From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9B3983A0E8D; Sat, 17 Oct 2026 16:26:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792254402; cv=none; b=c+Xq8YqExeS1O0o50FHLu6SqlHuLDI1ALym7i6OVM4qAdIHzOjryo1TTryY8F7qkomngGnE+nyc6ewtyeb04Darf4nMbe9gryVKYDzmwB/0xt4lCgEjgoXfn8dGREeFvjFAZ2ZMSMvAq44VBdccWKm9BbkI+1wb4aFDO99Rg9y4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792254402; c=relaxed/simple; bh=d+EoBUdl8Q0EfskMo10hP8ZmntKCZOhoCg7H11h0ZtU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CoJRt593IUBpev1rvyMPDyxWZGaV4E5eeMWS43WotcIj52i+R8jf14Y6bD59D8UB+HFNRxX2S18Lk6vnM+B7/XoZPq4HcRFtlFchfXQu/mWGM9LyWAIjmjoGjuKXMogvtSobsu3wvN3/z8lDDfxQsYx5yKZUcHVF/A6/rZ0GU40= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hQZ4tLGj; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="hQZ4tLGj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EBC8D1F000C4; Sat, 17 Oct 2026 16:26:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792254400; bh=A3frBZ4O8jssgFEWJzBkHg9ls29oZQmWn9W7VmuLUCs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hQZ4tLGjJzbeQZZe5TP3xd9IHAgLUR/FM7jMA+yrrTexU0UzFp+nA9iRf/zGHjStD oJaqFzDq0EOSm51MlGaGfIQjpeWEmzyd0YEgsk1DGnxMH1DfnjVJWFDDSJKzjLYp+n luc+StU1syzRPdYA2ptffYShU2yzuhy14IIofJkg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Feng Liu , Eran Ben Elisha , Cosmin Ratiu , Nimrod Oren , Tariq Toukan , Paolo Abeni , Sasha Levin Subject: [PATCH 6.12 435/869] net/mlx5e: Fix publication race for priv->channel_stats[] Date: Sat, 17 Oct 2026 17:54:36 +0200 Message-ID: <20261017160048.295138556@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160036.979869304@linuxfoundation.org> References: <20261017160036.979869304@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Feng Liu [ Upstream commit 5a799714e8ca0bce9ea40694f49914cf1adbbaa9 ] mlx5e_channel_stats_alloc() publishes a new entry to priv->channel_stats[] and then increments priv->stats_nch as a publication token, but neither store carries any memory barrier: priv->channel_stats[ix] = kvzalloc_node(...); if (!priv->channel_stats[ix]) return -ENOMEM; priv->stats_nch++; Concurrent readers compute the loop bound from priv->stats_nch and then dereference priv->channel_stats[i] using plain accesses, e.g. for (i = 0; i < priv->stats_nch; i++) { struct mlx5e_channel_stats *cs = priv->channel_stats[i]; ... cs->rq.packets ... } On weakly-ordered architectures (ARM, PowerPC, RISC-V) the writes to channel_stats[ix] and stats_nch may become visible to other CPUs out of program order. A reader can observe stats_nch == N while still seeing channel_stats[N-1] == NULL, leading to a NULL pointer dereference in the channel_stats loop. This has been observed in production on BlueField-3 DPUs (arm64), where ovs-vswitchd queries netdev statistics over netlink during NIC bringup, racing mlx5e_open_channel() -> mlx5e_channel_stats_alloc() on another CPU: Unable to handle kernel NULL pointer dereference at virtual address 0x840 Hardware name: BlueField-3 DPU pc : mlx5e_fold_sw_stats64+0x30/0x180 [mlx5_core] Call trace: mlx5e_fold_sw_stats64+0x30/0x180 [mlx5_core] dev_get_stats+0x50/0xc0 ovs_vport_get_stats+0x38/0xac [openvswitch] ovs_vport_cmd_fill_info+0x194/0x290 [openvswitch] ovs_vport_cmd_get+0xbc/0x10c [openvswitch] genl_family_rcv_msg_doit+0xd0/0x160 genl_rcv_msg+0xec/0x1f0 netlink_rcv_skb+0x64/0x130 genl_rcv+0x40/0x60 netlink_unicast+0x2fc/0x370 netlink_sendmsg+0x1dc/0x454 ... __arm64_sys_sendmsg+0x2c/0x40 Add mlx5e_stats_nch_write() and mlx5e_stats_nch_read() helpers in en.h that wrap the smp_store_release()/smp_load_acquire() pair on stats_nch. The release/acquire pair establishes the contract: stats_nch == N => channel_stats[0..N-1] are visible and non-NULL. Publish the stats_nch increment via mlx5e_stats_nch_write() in the writer (mlx5e_channel_stats_alloc()), and read stats_nch via mlx5e_stats_nch_read() in all readers: mlx5e RX/TX queue stats, mlx5e_get_base_stats(), ethtool channels stats, IPoIB stats, the sw_stats fold and the HV VHCA stats agent. Fixes: fa691d0c9c08 ("net/mlx5e: Allocate per-channel stats dynamically at first usage") Signed-off-by: Feng Liu Reviewed-by: Eran Ben Elisha Reviewed-by: Cosmin Ratiu Reviewed-by: Nimrod Oren Signed-off-by: Tariq Toukan Link: https://patch.msgid.link/20260630115151.729219-4-tariqt@nvidia.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- drivers/net/ethernet/mellanox/mlx5/core/en.h | 12 ++++++++++++ .../ethernet/mellanox/mlx5/core/en/hv_vhca_stats.c | 10 ++++++---- drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 14 ++++++++------ drivers/net/ethernet/mellanox/mlx5/core/en_stats.c | 9 +++++---- .../net/ethernet/mellanox/mlx5/core/ipoib/ipoib.c | 3 ++- 5 files changed, 33 insertions(+), 15 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h index a0a9a11b0fb92..d9541cfd65152 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h @@ -947,6 +947,18 @@ struct mlx5e_priv { struct mlx5_devcom_comp_dev *devcom; }; +static inline u16 mlx5e_stats_nch_read(const struct mlx5e_priv *priv) +{ + /* Pairs with smp_store_release in mlx5e_stats_nch_write(). */ + return smp_load_acquire(&priv->stats_nch); +} + +static inline void mlx5e_stats_nch_write(struct mlx5e_priv *priv, u16 n) +{ + /* Pairs with smp_load_acquire in mlx5e_stats_nch_read(). */ + smp_store_release(&priv->stats_nch, n); +} + struct mlx5e_dev { struct net_device *netdev; struct devlink_port dl_port; diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/hv_vhca_stats.c b/drivers/net/ethernet/mellanox/mlx5/core/en/hv_vhca_stats.c index 1856d211339f2..adfb49ff42aa9 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/hv_vhca_stats.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/hv_vhca_stats.c @@ -33,9 +33,10 @@ mlx5e_hv_vhca_fill_ring_stats(struct mlx5e_priv *priv, int ch, static void mlx5e_hv_vhca_fill_stats(struct mlx5e_priv *priv, void *data, int buf_len) { + u16 nch = mlx5e_stats_nch_read(priv); int ch, i = 0; - for (ch = 0; ch < priv->stats_nch; ch++) { + for (ch = 0; ch < nch; ch++) { void *buf = data + i; if (WARN_ON_ONCE(buf + @@ -50,8 +51,9 @@ static void mlx5e_hv_vhca_fill_stats(struct mlx5e_priv *priv, void *data, static int mlx5e_hv_vhca_stats_buf_size(struct mlx5e_priv *priv) { - return (sizeof(struct mlx5e_hv_vhca_per_ring_stats) * - priv->stats_nch); + u16 nch = mlx5e_stats_nch_read(priv); + + return sizeof(struct mlx5e_hv_vhca_per_ring_stats) * nch; } static int mlx5e_hv_vhca_stats_buf_max_size(struct mlx5e_priv *priv) @@ -106,7 +108,7 @@ static void mlx5e_hv_vhca_stats_control(struct mlx5_hv_vhca_agent *agent, sagent = &priv->stats_agent; block->version = MLX5_HV_VHCA_STATS_VERSION; - block->rings = priv->stats_nch; + block->rings = mlx5e_stats_nch_read(priv); if (!block->command) { cancel_delayed_work_sync(&priv->stats_agent.work); diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c index f6c15fce4a025..fd3cf53ff17a9 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -2605,7 +2605,7 @@ static int mlx5e_channel_stats_alloc(struct mlx5e_priv *priv, int ix, int cpu) GFP_KERNEL, cpu_to_node(cpu)); if (!priv->channel_stats[ix]) return -ENOMEM; - priv->stats_nch++; + mlx5e_stats_nch_write(priv, priv->stats_nch + 1); return 0; } @@ -3822,9 +3822,10 @@ static int mlx5e_setup_tc(struct net_device *dev, enum tc_setup_type type, void mlx5e_fold_sw_stats64(struct mlx5e_priv *priv, struct rtnl_link_stats64 *s) { + u16 nch = mlx5e_stats_nch_read(priv); int i; - for (i = 0; i < priv->stats_nch; i++) { + for (i = 0; i < nch; i++) { struct mlx5e_channel_stats *channel_stats = priv->channel_stats[i]; struct mlx5e_rq_stats *xskrq_stats = &channel_stats->xskrq; struct mlx5e_rq_stats *rq_stats = &channel_stats->rq; @@ -5290,7 +5291,7 @@ static void mlx5e_get_queue_stats_rx(struct net_device *dev, int i, struct mlx5e_rq_stats *rq_stats; ASSERT_RTNL(); - if (mlx5e_is_uplink_rep(priv) || !priv->stats_nch) + if (mlx5e_is_uplink_rep(priv) || !mlx5e_stats_nch_read(priv)) return; channel_stats = priv->channel_stats[i]; @@ -5310,7 +5311,7 @@ static void mlx5e_get_queue_stats_tx(struct net_device *dev, int i, struct mlx5e_sq_stats *sq_stats; ASSERT_RTNL(); - if (!priv->stats_nch) + if (!mlx5e_stats_nch_read(priv)) return; /* no special case needed for ptp htb etc since txq2sq_stats is kept up @@ -5327,6 +5328,7 @@ static void mlx5e_get_base_stats(struct net_device *dev, struct netdev_queue_stats_tx *tx) { struct mlx5e_priv *priv = netdev_priv(dev); + u16 nch = mlx5e_stats_nch_read(priv); struct mlx5e_ptp *ptp_channel; int i, tc; @@ -5336,7 +5338,7 @@ static void mlx5e_get_base_stats(struct net_device *dev, rx->bytes = 0; rx->alloc_fail = 0; - for (i = priv->channels.params.num_channels; i < priv->stats_nch; i++) { + for (i = priv->channels.params.num_channels; i < nch; i++) { struct netdev_queue_stats_rx rx_i = {0}; mlx5e_get_queue_stats_rx(dev, i, &rx_i); @@ -5361,7 +5363,7 @@ static void mlx5e_get_base_stats(struct net_device *dev, tx->packets = 0; tx->bytes = 0; - for (i = 0; i < priv->stats_nch; i++) { + for (i = 0; i < nch; i++) { struct mlx5e_channel_stats *channel_stats = priv->channel_stats[i]; /* handle two cases: diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c index 2f077ad1e810b..652cae2feb013 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c @@ -528,6 +528,7 @@ static void mlx5e_stats_update_stats_rq_page_pool(struct mlx5e_channel *c) static MLX5E_DECLARE_STATS_GRP_OP_UPDATE_STATS(sw) { struct mlx5e_sw_stats *s = &priv->stats.sw; + u16 nch = mlx5e_stats_nch_read(priv); int i; memset(s, 0, sizeof(*s)); @@ -535,7 +536,7 @@ static MLX5E_DECLARE_STATS_GRP_OP_UPDATE_STATS(sw) for (i = 0; i < priv->channels.num; i++) /* for active channels only */ mlx5e_stats_update_stats_rq_page_pool(priv->channels.c[i]); - for (i = 0; i < priv->stats_nch; i++) { + for (i = 0; i < nch; i++) { struct mlx5e_channel_stats *channel_stats = priv->channel_stats[i]; @@ -2438,7 +2439,7 @@ static MLX5E_DECLARE_STATS_GRP_OP_UPDATE_STATS(ptp) { return; } static MLX5E_DECLARE_STATS_GRP_OP_NUM_STATS(channels) { - int max_nch = priv->stats_nch; + int max_nch = mlx5e_stats_nch_read(priv); return (NUM_RQ_STATS * max_nch) + (NUM_CH_STATS * max_nch) + @@ -2451,8 +2452,8 @@ static MLX5E_DECLARE_STATS_GRP_OP_NUM_STATS(channels) static MLX5E_DECLARE_STATS_GRP_OP_FILL_STRS(channels) { + int max_nch = mlx5e_stats_nch_read(priv); bool is_xsk = priv->xsk.ever_used; - int max_nch = priv->stats_nch; int i, j, tc; for (i = 0; i < max_nch; i++) @@ -2484,8 +2485,8 @@ static MLX5E_DECLARE_STATS_GRP_OP_FILL_STRS(channels) static MLX5E_DECLARE_STATS_GRP_OP_FILL_STATS(channels) { + int max_nch = mlx5e_stats_nch_read(priv); bool is_xsk = priv->xsk.ever_used; - int max_nch = priv->stats_nch; int i, j, tc; for (i = 0; i < max_nch; i++) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/ipoib/ipoib.c b/drivers/net/ethernet/mellanox/mlx5/core/ipoib/ipoib.c index 0979d672d47f3..2c71e2ac40c59 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/ipoib/ipoib.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/ipoib/ipoib.c @@ -114,10 +114,11 @@ void mlx5i_cleanup(struct mlx5e_priv *priv) static void mlx5i_grp_sw_update_stats(struct mlx5e_priv *priv) { + u16 nch = mlx5e_stats_nch_read(priv); struct rtnl_link_stats64 s = {}; int i, j; - for (i = 0; i < priv->stats_nch; i++) { + for (i = 0; i < nch; i++) { struct mlx5e_channel_stats *channel_stats; struct mlx5e_rq_stats *rq_stats; -- 2.53.0