- memcpy(dest, shmp_index(handle, shmp(handle, rpages->shmp)->p, offset & (chanb->subbuf_size - 1)), len);
+ src = shmp_index(handle, shmp(handle, rpages->shmp)->p,
+ offset & (chanb->subbuf_size - 1));
+ if (caa_unlikely(!src))
+ return 0;
+ memcpy(dest, src, len);