BUG #5628: 9.0beta4 failed automatic crash recovery

The following bug has been logged online:

Bug reference:      5628
Logged by:          Itagaki Takahiro
Email address:      itagaki.takahiro@gmail.com
PostgreSQL version: 9.0b4 (32bit)
Operating system:   Windows 7 (64bit)
Description:        9.0beta4 failed automatic crash recovery
Details:

9.0beta4 seems to fail automatic crash recovery after
some of backend processes crashed, though 8.2 succeeded
to recover. This is a rare error case, but some logic
for shared memory might be broken between versions.

I crashed a backend as a test manually with "pg_ctl kill":
  pg_ctl kill QUIT <backend-pid>

9.0 server has gone with the following logs:
----
WARNING:  terminating connection because of crash of another server process
...
LOG:  all server processes terminated; reinitializing
FATAL:  pre-existing shared memory block is still in use
HINT:  Check if there are any old server processes still running, and
terminate them.
----

But 8.2 can recover as expected:
----
WARNING:  terminating connection because of crash of another server process
...
LOG:  all server processes terminated; reinitializing
LOG:  database system was interrupted at <timestamp>
----