diff options
| -rw-r--r-- | src/backend/utils/mmgr/aset.c | 53 |
1 files changed, 33 insertions, 20 deletions
diff --git a/src/backend/utils/mmgr/aset.c b/src/backend/utils/mmgr/aset.c index 77872e77bcd..5beebc1c129 100644 --- a/src/backend/utils/mmgr/aset.c +++ b/src/backend/utils/mmgr/aset.c @@ -1076,22 +1076,22 @@ AllocSetRealloc(MemoryContext context, void *pointer, Size size) { AllocSet set = (AllocSet) context; AllocChunk chunk = AllocPointerGetChunk(pointer); - Size oldsize; + Size oldchksize; /* Allow access to private part of chunk header. */ VALGRIND_MAKE_MEM_DEFINED(chunk, ALLOCCHUNK_PRIVATE_LEN); - oldsize = chunk->size; + oldchksize = chunk->size; #ifdef MEMORY_CONTEXT_CHECKING /* Test for someone scribbling on unused space in chunk */ - if (chunk->requested_size < oldsize) + if (chunk->requested_size < oldchksize) if (!sentinel_ok(pointer, chunk->requested_size)) elog(WARNING, "detected write past chunk end in %s %p", set->header.name, chunk); #endif - if (oldsize > set->allocChunkLimit) + if (oldchksize > set->allocChunkLimit) { /* * The chunk must have been allocated as a single-chunk block. Use @@ -1111,7 +1111,7 @@ AllocSetRealloc(MemoryContext context, void *pointer, Size size) if (block->aset != set || block->freeptr != block->endptr || block->freeptr != ((char *) block) + - (oldsize + ALLOC_BLOCKHDRSZ + ALLOC_CHUNKHDRSZ)) + (oldchksize + ALLOC_BLOCKHDRSZ + ALLOC_CHUNKHDRSZ)) elog(ERROR, "could not find block containing chunk %p", chunk); /* @@ -1154,21 +1154,29 @@ AllocSetRealloc(MemoryContext context, void *pointer, Size size) #ifdef MEMORY_CONTEXT_CHECKING #ifdef RANDOMIZE_ALLOCATED_MEMORY - /* We can only fill the extra space if we know the prior request */ + + /* + * We can only randomize the extra space if we know the prior request. + * When using Valgrind, randomize_mem() also marks memory UNDEFINED. + */ if (size > chunk->requested_size) randomize_mem((char *) pointer + chunk->requested_size, size - chunk->requested_size); -#endif +#else /* - * realloc() (or randomize_mem()) will have left any newly-allocated - * part UNDEFINED, but we may need to adjust trailing bytes from the - * old allocation. + * If this is an increase, realloc() will have marked any + * newly-allocated part (from oldchksize to chksize) UNDEFINED, but we + * also need to adjust trailing bytes from the old allocation (from + * chunk->requested_size to oldchksize) as they are marked NOACCESS. + * Make sure not to mark too many bytes in case chunk->requested_size + * < size < oldchksize. */ #ifdef USE_VALGRIND - if (oldsize > chunk->requested_size) + if (Min(size, oldchksize) > chunk->requested_size) VALGRIND_MAKE_MEM_UNDEFINED((char *) pointer + chunk->requested_size, - oldsize - chunk->requested_size); + Min(size, oldchksize) - chunk->requested_size); +#endif #endif chunk->requested_size = size; @@ -1179,11 +1187,14 @@ AllocSetRealloc(MemoryContext context, void *pointer, Size size) #else /* !MEMORY_CONTEXT_CHECKING */ /* - * We don't know how much of the old chunk size was the actual - * allocation; it could have been as small as one byte. We have to be - * conservative and just mark the entire old portion DEFINED. + * We may need to adjust marking of bytes from the old allocation as + * some of them may be marked NOACCESS. We don't know how much of the + * old chunk size was the requested size; it could have been as small + * as one byte. We have to be conservative and just mark the entire + * old portion DEFINED. Make sure not to mark memory beyond the new + * allocation in case it's smaller than the old one. */ - VALGRIND_MAKE_MEM_DEFINED(pointer, oldsize); + VALGRIND_MAKE_MEM_DEFINED(pointer, Min(size, oldchksize)); #endif /* Ensure any padding bytes are marked NOACCESS. */ @@ -1200,7 +1211,7 @@ AllocSetRealloc(MemoryContext context, void *pointer, Size size) * allocated area already is >= the new size. (In particular, we will * fall out here if the requested size is a decrease.) */ - else if (oldsize >= size) + else if (oldchksize >= size) { #ifdef MEMORY_CONTEXT_CHECKING Size oldrequest = chunk->requested_size; @@ -1223,10 +1234,10 @@ AllocSetRealloc(MemoryContext context, void *pointer, Size size) size - oldrequest); else VALGRIND_MAKE_MEM_NOACCESS((char *) pointer + size, - oldsize - size); + oldchksize - size); /* set mark to catch clobber of "unused" space */ - if (size < oldsize) + if (size < oldchksize) set_sentinel(pointer, size); #else /* !MEMORY_CONTEXT_CHECKING */ @@ -1235,7 +1246,7 @@ AllocSetRealloc(MemoryContext context, void *pointer, Size size) * the old request or shrinking it, so we conservatively mark the * entire new allocation DEFINED. */ - VALGRIND_MAKE_MEM_NOACCESS(pointer, oldsize); + VALGRIND_MAKE_MEM_NOACCESS(pointer, oldchksize); VALGRIND_MAKE_MEM_DEFINED(pointer, size); #endif @@ -1258,6 +1269,7 @@ AllocSetRealloc(MemoryContext context, void *pointer, Size size) * memory indefinitely. See pgsql-hackers archives for 2007-08-11.) */ AllocPointer newPointer; + Size oldsize; /* allocate new chunk */ newPointer = AllocSetAlloc((MemoryContext) set, size); @@ -1282,6 +1294,7 @@ AllocSetRealloc(MemoryContext context, void *pointer, Size size) #ifdef MEMORY_CONTEXT_CHECKING oldsize = chunk->requested_size; #else + oldsize = oldchksize; VALGRIND_MAKE_MEM_DEFINED(pointer, oldsize); #endif |