memory leak in free()

Hello,

This simple code demonstrates the problem:

int main ()
{
    char* buffer1;
    char* buffer2;
    int size = 2*1024*1024 + 1;

for(;;) {
        buffer1 = (char *) malloc(size);
        buffer2 = (char *) malloc(size);

        free(buffer1);
        free(buffer2);
 }
}

The second free() does not free allocated memory if size >2Mb.

On 6.1-STABLE all is OK.

Best Regards