postgres.git / summary / log / commit / refs

commit    7b955c2279f4b485f328a95bf60a3cdf048b6e2d
Author:   David Rowley <drowley@postgresql.org>
Date:     Thu Oct 30 01:51:08 2025 +0000
First released in: 13.23, 14.20, 15.15, 16.11, 17.7, 18.1

    Fix bogus use of "long" in AllocSetCheck()
    
    Because long is 32-bit on 64-bit Windows, it isn't a good datatype to
    store the difference between 2 pointers.  The under-sized type could
    overflow and lead to scary warnings in MEMORY_CONTEXT_CHECKING builds,
    such as:
    
    WARNING:  problem in alloc set ExecutorState: bad single-chunk %p in block %p
    
    However, the problem lies only in the code running the check, not from
    an actual memory accounting bug.
    
    Fix by using "Size" instead of "long".  This means using an unsigned
    type rather than the previous signed type.  If the block's freeptr was
    corrupted, we'd still catch that if the unsigned type wrapped.  Unsigned
    allows us to avoid further needless complexities around comparing signed
    and unsigned types.
    
    Author: David Rowley <dgrowleyml@gmail.com>
    Reviewed-by: Michael Paquier <michael@paquier.xyz>
    Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
    Backpatch-through: 13
    Discussion: https://postgr.es/m/CAApHDvo-RmiT4s33J=aC9C_-wPZjOXQ232V-EZFgKftSsNRi4w@mail.gmail.com


 src/backend/utils/mmgr/aset.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/backend/utils/mmgr/aset.c b/src/backend/utils/mmgr/aset.c
index 3c70a7b5f24..2f1007ad7d1 100644
--- a/src/backend/utils/mmgr/aset.c
+++ b/src/backend/utils/mmgr/aset.c
@@ -1429,9 +1429,9 @@ AllocSetCheck(MemoryContext context)
 		 prevblock = block, block = block->next)
 	{
 		char	   *bpoz = ((char *) block) + ALLOC_BLOCKHDRSZ;
-		long		blk_used = block->freeptr - bpoz;
-		long		blk_data = 0;
-		long		nchunks = 0;
+		Size		blk_used = block->freeptr - bpoz;
+		Size		blk_data = 0;
+		Size		nchunks = 0;
 
 		if (set->keeper == block)
 			total_allocated += block->endptr - ((char *) set);


[parent: d91620406ae9]