Fix clib_bitmap_next_clear() function when no clear bits left

If the bitmap has no bit clear after the input bit position i,
the function will return i even if its bit is set.
Fix is to return the next bit just beyond the free bitmap.

This can cause IP neighbor scan crash in ip_neighbor_scan() with
a debug image. With production image, ip_neighbor_scan() may still
function, AFAICT, with extra neighbor delete attempts for entries
already deleted, until these entries are reused for new neighbors.

Change-Id: If6422ef6f63908ea39651de4ccbd8cb0b294bd69
Signed-off-by: John Lo <loj@cisco.com>

diff --git a/src/vppinfra/bitmap.h b/src/vppinfra/bitmap.h
index d6dfe86..0e94d02 100644 (file)
--- a/src/vppinfra/bitmap.h
+++ b/src/vppinfra/bitmap.h
@@ -728,6 +728,9 @@ clib_bitmap_next_clear (uword * ai, uword i)
          if (t)
            return log2_first_set (t) + i0 * BITS (ai[0]);
        }
+
+      /* no clear bit left in bitmap, return bit just beyond bitmap */
+      return (i0 + 1) * BITS (ai[0]);
     }
   return i;
 }