From: Jakub Kicinski <kuba@kernel•org>
To: Tariq Toukan <tariqt@nvidia•com>
Cc: Eric Dumazet <edumazet@google•com>,
Paolo Abeni <pabeni@redhat•com>,
Andrew Lunn <andrew+netdev@lunn•ch>,
"David S. Miller" <davem@davemloft•net>,
Saeed Mahameed <saeedm@nvidia•com>,
Leon Romanovsky <leon@kernel•org>, Mark Bloch <mbloch@nvidia•com>,
"Eran Ben Elisha" <eranbe@nvidia•com>,
Feng Liu <feliu@nvidia•com>, Cosmin Ratiu <cratiu@nvidia•com>,
Gal Pressman <gal@nvidia•com>, Simon Horman <horms@kernel•org>,
Alexei Lazar <alazar@nvidia•com>, Nimrod Oren <noren@nvidia•com>,
Carolina Jubran <cjubran@nvidia•com>, Kees Cook <kees@kernel•org>,
Lama Kayal <lkayal@nvidia•com>,
Eran Ben Elisha <eranbe@mellanox•com>,
Saeed Mahameed <saeedm@mellanox•com>,
Haiyang Zhang <haiyangz@microsoft•com>, Joe Damato <joe@dama•to>,
<netdev@vger•kernel.org>, <linux-rdma@vger•kernel.org>,
<linux-kernel@vger•kernel.org>
Subject: Re: [PATCH net 3/4] net/mlx5e: Bounds-check stats_nch in mlx5e_get_queue_stats_rx()
Date: Mon, 8 Jun 2026 18:54:06 -0700 [thread overview]
Message-ID: <20260608185406.6f9ac0bc@kernel.org> (raw)
In-Reply-To: <20260604135041.455754-4-tariqt@nvidia.com>
On Thu, 4 Jun 2026 16:50:40 +0300 Tariq Toukan wrote:
> mlx5e_get_queue_stats_rx() is invoked by the netdev stats core with
> an RX queue index 'i' from real_num_rx_queues. Today it only guards
> against priv->stats_nch == 0 and then dereferences
> priv->channel_stats[i] unconditionally.
>
> During interface bring-up channel_stats[] is populated incrementally
> by mlx5e_channel_stats_alloc(), so a concurrent QSTATS netlink dump
> can call into the helper with i >= stats_nch. The non-zero check
> passes, channel_stats[i] is NULL, and the dereference panics.
>
> Replace the non-zero check with an upper-bound check against
> stats_nch, which subsumes the zero check and prevents the
> out-of-bounds dereference.
I don't think there can be any race here?
The open/close and queue stats readers are under netdev->lock
Your description makes it sound as if we could access half-initialized
state?
Sure, the ndo path is tricky since it's lockless, but please don't
add unnecessary checks in the locked paths.
--
pw-bot: cr
next prev parent reply other threads:[~2026-06-09 1:54 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-04 13:50 [PATCH net 0/4] net/mlx5e: Fix crashes in dynamic per-channel stats and HV VHCA agent Tariq Toukan
2026-06-04 13:50 ` [PATCH net 1/4] net/mlx5e: Fix HV VHCA stats zero-sized buffer allocation Tariq Toukan
2026-06-04 19:24 ` Jacob Keller
2026-06-04 13:50 ` [PATCH net 2/4] net/mlx5e: Fix HV VHCA stats agent registration race Tariq Toukan
2026-06-04 19:25 ` Jacob Keller
2026-06-04 13:50 ` [PATCH net 3/4] net/mlx5e: Bounds-check stats_nch in mlx5e_get_queue_stats_rx() Tariq Toukan
2026-06-04 19:28 ` Jacob Keller
2026-06-09 1:54 ` Jakub Kicinski [this message]
2026-06-04 13:50 ` [PATCH net 4/4] net/mlx5e: Fix publication race for priv->channel_stats[] Tariq Toukan
2026-06-04 19:30 ` Jacob Keller
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