On 8/30/22 03:16, David Rowley wrote: > On Tue, 30 Aug 2022 at 12:45, David Rowley <dgrowle...@gmail.com> wrote: >> I think the existing sentinel check looks wrong: >> >> if (!sentinel_ok(chunk, slab->chunkSize)) >> >> shouldn't that be passing the pointer rather than the chunk? > > Here's v2 of the slab-fix patch. > > I've included the sentinel check fix. This passes make check-world > for me when do a 32-bit build on my x86_64 machine and adjust > pg_config.h to set MAXIMUM_ALIGNOF to 8. > > Any chance you could run make check-world on your 32-bit Raspberry PI? >
Will do, but I think the sentinel fix should be if (!sentinel_ok(chunk, Slab_CHUNKHDRSZ + slab->chunkSize)) which is what the other contexts do. However, considering check-world passed even before the sentinel_ok fix, I'm a bit skeptical about that proving anything. FWIW I added a WARNING to SlabCheck before the condition guarding the sentinel check, printing the (full) chunk size and header size, and this is what I got in test_decoding (deduplicated): armv7l (32-bit rpi4) +WARNING: chunkSize 216 fullChunkSize 232 header 16 +WARNING: chunkSize 64 fullChunkSize 80 header 16 aarch64 (64-bit rpi4) +WARNING: chunkSize 304 fullChunkSize 320 header 16 +WARNING: chunkSize 80 fullChunkSize 96 header 16 So indeed, those are *perfect* matches and thus the sentinel_ok() never executed. So no failures until now. On x86-64 I get the same thing as on aarch64. I guess that explains why it never failed. Seems like a pretty amazing coincidence ... > I'm also wondering if this should also be backpatched back to v10, > providing the build farm likes it well enough on master. I'd say the sentinel fix may need to be backpatched. regard -- Tomas Vondra EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company