[ adding Dan Carpenter ] > On Jun 1, 2023, at 10:33 AM, Dmitry Antipov <dmantipov@xxxxxxxxx> wrote: > > Fix the following warning observed when building 64-bit (actually arm64) > kernel with clang-17 (make LLVM=1 W=1): > > include/linux/sunrpc/xdr.h:779:10: warning: result of comparison of constant > 4611686018427387903 with expression of type '__u32' (aka 'unsigned int') is > always false [-Wtautological-constant-out-of-range-compare] > 779 | if (len > SIZE_MAX / sizeof(*p)) > > That is, an overflow check makes sense for 32-bit kernel only. > > Signed-off-by: Dmitry Antipov <dmantipov@xxxxxxxxx> > --- > include/linux/sunrpc/xdr.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h > index 72014c9216fc..b2d5dc89cf7b 100644 > --- a/include/linux/sunrpc/xdr.h > +++ b/include/linux/sunrpc/xdr.h > @@ -776,7 +776,7 @@ xdr_stream_decode_uint32_array(struct xdr_stream *xdr, > > if (unlikely(xdr_stream_decode_u32(xdr, &len) < 0)) > return -EBADMSG; > - if (len > SIZE_MAX / sizeof(*p)) > + if (unlikely(SIZE_MAX == U32_MAX ? (len > U32_MAX / sizeof(*p)) : 0)) > return -EBADMSG; > p = xdr_inline_decode(xdr, len * sizeof(*p)); > if (unlikely(!p)) > -- > 2.40.1 > -- Chuck Lever
