pg.ddx.io pgsql-committers@postgresql.org mailing list archivehelp / color / mirror / Atom feed
pgsql: Avoid possibly-theoretical OOM crash hazard in hash_create(). 3+ messages / 1 participants [nested] [flat]
* pgsql: Avoid possibly-theoretical OOM crash hazard in hash_create(). @ 2025-04-23 20:05 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 3+ messages in thread From: Tom Lane @ 2025-04-23 20:05 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Avoid possibly-theoretical OOM crash hazard in hash_create(). One place in hash_create() used DynaHashAlloc() as a convenient shorthand for MemoryContextAlloc(). That was fine when it was written, but it stopped being fine when 9c911ec06 changed DynaHashAlloc() to use MCXT_ALLOC_NO_OOM (mea culpa). Change the code to call plain MemoryContextAlloc() as intended. I think that this bug may be unreachable in practice, since we now always create AllocSets with some space already allocated, so that an OOM failure here for a non-shared hash table should be impossible (with a hash table name of reasonable length anyway). And there aren't enough shared hash tables to make a crash for one of those probable. Nonetheless it's clearly not operating as designed, so back-patch to v16 where 9c911ec06 came in. Reported-by: Maksim Korotkov <m.korotkov@postgrespro.ru> Author: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/219bdccd460510efaccf90b57e5e5ef2@postgrespro.ru Backpatch-through: 16 Branch ------ REL_16_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/f45bdb13397fc142bc95513783dca3e0106e57af Modified Files -------------- src/backend/utils/hash/dynahash.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) ^ permalink raw reply [nested|flat] 3+ messages in thread
* pgsql: Avoid possibly-theoretical OOM crash hazard in hash_create(). @ 2025-04-23 20:05 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 3+ messages in thread From: Tom Lane @ 2025-04-23 20:05 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Avoid possibly-theoretical OOM crash hazard in hash_create(). One place in hash_create() used DynaHashAlloc() as a convenient shorthand for MemoryContextAlloc(). That was fine when it was written, but it stopped being fine when 9c911ec06 changed DynaHashAlloc() to use MCXT_ALLOC_NO_OOM (mea culpa). Change the code to call plain MemoryContextAlloc() as intended. I think that this bug may be unreachable in practice, since we now always create AllocSets with some space already allocated, so that an OOM failure here for a non-shared hash table should be impossible (with a hash table name of reasonable length anyway). And there aren't enough shared hash tables to make a crash for one of those probable. Nonetheless it's clearly not operating as designed, so back-patch to v16 where 9c911ec06 came in. Reported-by: Maksim Korotkov <m.korotkov@postgrespro.ru> Author: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/219bdccd460510efaccf90b57e5e5ef2@postgrespro.ru Backpatch-through: 16 Branch ------ REL_17_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/e384118559ef693eaa47ba265627e2e6d8bca843 Modified Files -------------- src/backend/utils/hash/dynahash.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) ^ permalink raw reply [nested|flat] 3+ messages in thread
* pgsql: Avoid possibly-theoretical OOM crash hazard in hash_create(). @ 2025-04-23 20:05 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 3+ messages in thread From: Tom Lane @ 2025-04-23 20:05 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Avoid possibly-theoretical OOM crash hazard in hash_create(). One place in hash_create() used DynaHashAlloc() as a convenient shorthand for MemoryContextAlloc(). That was fine when it was written, but it stopped being fine when 9c911ec06 changed DynaHashAlloc() to use MCXT_ALLOC_NO_OOM (mea culpa). Change the code to call plain MemoryContextAlloc() as intended. I think that this bug may be unreachable in practice, since we now always create AllocSets with some space already allocated, so that an OOM failure here for a non-shared hash table should be impossible (with a hash table name of reasonable length anyway). And there aren't enough shared hash tables to make a crash for one of those probable. Nonetheless it's clearly not operating as designed, so back-patch to v16 where 9c911ec06 came in. Reported-by: Maksim Korotkov <m.korotkov@postgrespro.ru> Author: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/219bdccd460510efaccf90b57e5e5ef2@postgrespro.ru Backpatch-through: 16 Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/bc19f63f80109737e2610c81f65d33fc93246b2e Modified Files -------------- src/backend/utils/hash/dynahash.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) ^ permalink raw reply [nested|flat] 3+ messages in thread
end of thread, other threads:[~2025-04-23 20:05 UTC | newest] Thread overview: 3+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2025-04-23 20:05 pgsql: Avoid possibly-theoretical OOM crash hazard in hash_create(). Tom Lane <tgl@sss.pgh.pa.us> 2025-04-23 20:05 pgsql: Avoid possibly-theoretical OOM crash hazard in hash_create(). Tom Lane <tgl@sss.pgh.pa.us> 2025-04-23 20:05 pgsql: Avoid possibly-theoretical OOM crash hazard in hash_create(). Tom Lane <tgl@sss.pgh.pa.us>
This inbox is served by DDX for PostgreSQL; see mirroring instructions for how to clone and mirror all data and code used for this inbox