In 5.6, if the LRU list mutex is held in addition to the flush list mutex, no BUF_BLOCK_REMOVE_HASH pages can be seen on the flush list. This is not the case for buf_do_flush_list_batch(), thus one of its subroutines buf_flush_page_and_try_neighbors() may hit the same issue. Likewise in buf_get_latched_pages_number_instance().
In 5.6, if the LRU list mutex is held in addition to the flush list mutex, no BUF_BLOCK_ REMOVE_ HASH pages can be seen on the flush list. This is not the case for buf_do_ flush_list_ batch() , thus one of its subroutines buf_flush_ page_and_ try_neighbors( ) may hit the same issue. Likewise in buf_get_ latched_ pages_number_ instance( ).