Bug: interference between two sessions

I'm seeing what looks like an ugly bug in the February 8th snapshot,
running under NetBSD/sparc 1.3.  Here's the sequence of events (note
that it's doesn't have to be this particular table; I've reproduced
this with different ones):

* I run initdb as 'postgres', and create a user 'tih'.
* As 'tih', I then create a data base 'sr11', and connect to it with psql.
* I then create a table and an index from psql, thus:

create table food_des (
    ndb_no        char(5)        not null,
    fdgp_cd        char4        not null,
    descrip        text        not null,
    shrt_desc    varchar(60)    not null,
    ref_desc    varchar(45)    not null,
    refuse        int2,
    sciname        varchar(60),
    n_factor    float4,
    pro_factor    float4,
    fat_factor    float4,
    cho_factor    float4
);

create unique index food_des_ndb_no on food_des (ndb_no);

* Then, in the psql session, I load data from an external file, thus:

copy food_des from '/u/tih/databases/SR11/food_des.load' using delimiters '^';

* While this is running, in a separate shell I try to create the default
* data base for user 'tih' (upon this error, disk activity stops):

barsoom:tih> createdb
Connection to database 'template1' failed.
PQexec() -- There is no connection to the backend.
createdb: database creation failed on tih.
barsoom:tih>

* When this happens, the postmaster process reports the following:

ERROR:  cannot write block 6 of food_des_ndb_no [sr11] blind

* The 'postmaster' and one 'postgres' process are still active.
* Further attempts at starting psql sessions will just hang.

Any ideas?  I can reproduce this easily, so I can test any time.

-tih
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