Re: BUG #17126: Server crashes on dropping user while enumerating owned objects that are droppped concurrently

On 2021-Jul-28, PG Bug reporting form wrote:

> Dropping a user that owns a number of procedures, while some of them are
> being dropped, can cause the server crash:
> 
> Core was generated by `postgres: law regression [local] DROP ROLE           
>                         '.
> Program terminated with signal SIGABRT, Aborted.
> #0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
> 50      ../sysdeps/unix/sysv/linux/raise.c: No such file or directory.
> (gdb) bt
> #0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
> #1  0x00007f268882b859 in __GI_abort () at abort.c:79
> #2  0x000055a23a628276 in ExceptionalCondition (conditionName=conditionName@entry=0x55a23a77fd4d "pointer != NULL", 
>     errorType=errorType@entry=0x55a23a68700b "FailedAssertion", fileName=0x7ffdf4459470 "W\202b:\242U", 
>     fileName@entry=0x55a23a7886b0 "../../../../src/include/utils/memutils.h", lineNumber=lineNumber@entry=123)
>     at assert.c:69
> #3  0x000055a23a65b46e in GetMemoryChunkContext (pointer=0x0) at ../../../../src/include/utils/memutils.h:123
> #4  pfree (pointer=pointer@entry=0x0) at mcxt.c:1171
> #5  0x000055a23a23254f in storeObjectDescription (descs=descs@entry=0x7ffdf44598b0, type=LOCAL_OBJECT, 
>     object=object@entry=0x55a23b5efe10, deptype=SHARED_DEPENDENCY_OWNER, count=count@entry=0) at pg_shdepend.c:1267

There's many places that deal correctly with the possibility that
getObjectDescription() would return NULL, but I found two places that
don't.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/