From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-4322.protonmail.ch (mail-4322.protonmail.ch [185.70.43.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9F5E13234 for ; Thu, 14 Apr 2022 22:47:33 +0000 (UTC) Date: Thu, 14 Apr 2022 22:47:20 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pm.me; s=protonmail2; t=1649976451; bh=wBk9JjddsWdkPL3+TnZwqvhbFqPlgDryFkVFtACVs5s=; h=Date:To:From:Cc:Reply-To:Subject:Message-ID:In-Reply-To: References:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID; b=nOwFrCMQqgdnT5ACg0miHsryQvMGaVe1VVs6T+wkBBVk40W6TE0Oxjlsqbiiqtd4i IL3o3iY4Fmhszf3elBnEFfupsT+BLDg2f0H4qXtRtsemsQkLk8jIQ9ZubVi6/8Mj0C WSO0kpOQNupTzmMubOERMBBZKtgMtH9nko71yWrOKqgqTgLI6YoUgUiUMxyn77ZNzn B4gmE8cw6m7FaO8iBFxmb5lmu/zAbxSCDY+JMXFJ2mue0BKKsVwYAGHThryC4JPvB7 hqVfIWqC1Bv4OFOZY6FypF77uCtCS32X6gX/aV7jChafN1KUc8WV9PUzrVlWlFTDd0 50OCb5uCi1WOQ== To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko From: Alexander Lobakin Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , "David S. Miller" , Jakub Kicinski , Jesper Dangaard Brouer , =?utf-8?Q?Bj=C3=B6rn_T=C3=B6pel?= , Magnus Karlsson , Jonathan Lemon , Nathan Chancellor , Nick Desaulniers , Alexander Lobakin , Dmitrii Dolgov <9erthalion6@gmail.com>, Quentin Monnet , Tiezhu Yang , Kumar Kartikeya Dwivedi , Chenbo Feng , Willem de Bruijn , Daniel Wagner , Thomas Graf , Ong Boon Leong , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, llvm@lists.linux.dev Reply-To: Alexander Lobakin Subject: [PATCH bpf-next 11/11] samples: bpf: xdpsock: fix -Wmaybe-uninitialized Message-ID: <20220414223704.341028-12-alobakin@pm.me> In-Reply-To: <20220414223704.341028-1-alobakin@pm.me> References: <20220414223704.341028-1-alobakin@pm.me> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Fix two sort-of-false-positives in the xdpsock userspace part: samples/bpf/xdpsock_user.c: In function 'main': samples/bpf/xdpsock_user.c:1531:47: warning: 'tv_usec' may be used uninitia= lized in this function [-Wmaybe-uninitialized] 1531 | pktgen_hdr->tv_usec =3D htonl(tv_usec); | ^~~~~~~~~~~~~~ samples/bpf/xdpsock_user.c:1500:26: note: 'tv_usec' was declared here 1500 | u32 idx, tv_sec, tv_usec; | ^~~~~~~ samples/bpf/xdpsock_user.c:1530:46: warning: 'tv_sec' may be used uninitial= ized in this function [-Wmaybe-uninitialized] 1530 | pktgen_hdr->tv_sec =3D htonl(tv_sec); | ^~~~~~~~~~~~~ samples/bpf/xdpsock_user.c:1500:18: note: 'tv_sec' was declared here 1500 | u32 idx, tv_sec, tv_usec; | ^~~~~~ Both variables are always initialized when @opt_tstamp =3D=3D true and they're being used also only when @opt_tstamp =3D=3D true. However, that variable comes from the BSS and is being toggled from another function. They can't be executed simultaneously to actually trigger undefined behaviour, but purely technically it is a correct warning. Just initialize them with zeroes. Fixes: eb68db45b747 ("samples/bpf: xdpsock: Add timestamp for Tx-only opera= tion") Signed-off-by: Alexander Lobakin --- samples/bpf/xdpsock_user.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/samples/bpf/xdpsock_user.c b/samples/bpf/xdpsock_user.c index 399b999fcec2..1dc7ad5dbef4 100644 --- a/samples/bpf/xdpsock_user.c +++ b/samples/bpf/xdpsock_user.c @@ -1496,7 +1496,7 @@ static void rx_drop_all(void) static int tx_only(struct xsk_socket_info *xsk, u32 *frame_nb, =09=09 int batch_size, unsigned long tx_ns) { -=09u32 idx, tv_sec, tv_usec; +=09u32 idx, tv_sec =3D 0, tv_usec =3D 0; =09unsigned int i; =09while (xsk_ring_prod__reserve(&xsk->tx, batch_size, &idx) < -- 2.35.2