[pgpool-general: 9101] Segmentation fault

[Emond Papegaaij]

Hi,

Today one of our tests detected a segmentation fault in pgpool. At that
moment, the system runs with a single node, so no replication is involved.
During one of the actions, the database is restarted. This seems to match
exactly with the moment of the segmentation fault in pgpool. Below is the
backtrace. I've attached the pgpool logs. You can find the segmentation
fault at timestamp 2024-05-22T08:47:04.231172. In the kernel logs, the real
segmentation fault seems to occur a few seconds before that, at 08:47:01,
right at the moment when the database is stopped.

I've also attached the coredump itself. Ppgpool is version 4.5.2 and it was
compiled without debug symbols and with default compiler optimization. I'm
not that deep into C development, so I'm not sure if this makes much
difference on the reliability of the dump. I obtained the backtrace by
rebuilding pgpool with debug symbols (but keeping the same optimization
settings).

Best regards,
Emond

#0  pfree (pointer=0x7fdabff0fdb8) at ../../src/utils/mmgr/mcxt.c:956
#1  0x00005593b38c5be5 in MemoryContextDelete (context=0x7fdabff0fdb8) at
../../src/utils/mmgr/mcxt.c:229
#2  0x00005593b389af93 in pool_query_context_destroy
(query_context=0x5593b4b28d38) at context/pool_query_context.c:125
#3  0x00005593b3896218 in pool_sent_message_destroy
(message=0x5593b4b2b5e8) at context/pool_session_context.c:468
#4  0x00005593b3896013 in pool_remove_sent_message (kind=80 'P',
name=0x5593b4b60740 "") at context/pool_session_context.c:399
#5  0x00005593b389692f in pool_add_sent_message (message=0x5593b4b2b198) at
context/pool_session_context.c:643
#6  0x00005593b3881377 in Parse (frontend=0x5593b4b204f8,
backend=0x7fdabff096d8, len=4, contents=0x5593b4b35f98 "") at
protocol/pool_proto_modules.c:1588
#7  0x00005593b388523d in ProcessFrontendResponse (frontend=0x5593b4b204f8,
backend=0x7fdabff096d8) at protocol/pool_proto_modules.c:2833
#8  0x00005593b3879b99 in read_packets_and_process
(frontend=0x5593b4b204f8, backend=0x7fdabff096d8, reset_request=0,
state=0x7ffd95ab31b0, num_fields=0x7ffd95ab31b6, cont=0x7ffd95ab31ab
"\001\223U") at protocol/pool_process_query.c:5117
#9  0x00005593b386ccbf in pool_process_query (frontend=0x5593b4b204f8,
backend=0x7fdabff096d8, reset_request=0) at
protocol/pool_process_query.c:247
#10 0x00005593b3865174 in do_child (fds=0x5593b4b078e0) at
protocol/child.c:467
#11 0x00005593b382aa4c in fork_a_child (fds=0x5593b4b078e0, id=6) at
main/pgpool_main.c:863
#12 0x00005593b3829e30 in PgpoolMain (discard_status=0 '\000',
clear_memcache_oidmaps=0 '\000') at main/pgpool_main.c:561
#13 0x00005593b38279e6 in main (argc=2, argv=0x7ffd95ac0568) at
main/main.c:365
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