Unintentional integer overflow

The expression's value may not be what the programmer intended, because the expression is evaluated using a narrow (i.e. few bits) integer type. An integer overflow occurs, with the result converted to a wider integer type
/ext/page_log/palm/palm_kv.c:211: OVERFLOW_BEFORE_WIDEN 174636 Potentially overflowing expression "cache_size_mb * 1048576U" with type "unsigned int" (32 bits, unsigned) is evaluated using 32-bit arithmetic, and then used in a context that expects an expression of type "size_t" (64 bits, unsigned).