Has anybody seen this problem before?

[utzoo!duke!decvax!ucbvax!greg at NPRDC]

From: greg at NPRDC
I am having a problem, the symptoms of which are as follows:  a kernel
buffer is acquired (via NODEV) and a data structure built in it.  The
structure is immediately used (within the same system call), and it is
OK.  Sometime later, an attempt to use the data structure bombs, and
a dump of the buffer shows that it apparently contains a disk record.
The buffer is still correctly assigned to NODEV; just the data has been
changed.  It acts as if the buffer was assigned (maybe to a read-ahead
block?), and then freed (and reassigned to NODEV) before the I/O had
completed.  Has anybody seen this before?  Is there a cure?
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