BUG #17355: Server crashes on ExecReScanForeignScan in postgres_fdw when accessing foreign partition

The following bug has been logged on the website:

Bug reference:      17355
Logged by:          Alexander Lakhin
Email address:      exclusion@gmail.com
PostgreSQL version: 14.1
Operating system:   Ubuntu 20.04
Description:

When running the following script (with 20 concurrent insert/update/delete
queries):
cat << 'EOF' | psql postgres
CREATE EXTENSION postgres_fdw;

CREATE SERVER testserver1 FOREIGN DATA WRAPPER postgres_fdw;
DO $d$
    BEGIN
        EXECUTE $$CREATE SERVER loopback FOREIGN DATA WRAPPER postgres_fdw
            OPTIONS (dbname '$$||current_database()||$$',
                     port '$$||current_setting('port')||$$'
            )$$;
    END;
$d$;

CREATE USER MAPPING FOR CURRENT_USER SERVER loopback;
CREATE TABLE async_pt (a int, b int) PARTITION BY RANGE (a);
CREATE TABLE base_tbl2 (a int, b int);
CREATE FOREIGN TABLE async_p2 PARTITION OF async_pt FOR VALUES FROM (2000)
TO (3000)
  SERVER loopback OPTIONS (table_name 'base_tbl2');
CREATE TABLE async_p3 PARTITION OF async_pt FOR VALUES FROM (3000) TO
(4000);
EOF

for i in `seq 20`; do
cat << 'EOF' | psql postgres >psql-$i.log &
INSERT INTO async_pt SELECT i FROM generate_series(3000, 3100) i;
DELETE FROM async_pt;
UPDATE async_pt SET a = a;
EOF
done
wait

I get crashes with the following stacktrace:
Core was generated by `postgres: law postgres [local] DELETE
                        '.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00007f0f438e6c42 in postgresReScanForeignScan (node=0x5580b57f23b8) at
postgres_fdw.c:1651
1651            if (!fsstate->cursor_exists)
(gdb) bt
#0  0x00007f0f438e6c42 in postgresReScanForeignScan (node=0x5580b57f23b8) at
postgres_fdw.c:1651
#1  0x00005580b4987bf9 in ExecReScanForeignScan (node=0x5580b57f23b8) at
nodeForeignscan.c:326
#2  0x00005580b4942c0a in ExecReScan (node=0x5580b57f23b8) at
execAmi.c:235
#3  0x00005580b49815bb in ExecProcNode (node=0x5580b57f23b8) at
../../../src/include/executor/executor.h:255
#4  0x00005580b4981e3b in ExecAppend (pstate=0x5580b57f1f48) at
nodeAppend.c:360
#5  0x00005580b4967c88 in ExecProcNodeFirst (node=0x5580b57f1f48) at
execProcnode.c:463
#6  0x00005580b495b774 in ExecProcNode (node=0x5580b57f1f48) at
../../../src/include/executor/executor.h:257
#7  0x00005580b4960373 in EvalPlanQualNext (epqstate=0x5580b57cf360) at
execMain.c:2612
#8  0x00005580b495fc99 in EvalPlanQual (epqstate=0x5580b57cf360,
relation=0x7f0f37b3d598, rti=3, 
    inputslot=0x5580b57d0540) at execMain.c:2383
#9  0x00005580b49a70ed in ExecDelete (mtstate=0x5580b57cf278,
resultRelInfo=0x5580b57cf5c8, tupleid=0x7ffdf2fa6002, 
    oldtuple=0x0, planSlot=0x5580b57dc9a8, epqstate=0x5580b57cf360,
estate=0x5580b57ceff0, processReturning=true, 
    canSetTag=true, changingPart=false, tupleDeleted=0x0, epqreturnslot=0x0)
at nodeModifyTable.c:1243
#10 0x00005580b49a95b3 in ExecModifyTable (pstate=0x5580b57cf278) at
nodeModifyTable.c:2599
#11 0x00005580b4967c88 in ExecProcNodeFirst (node=0x5580b57cf278) at
execProcnode.c:463
#12 0x00005580b495b774 in ExecProcNode (node=0x5580b57cf278) at
../../../src/include/executor/executor.h:257
#13 0x00005580b495e392 in ExecutePlan (estate=0x5580b57ceff0,
planstate=0x5580b57cf278, use_parallel_mode=false, 
    operation=CMD_DELETE, sendTuples=false, numberTuples=0,
direction=ForwardScanDirection, dest=0x5580b57dad98, 
    execute_once=true) at execMain.c:1551
#14 0x00005580b495beab in standard_ExecutorRun (queryDesc=0x5580b5711f80,
direction=ForwardScanDirection, count=0, 
    execute_once=true) at execMain.c:361
#15 0x00005580b495bc96 in ExecutorRun (queryDesc=0x5580b5711f80,
direction=ForwardScanDirection, count=0, 
    execute_once=true) at execMain.c:305
#16 0x00005580b4bd7cf8 in ProcessQuery (plan=0x5580b57d9ac0,
sourceText=0x5580b56e9440 "DELETE FROM async_pt;", 
    params=0x0, queryEnv=0x0, dest=0x5580b57dad98, qc=0x7ffdf2fa64b0) at
pquery.c:160
#17 0x00005580b4bd98b7 in PortalRunMulti (portal=0x5580b574d090,
isTopLevel=true, setHoldSnapshot=false, 
    dest=0x5580b57dad98, altdest=0x5580b57dad98, qc=0x7ffdf2fa64b0) at
pquery.c:1274
#18 0x00005580b4bd8d9d in PortalRun (portal=0x5580b574d090,
count=9223372036854775807, isTopLevel=true, run_once=true, 
    dest=0x5580b57dad98, altdest=0x5580b57dad98, qc=0x7ffdf2fa64b0) at
pquery.c:788
#19 0x00005580b4bd1bd9 in exec_simple_query (query_string=0x5580b56e9440
"DELETE FROM async_pt;") at postgres.c:1214
#20 0x00005580b4bd6ac8 in PostgresMain (argc=1, argv=0x7ffdf2fa66d0,
dbname=0x5580b5714f78 "postgres", 
    username=0x5580b5714f58 "law") at postgres.c:4486
#21 0x00005580b4afb357 in BackendRun (port=0x5580b570dab0) at
postmaster.c:4530
#22 0x00005580b4afabb2 in BackendStartup (port=0x5580b570dab0) at
postmaster.c:4252
#23 0x00005580b4af69a7 in ServerLoop () at postmaster.c:1745
#24 0x00005580b4af6104 in PostmasterMain (argc=3, argv=0x5580b56e34b0) at
postmaster.c:1417
#25 0x00005580b49e566a in main (argc=3, argv=0x5580b56e34b0) at main.c:209

postmaster.log contains:
2022-01-06 10:46:20.145 MSK [403022] ERROR:  cannot re-evaluate a Foreign
Update or Delete during EvalPlanQual
2022-01-06 10:46:20.145 MSK [403022] STATEMENT:  UPDATE async_pt SET a =
a;
2022-01-06 10:46:20.320 MSK [403059] LOG:  unexpected EOF on client
connection with an open transaction
2022-01-06 10:46:20.320 MSK [402977] LOG:  server process (PID 403043) was
terminated by signal 11: Segmentation fault
2022-01-06 10:46:20.320 MSK [402977] DETAIL:  Failed process was running:
DELETE FROM async_pt;