Is "vm_fault" a kernel bug here?

[Martin]

Here is the result of a read access on a file, which is obviously
unreadable:

acd0: FAILURE - READ BIG status=51<READY,DSC,ERROR> sensekey=MEDIUM
ERROR error=4<ABORTED>
vm_fault: pager read error, pid 606 (cp)
cp: filename: Bad address

I want to report it, because of the "vm_fault", it sounds "scary".
Is this a correct behaviour or a bug in the kernel?

(FYI: With pre-BETA kernels I got a panic at this point. I recompiled
with some debug options and I get just the message above.)

Martin