactive
>> system).
>>
>> Visiting the console, I discovered the system was still up and
>> displaying login prompt on all vtys, but after typing a username, the
>> password prompt would never appear. Keyboard was responsive and I
>> could even switch between keyboard layouts (English/Greek). Plugging
>> and and unplugging an external USB drive, showed the kernel messages
>> on tty0. Still, I could not get it to display a password prompt and
>> had to hard reboot it.
>>
>> I can't find anything in /var/log/messages either - it stops at 5.25
>> in the morning.  And the dump was not performed either (and there are
>> no traces about it in the log).
>>
>> What kind of crash could cause the password prompt to not display?
>> Ideas?
>
> Geia Manoli,
>
> A deadlock somewhere in the filesystem code would expose
> such behavior. Other subsystems may continue to work, but
> some operations, somehow related to that filesystem code,
> will wait - forever - for some locks to be released.
>
> I've seen such behavior in early RELENG_6 branch with regard
> to UFS snapshots.
>
> Nikos
>
>
Thanks Niko,

This is quite possible actually as I was using dump -L and the USB
backup disk was still mounted when I looked at the console messages.
I'll check the PR database for dump-related problems.