Re: introduce dynamic shared memory registry

Nathan Bossart <nathandbossart@gmail.com> writes:
> Committed.  Thanks everyone for reviewing!

Coverity complained about this:

*** CID 1586660:  Null pointer dereferences  (NULL_RETURNS)
/srv/coverity/git/pgsql-git/postgresql/src/backend/storage/ipc/dsm_registry.c: 185 in GetNamedDSMSegment()
179         }
180         else if (!dsm_find_mapping(entry->handle))
181         {
182             /* Attach to existing segment. */
183             dsm_segment *seg = dsm_attach(entry->handle);
184
>>>     CID 1586660:  Null pointer dereferences  (NULL_RETURNS)
>>>     Dereferencing a pointer that might be "NULL" "seg" when calling "dsm_pin_mapping".
185             dsm_pin_mapping(seg);
186             ret = dsm_segment_address(seg);
187         }
188         else
189         {
190             /* Return address of an already-attached segment. */

I think it's right --- the comments for dsm_attach explicitly
point out that a NULL return is possible.  You need to handle
that scenario in some way other than SIGSEGV.

            regards, tom lane