Re: SlabCheck leaks memory into TopMemoryContext

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: Andres Freund <andres@anarazel.de>, Tomas Vondra <tv@fuzzy.cz>, pgsql-hackers@postgresql.org
Date: 2020-01-16T20:15:41Z
Lists: pgsql-hackers
Tomas Vondra <tomas.vondra@2ndquadrant.com> writes:
> I think the one possible argument against this approach might be that it
> adds a field to the struct, so if you have an extension using a Slab
> context, it'll break if you don't rebuild it. But that only matters if
> we want to backpatch it (which I think is not the plan) and with memory
> context checking enabled (which does not apply to regular packages).

Huh?  That struct is private in slab.c, no?  Any outside code relying
on its contents deserves to break.

I do think we ought to back-patch this, given the horrible results
Andres showed.

			regards, tom lane



Commits

  1. Allocate freechunks bitmap as part of SlabContext