IndexBuild Function call fcinfo cannot access memory

Dear hackers,

Currently, I am developing a backend index access method for my research
project.

I built corresponding routines such as MyIndexbuild, MyIndexInsert, and so
on and put them in "src/backend/access/hippo" (hippo is my index's name). I
also added new entries in corresponding catalog files:

src/include/catalog/pg_am.h
src/include/catalog/pg_amop.h
src/include/catalog/pg_amproc.h
src/include/catalog/pg_opclass.h
src/include/catalog/pg_opfamily.h
src/include/catalog/pg_proc.h

Now I can successfully build/query/update my new index by executing PG
source code regression test (make check). Everything looks fine.

However, these methods don't work in the normal PG server. It gave me
"segmentation fault"

I entered this SQL command in psql:
create index hippo_idx on hippo_tbl using hippo(id2);

Then got:
Segmentation fault (core dumped)

Here is my backtrace. It looks like I cannot access fcinfo. Can you help me
about this? Or just some hints? I have been struggling with this problem
for weeks.

Thank you all in advance!

----------------------------------------
#0 0x00000000004673d2 in hippobuild (
fcinfo=<error reading variable: Cannot access memory at address
0x7fff3092c188>) at hippo.c:154
#1 0x0000000000956e64 in OidFunctionCall3Coll (functionId=5005,
collation=0,
arg1=140162511383536, arg2=140162511390256, arg3=19885792) at
fmgr.c:1649
#2 0x0000000000555809 in index_build (heapRelation=0x7f7a20b3abf0,
indexRelation=0x7f7a20b3c630, indexInfo=0x12f6ee0, isprimary=0 '\000',
isreindex=0 '\000') at index.c:2025
#3 0x0000000000554551 in index_create (heapRelation=0x7f7a20b3abf0,
indexRelationName=0x12f9378 "hippo_idx", indexRelationId=20668,
relFileNode=0, indexInfo=0x12f6ee0, indexColNames=0x12f7370,
accessMethodObjectId=5000, tableSpaceId=0, collationObjectId=0x12f7990,
classObjectId=0x12f79b0, coloptions=0x12f79d0, reloptions=19895952,
isprimary=0 '\000', isconstraint=0 '\000', deferrable=0 '\000',
initdeferred=0 '\000', allow_system_table_mods=0 '\000',
skip_build=0 '\000', concurrent=0 '\000', is_internal=0 '\000',
if_not_exists=0 '\000') at index.c:1100
#4 0x000000000062727b in DefineIndex (relationId=12476, stmt=0x12f6ff8,
indexRelationId=0, is_alter_table=0 '\000', check_rights=1 '\001',
skip_build=0 '\000', quiet=0 '\000') at indexcmds.c:606
#5 0x00000000008077a6 in ProcessUtilitySlow (parsetree=0x127c740,
queryString=0x127ba48 "create index hippo_idx on hippo_tbl using
hippo(id2) with (density=20);\n", context=PROCESS_UTILITY_TOPLEVEL,
params=0x0,
dest=0xe19a40 <debugtupDR>, completionTag=0x7fff7819aae0 "")
at utility.c:1260
#6 0x0000000000806c30 in standard_ProcessUtility (parsetree=0x127c740,
queryString=0x127ba48 "create index hippo_idx on hippo_tbl using
hippo(id2) with (density=20);\n", context=PROCESS_UTILITY_TOPLEVEL,
params=0x0,
dest=0xe19a40 <debugtupDR>, completionTag=0x7fff7819aae0 "")
at utility.c:893
#7 0x0000000000805d81 in ProcessUtility (parsetree=0x127c740,
queryString=0x127ba48 "create index hippo_idx on hippo_tbl using
hippo(id2) with (density=20);\n", context=PROCESS_UTILITY_TOPLEVEL,
params=0x0,
dest=0xe19a40 <debugtupDR>, completionTag=0x7fff7819aae0 "")
at utility.c:335
#8 0x0000000000804dd3 in PortalRunUtility (portal=0x12f0d88,
utilityStmt=0x127c740, isTopLevel=1 '\001', dest=0xe19a40 <debugtupDR>,
completionTag=0x7fff7819aae0 "") at pquery.c:1187
#9 0x0000000000804fa1 in PortalRunMulti (portal=0x12f0d88,
isTopLevel=1 '\001', dest=0xe19a40 <debugtupDR>,
altdest=0xe19a40 <debugtupDR>, completionTag=0x7fff7819aae0 "")
at pquery.c:1318
#10 0x00000000008044e5 in PortalRun (portal=0x12f0d88,
count=9223372036854775807, isTopLevel=1 '\001',
dest=0xe19a40 <debugtupDR>, altdest=0xe19a40 <debugtupDR>,
completionTag=0x7fff7819aae0 "") at pquery.c:816
#11 0x00000000007fe2af in exec_simple_query (
query_string=0x127ba48 "create index hippo_idx on hippo_tbl using
hippo(id2) with (density=20);\n") at postgres.c:1104
#12 0x00000000008025af in PostgresMain (argc=6, argv=0x1244a40,
dbname=0x124c3a0 "postgres", username=0x124c3a0 "postgres")
at postgres.c:4025
#13 0x00000000006d3513 in main (argc=6, argv=0x1244a40) at main.c:219