BUG #18658: Assert in SerialAdd() due to race condition

The following bug has been logged on the website:

Bug reference:      18658
Logged by:          Andrew Bille
Email address:      andrewbille@gmail.com
PostgreSQL version: 17.0
Operating system:   Ubuntu 20.04
Description:

Hello!

The following script against a server (master c259b1578) compiled with
-DTEST_SUMMARIZE_SERIAL (without the define it's harder to reproduce...):

echo "CREATE TABLE t(f1 int);" | psql test

for i in seq 100; do
    echo "
    SET default_transaction_isolation to 'SERIALIZABLE';
    SELECT 'INSERT INTO t VALUES(42);' FROM generate_series(1, 100) g
    \gexec
    " | psql -q test &

    echo "
    SET default_transaction_isolation to 'SERIALIZABLE';
    SELECT 'INSERT INTO t VALUES(42);' FROM generate_series(1, 100) g
    \gexec
    " | psql -q test &

    wait

    grep 'TRAP:' server.log && break;
done

fails for me with the following stack trace:
#5  0x000055e6aaf3fef5 in ExceptionalCondition
(conditionName=conditionName@entry=0x55e6ab1232d1
"TransactionIdIsValid(tailXid)", fileName=fileName@entry=0x55e6ab1231d9
"predicate.c", lineNumber=lineNumber@entry=886) at assert.c:66
#6  0x000055e6aadcde64 in SerialAdd (xid=976743,
minConflictCommitSeqNo=18446744073709551615) at predicate.c:886
#7  0x000055e6aadd0877 in SummarizeOldestCommittedSxact () at
predicate.c:1521
#8  0x000055e6aadd094f in GetSerializableTransactionSnapshotInt
(snapshot=snapshot@entry=0x55e6ab32f3e0 <CurrentSnapshotData>,
sourcevxid=sourcevxid@entry=0x0, sourcepid=sourcepid@entry=-1) at
predicate.c:1789
#9  0x000055e6aadd2a51 in GetSerializableTransactionSnapshot
(snapshot=snapshot@entry=0x55e6ab32f3e0 <CurrentSnapshotData>) at
predicate.c:1693
#10 0x000055e6aaf868c4 in GetTransactionSnapshot () at snapmgr.c:257
#11 0x000055e6aade2d9a in exec_simple_query
(query_string=query_string@entry=0x55e6ab433fe0 "SELECT 'INSERT INTO t
VALUES(42);' FROM generate_series(1, 100) g\n        ") at postgres.c:1173
#12 0x000055e6aade516f in PostgresMain (dbname=<optimized out>,
username=<optimized out>) at postgres.c:4793
#13 0x000055e6aadde301 in BackendMain (startup_data=<optimized out>,
startup_data_len=<optimized out>) at backend_startup.c:107
#14 0x000055e6aad2cbf8 in postmaster_child_launch
(child_type=child_type@entry=B_BACKEND,
startup_data=startup_data@entry=0x7ffc1ca820e4 "",
startup_data_len=startup_data_len@entry=4,
client_sock=client_sock@entry=0x7ffc1ca82120)
    at launch_backend.c:274
#15 0x000055e6aad30e72 in BackendStartup
(client_sock=client_sock@entry=0x7ffc1ca82120) at postmaster.c:3420
#16 0x000055e6aad31092 in ServerLoop () at postmaster.c:1653
#17 0x000055e6aad324e6 in PostmasterMain (argc=argc@entry=3,
argv=argv@entry=0x55e6ab42e390) at postmaster.c:1351
#18 0x000055e6aac48bd7 in main (argc=3, argv=0x55e6ab42e390) at main.c:197

This is also reproduced on dafaa3efb
    Implement genuine serializable isolation level.
    
...

Thanks, Andrew