[pgpool-general: 8088] Re: Segfaults on PgPool-II 4.3.1

[KAWAMOTO Masaya]

Hello,

Sorry for the late reply.
We changed the way of shared memory access  where Seg fault orrured to a safer way.
https://git.postgresql.org/gitweb/?p=pgpool2.git;a=commit;h=f1710d86b61de476372a0086b977647156af415c

If possible, could you please use the corrent V4_3_STABLE code to check the seg fault no
longer occurs? 

Best regards.

On Thu, 14 Apr 2022 11:23:31 -0700
Gautam Bellary <gautam ¡÷ pulsasensors.com> wrote:

> Hi PgPool Team,
> 
> Is there any update on this?
> Please let us know if there are any more details we can provide.
> We continue to observe these segfaults regularly.
> 
> Thanks,
> Gautam
> 
> On Wed, Apr 6, 2022 at 6:53 AM Bo Peng <pengbo ¡÷ sraoss.co.jp> wrote:
> 
> > Hello,
> >
> > Thank you for reporting this issue.
> >
> > We are looking into this issue.
> > We will let you know when we can figure out how to fix it.
> >
> > Regards,
> >
> > On Tue, 5 Apr 2022 10:16:09 -0700
> > Gautam Bellary <gautam ¡÷ pulsasensors.com> wrote:
> >
> > > Hello PgPool Team,
> > >
> > > We've been experiencing regular segfaults from PgPool-II 4.3.1 that
> > appear
> > > to have started recently after we began using this version. Our logs
> > > include three different cases of segfaults, ("segfault at 14", "segfault
> > at
> > > 24" and "segfault at 0" in the logs) and we're seeing each segfault
> > several
> > > times a day on the master/leader instance in our production and test
> > > clusters. While these segfaults do not always have an immediate impact on
> > > connections between our servers and the database, we have observed an
> > > increasing number of "bad connection" issues over time, which we did not
> > > observe before upgrading to PgPool 4.3.1 and experiencing the segfaults.
> > >
> > > Details about our environment and the log lines for each segfault are
> > > included below, and we've attached the core dump backtraces from gdb for
> > > two of the three segfaults ("segfault at 14" and "segfault at 24"),
> > > including `bt` and `bt full`. We'll add details for "segfault at 0" here
> > or
> > > in a new thread when we're able to capture a coredump for it.
> > >
> > > Thanks,
> > > Gautam
> > >
> > > *Environment details (ubuntu-focal-20.04-amd64):*
> > >
> > >    - Cluster contains 3 PgPool nodes and 3 PSQL nodes, all on AWS EC2
> > >    instances, pgpool.conf attached.
> > >    - $ uname -a
> > >    Linux ip-172-30-166-230 5.4.0-1038-aws #40-Ubuntu SMP Fri Feb 5
> > 23:50:40
> > >    UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
> > >    - # SHOW POOL_VERSION;
> > >         pool_version
> > >    -----------------------
> > >     4.3.1 (tamahomeboshi)
> > >
> > > *Log lines for segfaults:*
> > > ISSUE 1 ("segfault at 14") - backtrace attached as
> > > "segfault_at_14_backtrace_20220405.txt":
> > > [350739.877169] pgpool[1157084]: segfault at 14 ip 000055b950530f25 sp
> > > 00007ffc9e560f50 error 6 in pgpool[55b950503000+d9000]
> > > [350739.877178] Code: 00 00 89 ef be 06 00 00 00 c7 44 24 50 01 00 00 00
> > e8
> > > ff 3e fd ff 85 c0 0f 88 a6 0f 00 00 89 ef e8 30 d0 03 00 48 8b 44 24 08
> > > <c7> 40 14 00 00 00 00 4c 8d a4 24 20 01 00 00 48 8d 35 65 19 23 00
> > >
> > > ISSUE 2 ("segfault at 24") - backtrace attached as
> > > "segfault_at_24_backtrace_20220405.txt":
> > > [410790.718731] pgpool[1354761]: segfault at 24 ip 000055b9505308fa sp
> > > 00007ffc9e560f50 error 6 in pgpool[55b950503000+d9000]
> > > [410790.718740] Code: 80 78 4c 01 75 0a 83 78 50 00 0f 84 cd 05 00 00 31
> > f6
> > > 48 8d 3d 0d ac 0b 00 e8 72 c8 02 00 e8 7d 42 fd ff 89 c7 e8 d6 89 fd ff
> > > <c7> 40 24 00 00 00 00 48 8b 05 38 89 1e 00 80 78 4c 01 0f 84 20 01
> > >
> > > ISSUE 3 ("segfault at 0") - backtrace unavailable at this time:
> > > [ 4932.453010] pgpool[53241]: segfault at 0 ip 000055ae84d76163 sp
> > > 00007ffd94e8c970 error 4 in pgpool[55ae84d2c000+d9000]
> > > [ 4932.453018] Code: 01 c5 41 8b 45 10 85 c0 0f 8f f1 00 00 00 89 35 d3
> > 60
> > > 1e 00 48 8d 35 d0 60 1e 00 48 8d 7e fc 89 0d c6 60 1e 00 e8 4d bd ff ff
> > > <8b> 38 4c 8d 68 18 83 ef 18 48 63 ff 48 89 3b e8 99 21 02 00 48 8b
> >
> >
> > --
> > Bo Peng <pengbo ¡÷ sraoss.co.jp>
> > SRA OSS, Inc. Japan
> > http://www.sraoss.co.jp/
> >


-- 
KAWAMOTO Masaya <kawamoto ¡÷ sraoss.co.jp>
SRA OSS, Inc. Japan