lib: os: heap-validate: Fix wrong chunkid returned by max_chunkid()

With 64 bytes heap and 1 byte allocation on a big heap, we get:

  0   1   2   3   4   5   6   7
| h | h | b | b | c | 1 | s | f |

where
  - h: chunk0 header
  - b: buckets in chunk0
  - c: chunk header for the first allocation
  - 1: chunk mem
  - s: solo free header
  - f: end marker / footer

max_chunkid() was returning h->end_chunk - min_chunk_size(h), which is
5 because min_chunk_size() on a big heap is 2.  This works if you
don't have the solo free header at 6 and the heap is like:

  0   1   2   3   4   5   6
| h | h | b | b | c | 1 | f |

max_chunkid() in this case gives you 6 - 2 = 4, which is the right
chunkid for the last chunk header.

This commit replaces max_chunkid() with h->end_chunk and "<=" (less
than or equal to) with "<" (less than), so that it always compares
against the end maker chunkid, but the code won't touch the end maker
itself.

Signed-off-by: Yasushi SHOJI <yashi@spacecubics.com>
1 file changed