self-deadlock at FATAL exit of boostrap process on read error

I encounter a situation that the server can't shutdown when a boostrap
process does ReadBuffer() but gets an read error. I guess the problem may be
like this - the boostrap process can't read at line:

smgrread(reln->rd_smgr, blockNum, (char *) bufBlock);

So it does a FATAL exit and shmem_exit() is called:

while (--on_shmem_exit_index >= 0)
(*on_shmem_exit_list[on_shmem_exit_index].function) (code,
on_shmem_exit_list[on_shmem_exit_index].arg);
Where
on_shmem_exit_list[0] = DummyProcKill
on_shmem_exit_list[1] = AtProcExit_Buffers

The above callback is called in a stack order, so AtProcExit_Buffers() will
call AbortBufferIO() which is blocked by itself on "io_in_progress_lock"
(which is not the case as the comment says "since LWLockReleaseAll has
already been called, we're not holding the buffer's io_in_progress_lock").

There may other similar problems for bootstrap process like this, so I am
not sure the best fix for this ...

Regards,
Qingqing