diff options
Diffstat (limited to 'malloc')
| -rw-r--r-- | malloc/malloc.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/malloc/malloc.c b/malloc/malloc.c index ead9a21d81..6f77d372a8 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -1748,7 +1748,9 @@ static struct malloc_state main_arena = /* These variables are used for undumping support. Chunked are marked as using mmap, but we leave them alone if they fall into this - range. */ + range. NB: The chunk size for these chunks only includes the + initial size field (of SIZE_SZ bytes), there is no trailing size + field (unlike with regular mmapped chunks). */ static mchunkptr dumped_main_arena_start; /* Inclusive. */ static mchunkptr dumped_main_arena_end; /* Exclusive. */ @@ -3029,9 +3031,11 @@ __libc_realloc (void *oldmem, size_t bytes) if (newmem == 0) return NULL; /* Copy as many bytes as are available from the old chunk - and fit into the new size. */ - if (bytes > oldsize - 2 * SIZE_SZ) - bytes = oldsize - 2 * SIZE_SZ; + and fit into the new size. NB: The overhead for faked + mmapped chunks is only SIZE_SZ, not 2 * SIZE_SZ as for + regular mmapped chunks. */ + if (bytes > oldsize - SIZE_SZ) + bytes = oldsize - SIZE_SZ; memcpy (newmem, oldmem, bytes); return newmem; } |