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From: Dragos Tatulea <dtatulea@nvidia.com>
To: Prathamesh Deshpande <prathameshdeshpande7@gmail.com>,
	Saeed Mahameed <saeedm@nvidia.com>,
	Leon Romanovsky <leon@kernel.org>,
	Tariq Toukan <tariqt@nvidia.com>, Mark Bloch <mbloch@nvidia.com>,
	Andrew Lunn <andrew+netdev@lunn.ch>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@kernel.org>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
Cc: Cosmin Ratiu <cratiu@nvidia.com>,
	Carolina Jubran <cjubran@nvidia.com>,
	Alex Vesker <valex@mellanox.com>,
	Erez Shitrit <erezsh@mellanox.com>,
	netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] net/mlx5: IPOIB, Fix QPN lookup race
Date: Fri, 30 Oct 2026 12:18:59 +0100	[thread overview]
Message-ID: <ade46454-e575-43e4-85aa-eeb5ad79408a@nvidia.com> (raw)
In-Reply-To: <20261030002241.8508-1-prathameshdeshpande7@gmail.com>

On 30.10.26 01:22, Prathamesh Deshpande wrote:
> mlx5i_pkey_get_netdev() reads the QPN hash table without ht_lock,
> while mlx5i_pkey_del_qpn() removes entries under that lock and then
> frees them.
> 
> PKEY child interfaces share the parent's RX resources, so RX lookups
> can overlap child removal and access a freed entry. A lookup for
> another QPN in the same bucket can also be affected.
>
I don't think that all these cases can happen. But I can see how a
CQE completion on the parent can read a pointer from the hash
bucket that just got deleted.

Please improve the commit message.

> Hold ht_lock during lookup and save node->netdev before unlocking.
> 
Holding the spinlock in the datapath is not a good idea. AFAIU
using hlist RCU variants will be enough.

Thanks,
Dragos

  parent reply	other threads:[~2026-10-30 11:19 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-30  0:22 [PATCH net] net/mlx5: IPOIB, Fix QPN lookup race Prathamesh Deshpande
2026-10-30  0:29 ` netdev-bot+sinfo
2026-10-30  0:31 ` sashiko-bot
2026-10-30 11:18 ` Dragos Tatulea [this message]
2026-10-30 18:12   ` Prathamesh Deshpande

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