From: Jianbo Liu The function mlx5_uplink_netdev_get() gets the uplink netdevice pointer from mdev->mlx5e_res.uplink_netdev. However, the netdevice can be removed and its pointer cleared when unbound from the mlx5_core.eth driver. This results in a NULL pointer, causing a kernel panic. BUG: unable to handle page fault for address: 0000000000001300 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP CPU: 5 UID: 0 PID: 1420 Comm: devlink Not tainted 6.16.0-rc7+ #1 NONE Hardware name: ... RIP: 0010:mlx5e_vport_rep_load+0x22a/0x270 [mlx5_core] Code: ... RSP: 0018:ffff8881142b78f0 EFLAGS: 00010246 RAX: ffff888104652150 RBX: ffff88810215a6c0 RCX: 0000000000000000 RDX: ffff888104652000 RSI: ffffffffa02b0cc0 RDI: 0000000000000000 RBP: ffff888104652000 R08: ffff8884edaad5c0 R09: 0000000000000000 R10: ffff8881142b78f0 R11: ffff888100716480 R12: ffff88810f1e0000 R13: ffff88810215a6c0 R14: ffff888104652000 R15: ffff8881095301a0 FS: 00007fa008742740(0000) GS:ffff88856a9f6000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000001300 CR3: 0000000106fb6001 CR4: 0000000000372eb0 Call Trace: mlx5_esw_offloads_rep_load+0x68/0xe0 [mlx5_core] esw_offloads_enable+0x593/0x910 [mlx5_core] mlx5_eswitch_enable_locked+0x341/0x420 [mlx5_core] ? is_mp_supported+0x4b/0xa0 [mlx5_core] mlx5_devlink_eswitch_mode_set+0x17e/0x3a0 [mlx5_core] devlink_nl_eswitch_set_doit+0x60/0xd0 genl_family_rcv_msg_doit+0xe0/0x130 genl_rcv_msg+0x183/0x290 ? devlink_get_from_attrs_lock+0x180/0x180 ? devlink_nl_eswitch_get_doit+0x290/0x290 ? devlink_nl_pre_doit_port_optional+0x40/0x40 ? genl_family_rcv_msg_dumpit+0xf0/0xf0 netlink_rcv_skb+0x4b/0xf0 genl_rcv+0x24/0x40 netlink_unicast+0x255/0x380 ? __alloc_skb+0x120/0x1b0 netlink_sendmsg+0x1f3/0x420 __sock_sendmsg+0x38/0x60 __sys_sendto+0x119/0x180 ? count_memcg_events+0xec/0x150 ? __rseq_handle_notify_resume+0xa9/0x460 ? handle_mm_fault+0x12e/0x260 ? do_user_addr_fault+0x2a4/0x680 __x64_sys_sendto+0x20/0x30 do_syscall_64+0x53/0x1d0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Ensure the pointer is valid before use by checking it for NULL. If it is valid, immediately call netdev_hold() to take a reference, and preventing the netdevice from being freed while it is in use. Fixes: 7a9fb35e8c3a ("net/mlx5e: Do not reload ethernet ports when changing eswitch mode") Signed-off-by: Jianbo Liu Reviewed-by: Cosmin Ratiu Reviewed-by: Jiri Pirko Reviewed-by: Dragos Tatulea Signed-off-by: Tariq Toukan --- .../net/ethernet/mellanox/mlx5/core/en_rep.c | 26 +++++++++++++++---- .../net/ethernet/mellanox/mlx5/core/esw/qos.c | 1 + .../ethernet/mellanox/mlx5/core/lib/mlx5.h | 15 ++++++++++- include/linux/mlx5/driver.h | 1 + 4 files changed, 37 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c index 63a7a788fb0d..912887376824 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c @@ -1506,12 +1506,20 @@ static const struct mlx5e_profile mlx5e_uplink_rep_profile = { static int mlx5e_vport_uplink_rep_load(struct mlx5_core_dev *dev, struct mlx5_eswitch_rep *rep) { - struct mlx5e_priv *priv = netdev_priv(mlx5_uplink_netdev_get(dev)); struct mlx5e_rep_priv *rpriv = mlx5e_rep_to_rep_priv(rep); + struct net_device *netdev = mlx5_uplink_netdev_get(dev); + struct mlx5e_priv *priv; + int err; + + if (!netdev) + return 0; + priv = netdev_priv(netdev); rpriv->netdev = priv->netdev; - return mlx5e_netdev_change_profile(priv, &mlx5e_uplink_rep_profile, - rpriv); + err = mlx5e_netdev_change_profile(priv, &mlx5e_uplink_rep_profile, + rpriv); + mlx5_uplink_netdev_put(dev, netdev); + return err; } static void @@ -1638,8 +1646,16 @@ mlx5e_vport_rep_unload(struct mlx5_eswitch_rep *rep) { struct mlx5e_rep_priv *rpriv = mlx5e_rep_to_rep_priv(rep); struct net_device *netdev = rpriv->netdev; - struct mlx5e_priv *priv = netdev_priv(netdev); - void *ppriv = priv->ppriv; + struct mlx5e_priv *priv; + void *ppriv; + + if (!netdev) { + ppriv = rpriv; + goto free_ppriv; + } + + priv = netdev_priv(netdev); + ppriv = priv->ppriv; if (rep->vport == MLX5_VPORT_UPLINK) { mlx5e_vport_uplink_rep_unload(rpriv); diff --git a/drivers/net/ethernet/mellanox/mlx5/core/esw/qos.c b/drivers/net/ethernet/mellanox/mlx5/core/esw/qos.c index 8b4977650183..5f2d6c35f1ad 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/esw/qos.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/esw/qos.c @@ -1515,6 +1515,7 @@ static u32 mlx5_esw_qos_lag_link_speed_get_locked(struct mlx5_core_dev *mdev) speed = lksettings.base.speed; out: + mlx5_uplink_netdev_put(mdev, slave); return speed; } diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/mlx5.h b/drivers/net/ethernet/mellanox/mlx5/core/lib/mlx5.h index b111ccd03b02..74ea5da58b7e 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/mlx5.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/mlx5.h @@ -47,7 +47,20 @@ int mlx5_crdump_collect(struct mlx5_core_dev *dev, u32 *cr_data); static inline struct net_device *mlx5_uplink_netdev_get(struct mlx5_core_dev *mdev) { - return mdev->mlx5e_res.uplink_netdev; + struct mlx5e_resources *mlx5e_res = &mdev->mlx5e_res; + struct net_device *netdev; + + mutex_lock(&mlx5e_res->uplink_netdev_lock); + netdev = mlx5e_res->uplink_netdev; + netdev_hold(netdev, &mlx5e_res->tracker, GFP_KERNEL); + mutex_unlock(&mlx5e_res->uplink_netdev_lock); + return netdev; +} + +static inline void mlx5_uplink_netdev_put(struct mlx5_core_dev *mdev, + struct net_device *netdev) +{ + netdev_put(netdev, &mdev->mlx5e_res.tracker); } struct mlx5_sd; diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h index 8c5fbfb85749..10fe492e1fed 100644 --- a/include/linux/mlx5/driver.h +++ b/include/linux/mlx5/driver.h @@ -663,6 +663,7 @@ struct mlx5e_resources { bool tisn_valid; } hw_objs; struct net_device *uplink_netdev; + netdevice_tracker tracker; struct mutex uplink_netdev_lock; struct mlx5_crypto_dek_priv *dek_priv; }; -- 2.31.1