src/core/ngx_slab.c:629: error: Integer Overflow L2
  ([0, `pool->pages->slab`] - 1):unsigned64 by call to `ngx_slab_free_pages`.

src/core/ngx_slab.c:451:1: Parameter `pool->pages->slab`
449. 
450. 
451. void
     ^
452. ngx_slab_free_locked(ngx_slab_pool_t *pool, void *p)
453. {

src/core/ngx_slab.c:468:5: Assignment
466.     n = ((u_char *) p - pool->start) >> ngx_pagesize_shift;
467.     page = &pool->pages[n];
468.     slab = page->slab;
         ^
469.     type = ngx_slab_page_type(page);
470. 

src/core/ngx_slab.c:627:9: Assignment
625. 
626.         n = ((u_char *) p - pool->start) >> ngx_pagesize_shift;
627.         size = slab & ~NGX_SLAB_PAGE_START;
             ^
628. 
629.         ngx_slab_free_pages(pool, &pool->pages[n], size);

src/core/ngx_slab.c:629:9: Call
627.         size = slab & ~NGX_SLAB_PAGE_START;
628. 
629.         ngx_slab_free_pages(pool, &pool->pages[n], size);
             ^
630. 
631.         ngx_slab_junk(p, size << ngx_pagesize_shift);

src/core/ngx_slab.c:722:1: <LHS trace>
720. 
721. 
722. static void
     ^
723. ngx_slab_free_pages(ngx_slab_pool_t *pool, ngx_slab_page_t *page,
724.     ngx_uint_t pages)

src/core/ngx_slab.c:722:1: Parameter `pages`
  720. 
  721. 
  722. static void
       ^
  723. ngx_slab_free_pages(ngx_slab_pool_t *pool, ngx_slab_page_t *page,
  724.     ngx_uint_t pages)

src/core/ngx_slab.c:730:18: Binary operation: ([0, pool->pages->slab] - 1):unsigned64 by call to `ngx_slab_free_pages` 
  728.     pool->pfree += pages;
  729. 
  730.     page->slab = pages--;
                        ^
  731. 
  732.     if (pages) {
