From: Noah Misch <noah@leadboat.com>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Avoid "you don't own a lock of type ExclusiveLock" in GRANT TABL
Date: Mon, 25 Nov 2024 22:43:34 +0000
Message-ID: <E1tFhnq-003Wc6-R0@gemulon.postgresql.org> (raw)
Avoid "you don't own a lock of type ExclusiveLock" in GRANT TABLESPACE.
This WARNING appeared because SearchSysCacheLocked1() read
cc_relisshared before catcache initialization, when the field is false
unconditionally. On the basis of reading false there, it constructed a
locktag as though pg_tablespace weren't relisshared. Only shared
catalogs could be affected, and only GRANT TABLESPACE was affected in
practice. SearchSysCacheLocked1() callers use one other shared-relation
syscache, DATABASEOID. DATABASEOID is initialized by the end of
CheckMyDatabase(), making the problem unreachable for pg_database.
Back-patch to v13 (all supported versions). This has no known impact
before v16, where ExecGrant_common() first appeared. Earlier branches
avoid trouble by having a separate ExecGrant_Tablespace() that doesn't
use LOCKTAG_TUPLE. However, leaving this unfixed in v15 could ensnare a
future back-patch of a SearchSysCacheLocked1() call.
Reported by Aya Iwata.
Discussion: https://postgr.es/m/OS7PR01MB11964507B5548245A7EE54E70EA212@OS7PR01MB11964.jpnprd01.prod.outlook.com
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/4ba84de459532a7a79616e756f8bfd45ba4b8048
Modified Files
--------------
src/backend/utils/cache/syscache.c | 15 ++++++++++-----
src/test/regress/expected/tablespace.out | 5 +++++
src/test/regress/sql/tablespace.sql | 6 ++++++
3 files changed, 21 insertions(+), 5 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: noah@leadboat.com, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Avoid "you don't own a lock of type ExclusiveLock" in GRANT TABL
In-Reply-To: <E1tFhnq-003Wc6-R0@gemulon.postgresql.org>
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