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Date:      Sun, 1 Feb 2004 14:29:32 -0600
From:      Dan Nelson <dnelson@allantgroup.com>
To:        Joe Schmoe <non_secure@yahoo.com>
Cc:        freebsd-hackers@freebsd.org
Subject:   Re: What kind of a crash is this ? (kernel ?  userland ?)
Message-ID:  <20040201202932.GA25030@dan.emsphone.com>
In-Reply-To: <20040201020256.17498.qmail@web21501.mail.yahoo.com>
References:  <20040201020256.17498.qmail@web21501.mail.yahoo.com>

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In the last episode (Jan 31), Joe Schmoe said:
> I have become familiar with certain FreeBSD crashes - namely, I can
> tell the difference between the kernel crashing, and the userland
> crashing.
>  
> If the machine is down, but I can still ping it, then the userland
> has crashed - the kernel is still running, which is why it responds
> to pings.

"userland" doesn't crash (except maybe if you break libc.so).  Rather,
one binary most likely is not running.  You may be able to telnet in if
ssh is not running, for example.
  
> But if it crashes and just reboots itself, then the kernel has
> crashed.  Oversimplified I know, but I am leading up to:
>  
> What kind of a crash is it if:
>  
> I can ssh to the system, it gives me the BSD copyright and the uname
> message, but never ever gives me a prompt.  What is going on in this
> scenario ?  What kind of things have you seen that cause a crash like
> this ?

Hit ^T and find out what command on the remote side is currently
running, and what it's waiting on.  Could be DNS, a remote NFS server
not responding, local disk problems, etc.

-- 
	Dan Nelson
	dnelson@allantgroup.com



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