Date: Thu, 21 Nov 2019 18:01:52 +0100
From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: =?utf-8?Q?Ond=C5=99ej?= Jirman <ienieghapheoghaiwida@xff.cz>
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #16129: Segfault in tts_virtual_materialize in logical
 replication worker
Message-ID: <20191121170152.6vi2dly5ade6eyga@development>
References: <20191121115326.arierrbeok6we5sv@core.my.home>
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 <20191121133237.vgxoilemblaqmstu@development>
 <20191121135523.aybyo7o6yzxxungd@core.my.home>
 <20191121143503.nkdwgjwb7xjopeuq@development>
 <20191121150716.szxqukxrtpjpckm3@core.my.home>
 <20191121152732.hu6y4wzw7nkxpsvk@development>
 <20191121155707.pqkgjphh65o5fapz@core.my.home>
 <20191121160906.wpq5u6yh6pxv6hyo@development>
 <20191121163506.pfe4u3jinrjdodtx@core.my.home>
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On Thu, Nov 21, 2019 at 05:35:06PM +0100, Ondřej Jirman wrote:
>On Thu, Nov 21, 2019 at 05:09:06PM +0100, Tomas Vondra wrote:
>
>> On Thu, Nov 21, 2019 at 04:57:07PM +0100, Ondřej Jirman wrote:
>> > On Thu, Nov 21, 2019 at 04:27:32PM +0100, Tomas Vondra wrote:
>> > > On Thu, Nov 21, 2019 at 04:07:16PM +0100, Ondřej Jirman wrote:
>> > > > I've also managed to get valgrind output on the segfaulting process:
>> > > >
>> > > > https://megous.com/dl/tmp/valgrind-105524-109020.log
>> > > >
>> > > > Though it probably doesn't show much new.
>> > > >
>> > >
>> > > Is postgres actually compiled with valgrind support? What does pg_config
>> > > say?
>> >
>> > I don't see any valgrind related options in configure --help, I repackaged it
>> > just with CFLAGS set to -ggdb -Og.
>> >
>>
>> You need to use -DUSE_VALGRIND or edit pg_config_manual.h. I usually
>> just use
>>
>>   CFLAGS="-DRANDOMIZE_ALLOCATED_MEMORY -DUSE_VALGRIND -O0 -ggdb"
>>
>> which does the trick. Without the USE_VALGRIND defined, we don't include
>> the valgrind instrumentation, so I suppose the previous results are bogus.
>
>Two new valgrind logs, now with -DUSE_VALGRIND:
>
>https://megous.com/dl/tmp/valgrind-172090.log
>https://megous.com/dl/tmp/valgrind-172143.log
>

Unfortunately, I only get HTTP 403 :-(

>A lots of uninitialized 1b accesses around VARATT_IS_EXTERNAL_EXPANDED.
>
>So slot->tts_values[natt] is probably uninitialized.
>
>Which is why the backtrace had a weird value there, I guess.
>

Possibly. Something is clearly wrong.


regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services