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ProcSleep() used a PGPROC* variable to point to PROC_QUEUE->links.next, because that does "the right thing" with SHMQueueInsertBefore(). While that largely works, it's certainly not correct and unnecessary - we can just use SHM_QUEUE* to point to the insertion point. Noticed when testing a 32bit of postgres with undefined behavior sanitizer. UBSan noticed that sometimes the supposed PGPROC wasn't sufficiently aligned (required since 46d6e5f5679, ensured indirectly, via ShmemAllocRaw() guaranteeing cacheline alignment). For now fix this by using a SHM_QUEUE* for the insertion point. Subsequently we should replace all the use of PROC_QUEUE and SHM_QUEUE with ilist.h, but that's a larger change that we don't want to backpatch. Backpatch to all supported versions - it's useful to be able to run postgres under UBSan. Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/20221117014230.op5kmgypdv2dtqsf@awork3.anarazel.de Backpatch: 11-
PostgreSQL Database Management System ===================================== This directory contains the source code distribution of the PostgreSQL database management system. PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download/ See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.