From: Stanislav Fomichev <stfomichev@gmail.com>
To: Cosmin Ratiu <cratiu@nvidia.com>
Cc: netdev@vger.kernel.org, "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
Stanislav Fomichev <sdf@fomichev.me>,
Mina Almasry <almasrymina@google.com>,
Saeed Mahameed <saeedm@nvidia.com>,
Tariq Toukan <tariqt@nvidia.com>,
Dragos Tatulea <dtatulea@nvidia.com>
Subject: Re: [PATCH net v3] net: Lock lower level devices when updating features
Date: Fri, 9 May 2025 08:04:44 -0700 [thread overview]
Message-ID: <aB4ZjJDLYEJnqGGH@mini-arch> (raw)
In-Reply-To: <20250509072850.2002821-1-cratiu@nvidia.com>
On 05/09, Cosmin Ratiu wrote:
> __netdev_update_features() expects the netdevice to be ops-locked, but
> it gets called recursively on the lower level netdevices to sync their
> features, and nothing locks those.
>
> This commit fixes that, with the assumption that it shouldn't be possible
> for both higher-level and lover-level netdevices to require the instance
> lock, because that would lead to lock dependency warnings.
>
> Without this, playing with higher level (e.g. vxlan) netdevices on top
> of netdevices with instance locking enabled can run into issues:
>
> WARNING: CPU: 59 PID: 206496 at ./include/net/netdev_lock.h:17 netif_napi_add_weight_locked+0x753/0xa60
> [...]
> Call Trace:
> <TASK>
> mlx5e_open_channel+0xc09/0x3740 [mlx5_core]
> mlx5e_open_channels+0x1f0/0x770 [mlx5_core]
> mlx5e_safe_switch_params+0x1b5/0x2e0 [mlx5_core]
> set_feature_lro+0x1c2/0x330 [mlx5_core]
> mlx5e_handle_feature+0xc8/0x140 [mlx5_core]
> mlx5e_set_features+0x233/0x2e0 [mlx5_core]
> __netdev_update_features+0x5be/0x1670
> __netdev_update_features+0x71f/0x1670
> dev_ethtool+0x21c5/0x4aa0
> dev_ioctl+0x438/0xae0
> sock_ioctl+0x2ba/0x690
> __x64_sys_ioctl+0xa78/0x1700
> do_syscall_64+0x6d/0x140
> entry_SYSCALL_64_after_hwframe+0x4b/0x53
> </TASK>
>
> Fixes: 7e4d784f5810 ("net: hold netdev instance lock during rtnetlink operations")
> Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
next prev parent reply other threads:[~2025-05-09 15:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-09 7:28 [PATCH net v3] net: Lock lower level devices when updating features Cosmin Ratiu
2025-05-09 15:04 ` Stanislav Fomichev [this message]
2025-05-13 2:00 ` patchwork-bot+netdevbpf
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