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* "buffer overflow detected" when running SHOW POOL_STATUS
@ 2025-11-27 18:55 zam bak <[email protected]>
2025-11-30 01:27 ` Re: "buffer overflow detected" when running SHOW POOL_STATUS Tatsuo Ishii <[email protected]>
0 siblings, 1 reply; 6+ messages in thread
From: zam bak @ 2025-11-27 18:55 UTC (permalink / raw)
To: [email protected]
Hello
I am using the latest pgpool-II v4.6.4 on Rocky Linux v10.1
(installation via RPMs) with PostgreSQL 18 (one primary, one replica,
streaming replication)
When attempting to run POOL_STATUS command, either as SQL or via pcp,
I am getting "buffer overflow detected" in the log.
Here are the contents of the log from both SQL and pcp commands:
1)
sudo -u postgres pcp_pool_status -w -v -h localhost -p 9898 -U postgres
2025-11-27 13:30:19.298 [4486]: [3-1] user=[No Connection],db=[No
Connection],app=pcp_main LOG: forked new pcp worker, pid=4495
socket=7
2025-11-27 13:30:19.298 [4486]: [4-1] user=[No Connection],db=[No
Connection],app=pcp_main LOCATION: pcp_child.c:327
*** buffer overflow detected ***: terminated
2025-11-27 13:30:20.315 [4486]: [5-1] user=[No Connection],db=[No
Connection],app=pcp_main LOG: PCP process with pid: 4495 exits with
status 134 by signal 6
2025-11-27 13:30:20.315 [4486]: [6-1] user=[No Connection],db=[No
Connection],app=pcp_main LOCATION: pcp_child.c:394
2)
sudo -u postgres psql -w -h localhost -p 9999 -U postgres -c "SHOW POOL_STATUS"
2025-11-27 13:31:34.385 [4390]: [1-1]
user=postgres,db=postgres,app=psql LOG: DB node id: 0 backend pid:
10166 statement: SELECT pg_catalog.version()
2025-11-27 13:31:34.385 [4390]: [2-1]
user=postgres,db=postgres,app=psql LOCATION:
pool_proto_modules.c:3803
*** buffer overflow detected ***: terminated
And here is my pgpool.conf file (only changed lines - diff compared to
pgpool.conf.sample)
diff --unchanged-line-format= --old-line-format=
--new-line-format='%L' pgpool.conf.sample pgpool.conf
listen_addresses = '*'
unix_socket_directories = '/var/run/pgpool'
pcp_socket_dir = '/var/run/pgpool'
serialize_accept = on
backend_hostname0 = '192.168.68.104'
backend_port0 = 5432
backend_weight0 = 1
backend_data_directory0 = '/data/pgdata/18'
backend_flag0 = 'ALWAYS_PRIMARY'
backend_application_name0 = 'primary'
backend_hostname1 = '192.168.68.105'
backend_port1 = 5432
backend_weight1 = 1
backend_data_directory1 = '/data/pgdata/18'
backend_flag1 = 'DISALLOW_TO_FAILOVER'
backend_application_name1 = 'replica_1'
num_init_children = 96
max_pool = 2
child_life_time = 0
log_line_prefix = '%m [%p]: [%l-1] user=%u,db=%d,app=%a ' #
printf-style string to output at beginning of each log line.
log_connections = off
log_disconnections = off
log_per_node_statement = on
log_standby_delay = 'always'
log_error_verbosity = verbose # terse, default, or verbose messages
log_filename = 'pgpool-01-%a.log'
write_function_list =
'currval,lastval,nextval,setval,public.upgrade_.*,upgrade_.*,public.update_.*,update_.*,public.selsert_.*,selsert_.*,public.purge_.*,purge_.*,public.process_.*,process_.*,public.move_.*,move_.*,public.merge_.*,merge_.*,public.mark_.*,mark_.*,billing.can_ahs_claim_charge,billing.can_ahs_apply_.*'
statement_level_load_balance = on
sr_check_period = 5s
sr_check_user = 'pgpool_monitor'
delay_threshold_by_time = 500ms
health_check_period = 10
health_check_timeout = 30
health_check_user = 'pgpool_monitor'
health_check_max_retries = 10
failover_on_backend_error = off
check_temp_table = trace
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: "buffer overflow detected" when running SHOW POOL_STATUS
2025-11-27 18:55 "buffer overflow detected" when running SHOW POOL_STATUS zam bak <[email protected]>
@ 2025-11-30 01:27 ` Tatsuo Ishii <[email protected]>
2025-12-01 14:42 ` Re: "buffer overflow detected" when running SHOW POOL_STATUS zam bak <[email protected]>
0 siblings, 1 reply; 6+ messages in thread
From: Tatsuo Ishii @ 2025-11-30 01:27 UTC (permalink / raw)
To: [email protected]; +Cc: [email protected]
Hello,
Thank you for the report!
Unfortunately, I was not able to reproduce the issue on my Ubuntu 24
and Rocky Linux 10.1 box (pgpool is compiled from source code).
So there are some questions:
- Is the issue occurred even when you execute other pgpool command?
(for example "show pool_processes")
- I found a problem with the output of "show pool_status". The value
of "memqcache_stats_start_time" is shown with newline and an empty
item followed. I am not sure if this is related to your issue. If
possible, can you please try the attached patch?
Best regards,
--
Tatsuo Ishii
SRA OSS K.K.
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp
> Hello
>
> I am using the latest pgpool-II v4.6.4 on Rocky Linux v10.1
> (installation via RPMs) with PostgreSQL 18 (one primary, one replica,
> streaming replication)
> When attempting to run POOL_STATUS command, either as SQL or via pcp,
> I am getting "buffer overflow detected" in the log.
> Here are the contents of the log from both SQL and pcp commands:
>
> 1)
> sudo -u postgres pcp_pool_status -w -v -h localhost -p 9898 -U postgres
>
> 2025-11-27 13:30:19.298 [4486]: [3-1] user=[No Connection],db=[No
> Connection],app=pcp_main LOG: forked new pcp worker, pid=4495
> socket=7
> 2025-11-27 13:30:19.298 [4486]: [4-1] user=[No Connection],db=[No
> Connection],app=pcp_main LOCATION: pcp_child.c:327
> *** buffer overflow detected ***: terminated
> 2025-11-27 13:30:20.315 [4486]: [5-1] user=[No Connection],db=[No
> Connection],app=pcp_main LOG: PCP process with pid: 4495 exits with
> status 134 by signal 6
> 2025-11-27 13:30:20.315 [4486]: [6-1] user=[No Connection],db=[No
> Connection],app=pcp_main LOCATION: pcp_child.c:394
>
> 2)
> sudo -u postgres psql -w -h localhost -p 9999 -U postgres -c "SHOW POOL_STATUS"
>
> 2025-11-27 13:31:34.385 [4390]: [1-1]
> user=postgres,db=postgres,app=psql LOG: DB node id: 0 backend pid:
> 10166 statement: SELECT pg_catalog.version()
> 2025-11-27 13:31:34.385 [4390]: [2-1]
> user=postgres,db=postgres,app=psql LOCATION:
> pool_proto_modules.c:3803
> *** buffer overflow detected ***: terminated
>
>
>
> And here is my pgpool.conf file (only changed lines - diff compared to
> pgpool.conf.sample)
> diff --unchanged-line-format= --old-line-format=
> --new-line-format='%L' pgpool.conf.sample pgpool.conf
>
> listen_addresses = '*'
> unix_socket_directories = '/var/run/pgpool'
> pcp_socket_dir = '/var/run/pgpool'
> serialize_accept = on
> backend_hostname0 = '192.168.68.104'
> backend_port0 = 5432
> backend_weight0 = 1
> backend_data_directory0 = '/data/pgdata/18'
> backend_flag0 = 'ALWAYS_PRIMARY'
> backend_application_name0 = 'primary'
> backend_hostname1 = '192.168.68.105'
> backend_port1 = 5432
> backend_weight1 = 1
> backend_data_directory1 = '/data/pgdata/18'
> backend_flag1 = 'DISALLOW_TO_FAILOVER'
> backend_application_name1 = 'replica_1'
> num_init_children = 96
> max_pool = 2
> child_life_time = 0
> log_line_prefix = '%m [%p]: [%l-1] user=%u,db=%d,app=%a ' #
> printf-style string to output at beginning of each log line.
> log_connections = off
> log_disconnections = off
> log_per_node_statement = on
> log_standby_delay = 'always'
> log_error_verbosity = verbose # terse, default, or verbose messages
> log_filename = 'pgpool-01-%a.log'
> write_function_list =
> 'currval,lastval,nextval,setval,public.upgrade_.*,upgrade_.*,public.update_.*,update_.*,public.selsert_.*,selsert_.*,public.purge_.*,purge_.*,public.process_.*,process_.*,public.move_.*,move_.*,public.merge_.*,merge_.*,public.mark_.*,mark_.*,billing.can_ahs_claim_charge,billing.can_ahs_apply_.*'
> statement_level_load_balance = on
> sr_check_period = 5s
> sr_check_user = 'pgpool_monitor'
> delay_threshold_by_time = 500ms
> health_check_period = 10
> health_check_timeout = 30
> health_check_user = 'pgpool_monitor'
> health_check_max_retries = 10
> failover_on_backend_error = off
> check_temp_table = trace
>
>
Attachments:
[text/x-patch] pool_status.patch (615B, 2-pool_status.patch)
download | inline diff:
diff --git a/src/utils/pool_process_reporting.c b/src/utils/pool_process_reporting.c
index e4fcf4457..9e677d95e 100644
--- a/src/utils/pool_process_reporting.c
+++ b/src/utils/pool_process_reporting.c
@@ -1117,6 +1117,8 @@ get_config(int *nrows)
StrNCpy(status[i].name, "memqcache_stats_start_time", POOLCONFIG_MAXNAMELEN);
snprintf(status[i].value, POOLCONFIG_MAXVALLEN, "%s", ctime(&pool_get_memqcache_stats()->start_time));
+ /* remove a newline added by ctime() */
+ *(strchrnul(status[i].value, '\n')) = '\0';
StrNCpy(status[i].desc, "Start time of query cache stats", POOLCONFIG_MAXDESCLEN);
i++;
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: "buffer overflow detected" when running SHOW POOL_STATUS
2025-11-27 18:55 "buffer overflow detected" when running SHOW POOL_STATUS zam bak <[email protected]>
2025-11-30 01:27 ` Re: "buffer overflow detected" when running SHOW POOL_STATUS Tatsuo Ishii <[email protected]>
@ 2025-12-01 14:42 ` zam bak <[email protected]>
2025-12-02 05:02 ` Re: "buffer overflow detected" when running SHOW POOL_STATUS Tatsuo Ishii <[email protected]>
0 siblings, 1 reply; 6+ messages in thread
From: zam bak @ 2025-12-01 14:42 UTC (permalink / raw)
To: Tatsuo Ishii <[email protected]>; +Cc: [email protected]
On Sat, Nov 29, 2025 at 8:27 PM Tatsuo Ishii <[email protected]> wrote:
>
> Hello,
>
> Thank you for the report!
>
> Unfortunately, I was not able to reproduce the issue on my Ubuntu 24
> and Rocky Linux 10.1 box (pgpool is compiled from source code).
> So there are some questions:
>
> - Is the issue occurred even when you execute other pgpool command?
> (for example "show pool_processes")
No. Only getting this issue when running SHOW POOL_STATUS
>
> - I found a problem with the output of "show pool_status". The value
> of "memqcache_stats_start_time" is shown with newline and an empty
> item followed. I am not sure if this is related to your issue. If
> possible, can you please try the attached patch?
I suspect you want me to compile it from source (after applying this patch).
I don't have the setup for this unfortunately.
As I mentioned, I did install from RPMs using Rocky Linux 10.1 (with
minimal install option)
Is there a way to provide RPM instead of the patch?
>
> Best regards,
> --
> Tatsuo Ishii
> SRA OSS K.K.
> English: http://www.sraoss.co.jp/index_en/
> Japanese:http://www.sraoss.co.jp
>
> > Hello
> >
> > I am using the latest pgpool-II v4.6.4 on Rocky Linux v10.1
> > (installation via RPMs) with PostgreSQL 18 (one primary, one replica,
> > streaming replication)
> > When attempting to run POOL_STATUS command, either as SQL or via pcp,
> > I am getting "buffer overflow detected" in the log.
> > Here are the contents of the log from both SQL and pcp commands:
> >
> > 1)
> > sudo -u postgres pcp_pool_status -w -v -h localhost -p 9898 -U postgres
> >
> > 2025-11-27 13:30:19.298 [4486]: [3-1] user=[No Connection],db=[No
> > Connection],app=pcp_main LOG: forked new pcp worker, pid=4495
> > socket=7
> > 2025-11-27 13:30:19.298 [4486]: [4-1] user=[No Connection],db=[No
> > Connection],app=pcp_main LOCATION: pcp_child.c:327
> > *** buffer overflow detected ***: terminated
> > 2025-11-27 13:30:20.315 [4486]: [5-1] user=[No Connection],db=[No
> > Connection],app=pcp_main LOG: PCP process with pid: 4495 exits with
> > status 134 by signal 6
> > 2025-11-27 13:30:20.315 [4486]: [6-1] user=[No Connection],db=[No
> > Connection],app=pcp_main LOCATION: pcp_child.c:394
> >
> > 2)
> > sudo -u postgres psql -w -h localhost -p 9999 -U postgres -c "SHOW POOL_STATUS"
> >
> > 2025-11-27 13:31:34.385 [4390]: [1-1]
> > user=postgres,db=postgres,app=psql LOG: DB node id: 0 backend pid:
> > 10166 statement: SELECT pg_catalog.version()
> > 2025-11-27 13:31:34.385 [4390]: [2-1]
> > user=postgres,db=postgres,app=psql LOCATION:
> > pool_proto_modules.c:3803
> > *** buffer overflow detected ***: terminated
> >
> >
> >
> > And here is my pgpool.conf file (only changed lines - diff compared to
> > pgpool.conf.sample)
> > diff --unchanged-line-format= --old-line-format=
> > --new-line-format='%L' pgpool.conf.sample pgpool.conf
> >
> > listen_addresses = '*'
> > unix_socket_directories = '/var/run/pgpool'
> > pcp_socket_dir = '/var/run/pgpool'
> > serialize_accept = on
> > backend_hostname0 = '192.168.68.104'
> > backend_port0 = 5432
> > backend_weight0 = 1
> > backend_data_directory0 = '/data/pgdata/18'
> > backend_flag0 = 'ALWAYS_PRIMARY'
> > backend_application_name0 = 'primary'
> > backend_hostname1 = '192.168.68.105'
> > backend_port1 = 5432
> > backend_weight1 = 1
> > backend_data_directory1 = '/data/pgdata/18'
> > backend_flag1 = 'DISALLOW_TO_FAILOVER'
> > backend_application_name1 = 'replica_1'
> > num_init_children = 96
> > max_pool = 2
> > child_life_time = 0
> > log_line_prefix = '%m [%p]: [%l-1] user=%u,db=%d,app=%a ' #
> > printf-style string to output at beginning of each log line.
> > log_connections = off
> > log_disconnections = off
> > log_per_node_statement = on
> > log_standby_delay = 'always'
> > log_error_verbosity = verbose # terse, default, or verbose messages
> > log_filename = 'pgpool-01-%a.log'
> > write_function_list =
> > 'currval,lastval,nextval,setval,public.upgrade_.*,upgrade_.*,public.update_.*,update_.*,public.selsert_.*,selsert_.*,public.purge_.*,purge_.*,public.process_.*,process_.*,public.move_.*,move_.*,public.merge_.*,merge_.*,public.mark_.*,mark_.*,billing.can_ahs_claim_charge,billing.can_ahs_apply_.*'
> > statement_level_load_balance = on
> > sr_check_period = 5s
> > sr_check_user = 'pgpool_monitor'
> > delay_threshold_by_time = 500ms
> > health_check_period = 10
> > health_check_timeout = 30
> > health_check_user = 'pgpool_monitor'
> > health_check_max_retries = 10
> > failover_on_backend_error = off
> > check_temp_table = trace
> >
> >
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: "buffer overflow detected" when running SHOW POOL_STATUS
2025-11-27 18:55 "buffer overflow detected" when running SHOW POOL_STATUS zam bak <[email protected]>
2025-11-30 01:27 ` Re: "buffer overflow detected" when running SHOW POOL_STATUS Tatsuo Ishii <[email protected]>
2025-12-01 14:42 ` Re: "buffer overflow detected" when running SHOW POOL_STATUS zam bak <[email protected]>
@ 2025-12-02 05:02 ` Tatsuo Ishii <[email protected]>
2025-12-02 17:31 ` Re: "buffer overflow detected" when running SHOW POOL_STATUS zam bak <[email protected]>
0 siblings, 1 reply; 6+ messages in thread
From: Tatsuo Ishii @ 2025-12-02 05:02 UTC (permalink / raw)
To: [email protected]; +Cc: [email protected]
>> Unfortunately, I was not able to reproduce the issue on my Ubuntu 24
>> and Rocky Linux 10.1 box (pgpool is compiled from source code).
>> So there are some questions:
>>
>> - Is the issue occurred even when you execute other pgpool command?
>> (for example "show pool_processes")
>
> No. Only getting this issue when running SHOW POOL_STATUS
I found a bug with SHOW POOL_STATUS (and pcp_pool_status). The bug
broke the data segment used for the conversion from binary form of
backend flag (in this case ALWAYS_PRIMARY. Other flag does not raise
the issue) to string representation, which caused the buffer overflow
issue.
Attached is the patch to fix the issue.
Best regards,
--
Tatsuo Ishii
SRA OSS K.K.
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp
Attachments:
[text/x-patch] fix_backend_flag.patch (816B, 2-fix_backend_flag.patch)
download | inline diff:
diff --git a/src/config/pool_config.l b/src/config/pool_config.l
index b16130293..defedffbd 100644
--- a/src/config/pool_config.l
+++ b/src/config/pool_config.l
@@ -6,7 +6,7 @@
* pgpool: a language independent connection pool server for PostgreSQL
* written by Tatsuo Ishii
*
- * Copyright (c) 2003-2024 PgPool Global Development Group
+ * Copyright (c) 2003-2025 PgPool Global Development Group
*
* Permission to use, copy, modify, and distribute this software and
* its documentation for any purpose and without fee is hereby
@@ -654,7 +654,7 @@ char *pool_flag_to_str(unsigned short flag)
if (*buf == '\0')
snprintf(buf, sizeof(buf), "ALWAYS_PRIMARY");
else
- snprintf(buf+strlen(buf), sizeof(buf), "|ALWAYS_PRIMARY");
+ strncat(buf, "|ALWAYS_PRIMARY", sizeof(buf));
}
return buf;
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: "buffer overflow detected" when running SHOW POOL_STATUS
2025-11-27 18:55 "buffer overflow detected" when running SHOW POOL_STATUS zam bak <[email protected]>
2025-11-30 01:27 ` Re: "buffer overflow detected" when running SHOW POOL_STATUS Tatsuo Ishii <[email protected]>
2025-12-01 14:42 ` Re: "buffer overflow detected" when running SHOW POOL_STATUS zam bak <[email protected]>
2025-12-02 05:02 ` Re: "buffer overflow detected" when running SHOW POOL_STATUS Tatsuo Ishii <[email protected]>
@ 2025-12-02 17:31 ` zam bak <[email protected]>
2025-12-03 06:29 ` Re: "buffer overflow detected" when running SHOW POOL_STATUS Tatsuo Ishii <[email protected]>
0 siblings, 1 reply; 6+ messages in thread
From: zam bak @ 2025-12-02 17:31 UTC (permalink / raw)
To: Tatsuo Ishii <[email protected]>; +Cc: [email protected]
On Tue, Dec 2, 2025 at 12:02 AM Tatsuo Ishii <[email protected]> wrote:
>
> >> Unfortunately, I was not able to reproduce the issue on my Ubuntu 24
> >> and Rocky Linux 10.1 box (pgpool is compiled from source code).
> >> So there are some questions:
> >>
> >> - Is the issue occurred even when you execute other pgpool command?
> >> (for example "show pool_processes")
> >
> > No. Only getting this issue when running SHOW POOL_STATUS
>
> I found a bug with SHOW POOL_STATUS (and pcp_pool_status). The bug
> broke the data segment used for the conversion from binary form of
> backend flag (in this case ALWAYS_PRIMARY. Other flag does not raise
> the issue) to string representation, which caused the buffer overflow
> issue.
>
> Attached is the patch to fix the issue.
Ishii-san
Thank you for finding the bug and fixing it...
I think this bug warrants a new patch release or a rebuild so we can
use the latest 4.6 in production...
Is it possible to release a new RPM build 4.6.4-2 or 4.6.5?
Regards
Z....
>
> Best regards,
> --
> Tatsuo Ishii
> SRA OSS K.K.
> English: http://www.sraoss.co.jp/index_en/
> Japanese:http://www.sraoss.co.jp
>
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: "buffer overflow detected" when running SHOW POOL_STATUS
2025-11-27 18:55 "buffer overflow detected" when running SHOW POOL_STATUS zam bak <[email protected]>
2025-11-30 01:27 ` Re: "buffer overflow detected" when running SHOW POOL_STATUS Tatsuo Ishii <[email protected]>
2025-12-01 14:42 ` Re: "buffer overflow detected" when running SHOW POOL_STATUS zam bak <[email protected]>
2025-12-02 05:02 ` Re: "buffer overflow detected" when running SHOW POOL_STATUS Tatsuo Ishii <[email protected]>
2025-12-02 17:31 ` Re: "buffer overflow detected" when running SHOW POOL_STATUS zam bak <[email protected]>
@ 2025-12-03 06:29 ` Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 6+ messages in thread
From: Tatsuo Ishii @ 2025-12-03 06:29 UTC (permalink / raw)
To: [email protected]; +Cc: [email protected]; [email protected]
>> I found a bug with SHOW POOL_STATUS (and pcp_pool_status). The bug
>> broke the data segment used for the conversion from binary form of
>> backend flag (in this case ALWAYS_PRIMARY. Other flag does not raise
>> the issue) to string representation, which caused the buffer overflow
>> issue.
>>
>> Attached is the patch to fix the issue.
>
> Ishii-san
>
> Thank you for finding the bug and fixing it...
>
> I think this bug warrants a new patch release or a rebuild so we can
> use the latest 4.6 in production...
> Is it possible to release a new RPM build 4.6.4-2 or 4.6.5?
According to our package manager (Peng Bo), she is planning to release
updated4.6.4 RPM for Rocky Linux 10 later this month.
Best regards,
--
Tatsuo Ishii
SRA OSS K.K.
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp
^ permalink raw reply [nested|flat] 6+ messages in thread
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2025-12-02 05:02 ` Tatsuo Ishii <[email protected]>
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