From: Alexander Lobakin <alobakin@pm.me>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>
Cc: Alexander Lobakin <alobakin@pm.me>,
Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
Song Liu <songliubraving@fb.com>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v2 bpf 11/11] samples/bpf: xdpsock: fix -Wmaybe-uninitialized
Date: Thu, 21 Apr 2022 00:39:57 +0000 [thread overview]
Message-ID: <20220421003152.339542-12-alobakin@pm.me> (raw)
In-Reply-To: <20220421003152.339542-1-alobakin@pm.me>
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 uninitialized in this function [-Wmaybe-uninitialized]
1531 | pktgen_hdr->tv_usec = 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 uninitialized in this function [-Wmaybe-uninitialized]
1530 | pktgen_hdr->tv_sec = 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 == true and
they're being used also only when @opt_tstamp == 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 operation")
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
---
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 9747d47a0a8f..a6d8291c8b38 100644
--- a/samples/bpf/xdpsock_user.c
+++ b/samples/bpf/xdpsock_user.c
@@ -1497,7 +1497,7 @@ static void rx_drop_all(void)
static int tx_only(struct xsk_socket_info *xsk, u32 *frame_nb,
int batch_size, unsigned long tx_ns)
{
- u32 idx, tv_sec, tv_usec;
+ u32 idx, tv_sec = 0, tv_usec = 0;
unsigned int i;
while (xsk_ring_prod__reserve(&xsk->tx, batch_size, &idx) <
--
2.36.0
next prev parent reply other threads:[~2022-04-21 0:40 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-21 0:38 [PATCH v2 bpf 00/11] bpf: random unpopular userspace fixes (32 bit et al) Alexander Lobakin
2022-04-21 0:38 ` [PATCH v2 bpf 01/11] bpftool: use a local copy of perf_event to fix accessing ::bpf_cookie Alexander Lobakin
2022-04-21 0:38 ` [PATCH v2 bpf 02/11] bpftool: define a local bpf_perf_link to fix accessing its fields Alexander Lobakin
2023-04-14 9:54 ` Michal Suchánek
2023-04-14 15:18 ` Alexander Lobakin
2023-04-14 16:28 ` Michal Suchánek
2023-04-20 23:07 ` Andrii Nakryiko
2023-04-21 7:39 ` Michal Suchánek
2023-05-03 23:43 ` Quentin Monnet
2023-05-03 23:52 ` Andrii Nakryiko
2023-05-04 8:18 ` Michal Suchánek
2023-05-04 16:48 ` Yonghong Song
2022-04-21 0:39 ` [PATCH v2 bpf 03/11] bpftool: use a local bpf_perf_event_value " Alexander Lobakin
2023-06-06 21:02 ` Nick Desaulniers
2023-06-07 10:42 ` Quentin Monnet
2023-06-07 16:18 ` Alexander Lobakin
2022-04-21 0:39 ` [PATCH v2 bpf 04/11] bpftool: fix fcntl.h include Alexander Lobakin
2022-04-21 0:39 ` [PATCH v2 bpf 05/11] samples/bpf: add 'asm/mach-generic' include path for every MIPS Alexander Lobakin
2022-04-21 0:39 ` [PATCH v2 bpf 06/11] samples/bpf: use host bpftool to generate vmlinux.h, not target Alexander Lobakin
2022-04-21 0:39 ` [PATCH v2 bpf 07/11] samples/bpf: fix uin64_t format literals Alexander Lobakin
2022-04-21 7:46 ` David Laight
2022-04-21 22:55 ` Alexander Lobakin
2022-04-21 0:39 ` [PATCH v2 bpf 08/11] samples/bpf: fix false-positive right-shift underflow warnings Alexander Lobakin
2022-04-21 0:39 ` [PATCH v2 bpf 09/11] samples/bpf: fix include order for non-Glibc environments Alexander Lobakin
2022-04-21 0:39 ` [PATCH v2 bpf 10/11] samples/bpf: fix -Wsequence-point Alexander Lobakin
2022-04-21 0:39 ` Alexander Lobakin [this message]
2022-04-21 0:40 ` [PATCH v2 bpf 00/11] bpf: random unpopular userspace fixes (32 bit et al) Alexei Starovoitov
2022-04-21 10:52 ` Toke Høiland-Jørgensen
2022-04-21 22:39 ` Alexander Lobakin
2022-04-21 23:17 ` Toke Høiland-Jørgensen
2022-05-03 21:17 ` Alexander Lobakin
2022-05-04 11:34 ` Toke Høiland-Jørgensen
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