Hi,
I found out that there seems to be two similar cases in srfi-4.scm (define u32vector-ref (getter-with-setter (lambda (x i) (##core#inline_allocate ("C_a_i_u32vector_ref" 4) x i)) u32vector-set! "(chicken.srfi-4#u32vector-ref v i)")) (define s32vector-ref (getter-with-setter (lambda (x i) (##core#inline_allocate ("C_a_i_s32vector_ref" 4) x i)) s32vector-set! "(chicken.srfi-4#s32vector-ref v))) Since C_a_i_u32vector_ref and C_a_i_s32vector_ref may end up calling bignum1, there should probably be 5 bytes allocated instead of 4. I found this by compiling chicken with gcc -fsanitize=address -fsanitize=aligment, and by linking also related libraries. Address sanitizer then reported potential problems. Jani