From: David Marchand <david.marchand@redhat.com>
To: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: dev@dpdk.org, cheng1.jiang@intel.com, chenbo.xia@intel.com,
zhoumin@loongson.cn, stable@dpdk.org,
Thomas Monjalon <thomas@monjalon.net>
Subject: Re: [PATCH] vhost: fix compilation issue in async path
Date: Wed, 5 Oct 2022 16:56:09 +0200 [thread overview]
Message-ID: <CAJFAV8ybX6xCuecz9Qjy9d4y5ZXghnBpZ0TVdB33G_r9j2iA-Q@mail.gmail.com> (raw)
In-Reply-To: <20221005144859.70717-1-maxime.coquelin@redhat.com>
On Wed, Oct 5, 2022 at 4:49 PM Maxime Coquelin
<maxime.coquelin@redhat.com> wrote:
>
> This patch fixes a compilation issue met with GCC on
GCC 12 (it is worth detailing, since I and Thomas hit the same issue
on some other cross compiling toolchains using GCC 12).
> Loongarch64:
LoongArch64
>
> In function ‘mbuf_to_desc’,
> inlined from ‘vhost_enqueue_async_packed’ at ../../../dpdk/lib/vhost/virtio_net.c:1822:6,
> inlined from ‘virtio_dev_rx_async_packed’ at ../../../dpdk/lib/vhost/virtio_net.c:1836:6,
> inlined from ‘virtio_dev_rx_async_submit_packed’ at ../../../dpdk/lib/vhost/virtio_net.c:1895:7:
> ../../../dpdk/lib/vhost/virtio_net.c:1159:18: error: ‘buf_vec[0].buf_addr’ may be used uninitialized [-Werror=maybe-uninitialized]
> 1159 | buf_addr = buf_vec[vec_idx].buf_addr;
> | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../../../dpdk/lib/vhost/virtio_net.c: In function ‘virtio_dev_rx_async_submit_packed’:
> ../../../dpdk/lib/vhost/virtio_net.c:1834:27: note: ‘buf_vec’ declared here
> 1834 | struct buf_vector buf_vec[BUF_VECTOR_MAX];
> | ^~~~~~~
>
> It happens because the compiler assumes that 'size'
> variable in vhost_enqueue_async_packed could wrap to 0 since
> 'size' is uint32_t and pkt->pkt_len too.
>
> In practice, it would never happen since 'pkt->pkt_len' is
> unlikely to be close to UINT32_MAX, but let's just change
> 'size' to uint64_t to make the compiler happy without
> having to add runtime checks.
>
> Fixes: 873e8dad6f49 ("vhost: support packed ring in async datapath")
> Cc: stable@dpdk.org
>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>
--
David Marchand
next prev parent reply other threads:[~2022-10-05 14:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-05 14:48 Maxime Coquelin
2022-10-05 14:56 ` David Marchand [this message]
2022-10-05 15:09 ` Maxime Coquelin
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