From: Leon Romanovsky <leon@kernel.org>
To: Shuhao Fu <sfual@cse.ust.hk>
Cc: Jason Gunthorpe <jgg@ziepe.ca>,
linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] RDMA/mlx5: Fix refcount inconsistency in mlx5_netdev_event
Date: Mon, 27 Oct 2025 14:59:35 +0200 [thread overview]
Message-ID: <20251027125935.GJ12554@unreal> (raw)
In-Reply-To: <aPe3mnFjQeXaILyR@chcpu18>
On Tue, Oct 21, 2025 at 04:40:58PM +0000, Shuhao Fu wrote:
> Fix refcount inconsistency related to `mlx5_ib_get_native_port_mdev`.
>
> Function `mlx5_ib_get_native_port_mdev` could increase the counter of
> `mpi->mdev_refcnt` if mpi is not master. To ensure refcount consistency,
> each call to `mlx5_ib_get_native_port_mdev` should have a corresponding
> call to `mlx5_ib_put_native_port_mdev`. In `mlx5_netdev_event`, two
> branches fail to do so, leading to a possible bug when unbinding.
>
> Fixes: 379013776222 ("RDMA/mlx5: Handle link status event only for LAG device")
> Fixes: 35b0aa67b298 ("RDMA/mlx5: Refactor netdev affinity code")
> Signed-off-by: Shuhao Fu <sfual@cse.ust.hk>
> ---
> drivers/infiniband/hw/mlx5/main.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
> index fc1e86f6c..0c4aa7c50 100644
> --- a/drivers/infiniband/hw/mlx5/main.c
> +++ b/drivers/infiniband/hw/mlx5/main.c
> @@ -247,7 +247,7 @@ static int mlx5_netdev_event(struct notifier_block *this,
>
> if (!netif_is_lag_master(ndev) && !netif_is_lag_port(ndev) &&
> !mlx5_core_mp_enabled(mdev))
> - return NOTIFY_DONE;
> + goto done;
mdev_refcnt is increased only for MPV slave, but here we are checking if
MPV is enabled. It is not in this leaf and "return NOTIFY_DONE" is the
right thing to do.
>
> if (mlx5_lag_is_roce(mdev) || mlx5_lag_is_sriov(mdev)) {
> struct net_device *lag_ndev;
> @@ -268,7 +268,7 @@ static int mlx5_netdev_event(struct notifier_block *this,
> if (ibdev->is_rep)
> roce = mlx5_get_rep_roce(ibdev, ndev, upper, &port_num);
> if (!roce)
> - return NOTIFY_DONE;
> + goto done;
It is not MPV flow either. There is nothing to change here.
Thanks
>
> ib_ndev = ib_device_get_netdev(&ibdev->ib_dev, port_num);
>
> --
> 2.39.5 (Apple Git-154)
>
prev parent reply other threads:[~2025-10-27 12:59 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-21 16:40 [PATCH] RDMA/mlx5: Fix refcount inconsistency in mlx5_netdev_event Shuhao Fu
2025-10-27 12:59 ` Leon Romanovsky [this message]
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