Problem

The server crashes while allocating an index stat,
after 2^20 indexes.

This happens when the index buffer,
of size 1024*1024, is full.

The crash happens in PFS_buffer_scalable_container::allocate(),
while using pages beyond the end of the m_pages[PFS_PAGE_COUNT] array.

The root cause is PFS_buffer_scalable_container::init(),
which can compute a value of m_max_page_count that exceeds PFS_PAGE_COUNT.

Solution

When PFS_buffer_scalable_container::init() is called for a max size
that exceeds the buffer total capacity,
trim down m_max_page_count to PFS_PAGE_COUNT,
as this is the effective max number of pages that can be used.