when pgbackrest execute backup, press Ctrl+C, many cause core-dump

[Wim1234]

Please provide the following information when submitting an issue (feature requests or general comments can skip this):

1. pgBackRest version: 2.27

2. PostgreSQL version: 12.0

3. Operating system/version - if you have more than one server (for example, a database server, a repository host server, one or more standbys), please specify each: CentOS7.6

4. Did you install pgBackRest from source or from a package? Yes

5. Please attach the following as applicable:

   • pgbackrest.conf file(s)
   • postgresql.conf settings applicable to pgBackRest (archive_command, archive_mode, listen_addresses, max_wal_senders, wal_level, port)
   • errors in the postgresql log file before or during the time you experienced the issue
   • log file in /var/log/pgbackrest for the commands run (e.g. /var/log/pgbackrest/mystanza_backup.log)

6. Describe the issue:

   1. build pgbackrest from 2.27 source code
   2. two node, pg 12.0, one primary + one standby
   3. config the pgbackrest.conf
   4. after stanza-create, backup work normally
   5. but, when backup doing , press Ctrl+C, many cause core-dump,
   6. does not occur everytime, but about 20% possible
   7. add some log statement in the pgbackrest source-code,build and test again

   8. when core-dump, the log show: protocolClientFreeResource 0x11111111 protocolClientFreeResource 0x22222222 protocolClientFreeResource 0x33333333 memContextFree RETHROW callback:0xabababab argu: 0x33333333 dbFreeResouce DB: 0x8888888 ProtocolClient: 0x111111111

      Because protocolClient 0x111111 ALREADY released, dbFreeResouce will core-dump because access INVALID memory

   how to avoid this? why ?

[dwsteele]

It looks like the frees are running in the wrong order here. We'll have a look at it.