Date: Tue, 27 Sep 2022 15:07:12 -0500
From: Justin Pryzby <pryzby@telsasoft.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: pgsql-hackers@postgresql.org, Dilip Kumar <dilipbalaut@gmail.com>
Subject: Re: longfin and tamandua aren't too happy but I'm not sure why
Message-ID: <20220927200712.GH6256@telsasoft.com>
References: 
 <CA+TgmoYO5ee6EWhbxz+TE9hcSDONCJvczPNv--33Uk8Xd9tMHQ@mail.gmail.com>
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On Tue, Sep 27, 2022 at 02:55:18PM -0400, Robert Haas wrote:
> Both animals are running with -fsanitize=alignment and it's not
> difficult to believe that the commit mentioned above could have
> introduced an alignment problem where we didn't have one before, but
> without a stack backtrace I don't know how to track it down. I tried
> running those tests locally with -fsanitize=alignment and they passed.

There's one here:
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=kestrel&dt=2022-09-27%2018%3A43%3A06

/mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/access/rmgrdesc/xactdesc.c:102:30: runtime error: member access within misaligned address 0x000004125074 for type 'xl_xact_invals' (aka 'struct xl_xact_invals'), which requires 8 byte alignment

    #0 0x5b6702 in ParseCommitRecord /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/access/rmgrdesc/xactdesc.c:102:30
    #1 0xb5264d in xact_decode /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/replication/logical/decode.c:201:5
    #2 0xb521ac in LogicalDecodingProcessRecord /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/replication/logical/decode.c:119:3
    #3 0xb5e868 in pg_logical_slot_get_changes_guts /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/replication/logical/logicalfuncs.c:271:5
    #4 0xb5e25f in pg_logical_slot_get_changes /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/replication/logical/logicalfuncs.c:338:9
    #5 0x896bba in ExecMakeTableFunctionResult /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/executor/execSRF.c:234:13
    #6 0x8c7660 in FunctionNext /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/executor/nodeFunctionscan.c:95:5
    #7 0x899048 in ExecScanFetch /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/executor/execScan.c:133:9
    #8 0x89896b in ExecScan /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/executor/execScan.c:199:10
    #9 0x8c6892 in ExecFunctionScan /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/executor/nodeFunctionscan.c:270:9
    #10 0x892f42 in ExecProcNodeFirst /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/executor/execProcnode.c:464:9
    #11 0x8802dd in ExecProcNode /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/include/executor/executor.h:259:9
    #12 0x8802dd in ExecutePlan /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/executor/execMain.c:1636:10
    #13 0x8802dd in standard_ExecutorRun /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/executor/execMain.c:363:3
    #14 0x87ffbb in ExecutorRun /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/executor/execMain.c:307:3
    #15 0xc36c07 in PortalRunSelect /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/tcop/pquery.c:924:4
    #16 0xc364ca in PortalRun /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/tcop/pquery.c:768:18
    #17 0xc34138 in exec_simple_query /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/tcop/postgres.c:1238:10
    #18 0xc30953 in PostgresMain /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/tcop/postgres.c
    #19 0xb27e3f in BackendRun /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/postmaster/postmaster.c:4482:2
    #20 0xb2738d in BackendStartup /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/postmaster/postmaster.c:4210:3
    #21 0xb2738d in ServerLoop /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/postmaster/postmaster.c:1804:7
    #22 0xb24312 in PostmasterMain /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/postmaster/postmaster.c:1476:11
    #23 0x953694 in main /mnt/resource/bf/build/kestrel/HEAD/pgsql.build/../pgsql/src/backend/main/main.c:197:3
    #24 0x7f834e39a209 in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
    #25 0x7f834e39a2bb in __libc_start_main csu/../csu/libc-start.c:389:3
    #26 0x4a40a0 in _start (/mnt/resource/bf/build/kestrel/HEAD/pgsql.build/tmp_install/mnt/resource/bf/build/kestrel/HEAD/inst/bin/postgres+0x4a40a0)

Note that cfbot is warning for a different reason now:
https://cirrus-ci.com/task/5794615155490816