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5265e91fd changed MemoryContextContains to update it so that it works correctly with the new MemoryChunk code added in c6e0fe1f2. However, 5265e91fd was done with the assumption that MemoryContextContains would only ever be given pointers to memory that had been returned by one of our MemoryContext allocators. It seems that's not true and many of our 32-bit buildfarm animals are clearly showing that. There are some code paths that call MemoryContextContains with a pointer pointing part way into an allocated chunk. The example of this found by the 32-bit buildfarm animals is the int2int4_sum() function. This function returns transdata->sum, which is not a pointer to memory that was allocated directly. This return value is then subsequently passed to MemoryContextContains which causes it to crash due to it thinking the memory directly prior to that pointer is a MemoryChunk. What's actually in that memory is the field in the struct that comes prior to the "sum" field. This problem didn't occur in 64-bit world because BIGINT is a byval type and the code which was calling MemoryContextContains with the bad pointer only does so with non-byval types. Here, instead of reverting 5265e91fd and making MemoryContextContains completely broken again, let's just make it always return false for now. Effectively prior to 5265e91fd it was doing that anyway, this at least makes that more explicit. The only repercussions of this with the current MemoryContextContains calls are that we perform a datumCopy() when we might not need to. This should make the 32-bit buildfarm animals happy again and give us more time to consider a long-term fix. Discussion: https://postgr.es/m/20220907130552.sfjri7jublfxyyi4%40jrouhaud
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/.