From: Stephen Hemminger <stephen@networkplumber.org>
To: dev@dpdk.org
Cc: stable@dpdk.org, Dariusz Sosnowski <dsosnowski@nvidia.com>,
Viacheslav Ovsiienko <viacheslavo@nvidia.com>,
Bing Zhao <bingz@nvidia.com>, Ori Kam <orika@nvidia.com>,
Suanming Mou <suanmingm@nvidia.com>,
Matan Azrad <matan@nvidia.com>, Ophir Munk <ophirmu@nvidia.com>
Subject: Re: [PATCH] net/mlx5: fix uninitialized warning
Date: Thu, 13 Nov 2025 09:50:49 -0800 [thread overview]
Message-ID: <20251113095049.008bbf9b@phoenix> (raw)
In-Reply-To: <20251113163301.285550-1-stephen@networkplumber.org>
On Thu, 13 Nov 2025 08:33:01 -0800
Stephen Hemminger <stephen@networkplumber.org> wrote:
> Gcc-16 detects use of uninitialized variable.
> ./drivers/net/mlx5/linux/mlx5_ethdev_os.c: In function ‘mlx5_link_update’:
> ../drivers/net/mlx5/linux/mlx5_ethdev_os.c:539:15: warning: ‘*(long unsigned int *)((char *)&dev_link + offsetof(struct rte_eth_link, <U38c0>))’ may be used uninitialized [-Wmaybe-uninitialized]
> 539 | ret = !!memcmp(&dev->data->dev_link, &dev_link,
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 540 | sizeof(struct rte_eth_link));
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../drivers/net/mlx5/linux/mlx5_ethdev_os.c:515:29: note: ‘*(long unsigned int *)((char *)&dev_link + offsetof(struct rte_eth_link, <U38c0>))’ was declared here
> 515 | struct rte_eth_link dev_link;
> |
>
> If the retry loop exits the code would do memcmp against unintialized
> stack value. Resolve by intializing to zero.
>
> Fixes: 1256805dd54d ("net/mlx5: move Linux-specific functions")
> Cc: stable@dpdk.org
>
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> ---
The build fails with clang because of the (annoying) use of pedantic in this driver.
I will let mlx5 maintainers fix it then.
../drivers/net/mlx5/linux/mlx5_ethdev_os.c:515:33: error: use of GNU empty initializer extension [-Werror,-Wgnu-empty-initializer]
struct rte_eth_link dev_link = { };
prev parent reply other threads:[~2025-11-13 17:50 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-13 16:33 Stephen Hemminger
2025-11-13 17:50 ` Stephen Hemminger [this message]
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