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pgsql: Prevent inconsistent use of stats entry for replication slots 3+ messages / 1 participants [nested] [flat]
* pgsql: Prevent inconsistent use of stats entry for replication slots @ 2024-06-05 23:49 Michael Paquier <michael@paquier.xyz> 0 siblings, 0 replies; 3+ messages in thread From: Michael Paquier @ 2024-06-05 23:49 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Prevent inconsistent use of stats entry for replication slots Concurrent activity around replication slot creation and drop could cause a replication slot to use a stats entry it should not have used when created, triggering an assertion failure when retrieving an inconsistent entry from the dshash table used by the stats facility. The issue is that pgstat_drop_replslot() calls pgstat_drop_entry() without checking the result. If pgstat_drop_entry() cannot free the entry related to the object dropped, pgstat_request_entry_refs_gc() should be called. AtEOXact_PgStat_DroppedStats() and surrounding routines dropping stats entries already do that. This is documented in pgstat_internal.h, but let's add a comment at the top of pgstat_drop_entry() as that can be easy to miss. Reported-by: Alexander Lakhin Author: Floris Van Nee Analyzed-by: Andres Freund Discussion: https://postgr.es/m/17947-b9554521ad963c9c@postgresql.org Backpatch-through: 15 Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/cd312adc561a0de056bbc0b0087d275bd3e9f282 Modified Files -------------- src/backend/utils/activity/pgstat_replslot.c | 5 +++-- src/backend/utils/activity/pgstat_shmem.c | 11 +++++++++++ 2 files changed, 14 insertions(+), 2 deletions(-) ^ permalink raw reply [nested|flat] 3+ messages in thread
* pgsql: Prevent inconsistent use of stats entry for replication slots @ 2024-06-05 23:49 Michael Paquier <michael@paquier.xyz> 0 siblings, 0 replies; 3+ messages in thread From: Michael Paquier @ 2024-06-05 23:49 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Prevent inconsistent use of stats entry for replication slots Concurrent activity around replication slot creation and drop could cause a replication slot to use a stats entry it should not have used when created, triggering an assertion failure when retrieving this inconsistent entry from the dshash table used by the stats facility. The issue is that pgstat_drop_replslot() calls pgstat_drop_entry() without checking the result. If pgstat_drop_entry() cannot free the entry related to the object dropped, pgstat_request_entry_refs_gc() should be called. AtEOXact_PgStat_DroppedStats() and surrounding routines dropping stats entries already do that. This is documented in pgstat_internal.h, but let's add a comment at the top of pgstat_drop_entry() as that can be easy to miss. Reported-by: Alexander Lakhin Author: Floris Van Nee Analyzed-by: Andres Freund Discussion: https://postgr.es/m/17947-b9554521ad963c9c@postgresql.org Backpatch-through: 15 Branch ------ REL_16_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/f2c922ff2fed2c17116a625ec7311e8200b1c9f2 Modified Files -------------- src/backend/utils/activity/pgstat_replslot.c | 5 +++-- src/backend/utils/activity/pgstat_shmem.c | 11 +++++++++++ 2 files changed, 14 insertions(+), 2 deletions(-) ^ permalink raw reply [nested|flat] 3+ messages in thread
* pgsql: Prevent inconsistent use of stats entry for replication slots @ 2024-06-05 23:49 Michael Paquier <michael@paquier.xyz> 0 siblings, 0 replies; 3+ messages in thread From: Michael Paquier @ 2024-06-05 23:49 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Prevent inconsistent use of stats entry for replication slots Concurrent activity around replication slot creation and drop could cause a replication slot to use a stats entry it should not have used when created, triggering an assertion failure when retrieving this inconsistent entry from the dshash table used by the stats facility. The issue is that pgstat_drop_replslot() calls pgstat_drop_entry() without checking the result. If pgstat_drop_entry() cannot free the entry related to the object dropped, pgstat_request_entry_refs_gc() should be called. AtEOXact_PgStat_DroppedStats() and surrounding routines dropping stats entries already do that. This is documented in pgstat_internal.h, but let's add a comment at the top of pgstat_drop_entry() as that can be easy to miss. Reported-by: Alexander Lakhin Author: Floris Van Nee Analyzed-by: Andres Freund Discussion: https://postgr.es/m/17947-b9554521ad963c9c@postgresql.org Backpatch-through: 15 Branch ------ REL_15_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/bfc44da2478954330233a8df8a146ee920400947 Modified Files -------------- src/backend/utils/activity/pgstat_replslot.c | 5 +++-- src/backend/utils/activity/pgstat_shmem.c | 11 +++++++++++ 2 files changed, 14 insertions(+), 2 deletions(-) ^ permalink raw reply [nested|flat] 3+ messages in thread
end of thread, other threads:[~2024-06-05 23:49 UTC | newest] Thread overview: 3+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2024-06-05 23:49 pgsql: Prevent inconsistent use of stats entry for replication slots Michael Paquier <michael@paquier.xyz> 2024-06-05 23:49 pgsql: Prevent inconsistent use of stats entry for replication slots Michael Paquier <michael@paquier.xyz> 2024-06-05 23:49 pgsql: Prevent inconsistent use of stats entry for replication slots Michael Paquier <michael@paquier.xyz>
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