Subject: [net 01/11] net/mlx5e: Take RTNL lock when needed before calling xdp_set_features()

From: Saeed Mahameed <[email-masked]>
Date: Mon, 7 Aug 2023 14:25:57 -0700

From: Gal Pressman <[email-masked]>

Hold RTNL lock when calling xdp_set_features() with a registered netdev,
as the call triggers the netdev notifiers. This could happen when
switching from uplink rep to nic profile for example.

This resolves the following call trace:

RTNL: assertion failed at net/core/dev.c (1953)
WARNING: CPU: 6 PID: 112670 at net/core/dev.c:1953 call_netdevice_notifiers_info+0x7c/0x80
Modules linked in: sch_mqprio sch_mqprio_lib act_tunnel_key act_mirred act_skbedit cls_matchall nfnetlink_cttimeout act_gact cls_flower sch_ingress bonding ib_umad ip_gre rdma_ucm mlx5_vfio_pci ipip tunnel4 ip6_gre gre mlx5_ib vfio_pci vfio_pci_core vfio_iommu_type1 ib_uverbs vfio mlx5_core ib_ipoib geneve nf_tables ip6_tunnel tunnel6 iptable_raw openvswitch nsh rpcrdma ib_iser libiscsi scsi_transport_iscsi rdma_cm iw_cm ib_cm ib_core xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_nat nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcgss oid_registry overlay zram zsmalloc fuse [last unloaded: ib_uverbs]
CPU: 6 PID: 112670 Comm: devlink Not tainted 6.4.0-rc7_for_upstream_min_debug_2023_06_28_17_02 #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
RIP: 0010:call_netdevice_notifiers_info+0x7c/0x80
Code: 90 ff 80 3d 2d 6b f7 00 00 75 c5 ba a1 07 00 00 48 c7 c6 e4 ce 0b 82 48 c7 c7 c8 f4 04 82 c6 05 11 6b f7 00 01 e8 a4 7c 8e ff <0f> 0b eb a2 0f 1f 44 00 00 55 48 89 e5 41 54 48 83 e4 f0 48 83 ec
RSP: 0018:ffff8882a21c3948 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffffffff82e6f880 RCX: 0000000000000027
RDX: ffff88885f99b5c8 RSI: 0000000000000001 RDI: ffff88885f99b5c0
RBP: 0000000000000028 R08: ffff88887ffabaa8 R09: 0000000000000003
R10: ffff88887fecbac0 R11: ffff88887ff7bac0 R12: ffff8882a21c3968
R13: ffff88811c018940 R14: 0000000000000000 R15: ffff8881274401a0
FS:  00007fe141c81800(0000) GS:ffff88885f980000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f787c28b948 CR3: 000000014bcf3005 CR4: 0000000000370ea0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ? __warn+0x79/0x120
 ? call_netdevice_notifiers_info+0x7c/0x80
 ? report_bug+0x17c/0x190
 ? handle_bug+0x3c/0x60
 ? exc_invalid_op+0x14/0x70
 ? asm_exc_invalid_op+0x16/0x20
 ? call_netdevice_notifiers_info+0x7c/0x80
 ? call_netdevice_notifiers_info+0x7c/0x80
 call_netdevice_notifiers+0x2e/0x50
 mlx5e_set_xdp_feature+0x21/0x50 [mlx5_core]
 mlx5e_nic_init+0xf1/0x1a0 [mlx5_core]
 mlx5e_netdev_init_profile+0x76/0x110 [mlx5_core]
 mlx5e_netdev_attach_profile+0x1f/0x90 [mlx5_core]
 mlx5e_netdev_change_profile+0x92/0x160 [mlx5_core]
 mlx5e_netdev_attach_nic_profile+0x1b/0x30 [mlx5_core]
 mlx5e_vport_rep_unload+0xaa/0xc0 [mlx5_core]
 __esw_offloads_unload_rep+0x52/0x60 [mlx5_core]
 mlx5_esw_offloads_rep_unload+0x52/0x70 [mlx5_core]
 esw_offloads_unload_rep+0x34/0x70 [mlx5_core]
 esw_offloads_disable+0x2b/0x90 [mlx5_core]
 mlx5_eswitch_disable_locked+0x1b9/0x210 [mlx5_core]
 mlx5_devlink_eswitch_mode_set+0xf5/0x630 [mlx5_core]
 ? devlink_get_from_attrs_lock+0x9e/0x110
 devlink_nl_cmd_eswitch_set_doit+0x60/0xe0
 genl_family_rcv_msg_doit.isra.0+0xc2/0x110
 genl_rcv_msg+0x17d/0x2b0
 ? devlink_get_from_attrs_lock+0x110/0x110
 ? devlink_nl_cmd_eswitch_get_doit+0x290/0x290
 ? devlink_pernet_pre_exit+0xf0/0xf0
 ? genl_family_rcv_msg_doit.isra.0+0x110/0x110
 netlink_rcv_skb+0x54/0x100
 genl_rcv+0x24/0x40
 netlink_unicast+0x1f6/0x2c0
 netlink_sendmsg+0x232/0x4a0
 sock_sendmsg+0x38/0x60
 ? _copy_from_user+0x2a/0x60
 __sys_sendto+0x110/0x160
 ? __count_memcg_events+0x48/0x90
 ? handle_mm_fault+0x161/0x260
 ? do_user_addr_fault+0x278/0x6e0
 __x64_sys_sendto+0x20/0x30
 do_syscall_64+0x3d/0x90
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7fe141b1340a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 f3 0f 1e fa 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 15 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 7e c3 0f 1f 44 00 00 41 54 48 83 ec 30 44 89
RSP: 002b:00007fff61d03de8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000afab00 RCX: 00007fe141b1340a
RDX: 0000000000000038 RSI: 0000000000afab00 RDI: 0000000000000003
RBP: 0000000000afa910 R08: 00007fe141d80200 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
 </TASK>

Fixes: 4d5ab0ad964d ("net/mlx5e: take into account device reconfiguration for xdp_features flag")
Signed-off-by: Gal Pressman <[email-masked]>
Reviewed-by: Tariq Toukan <[email-masked]>
Signed-off-by: Saeed Mahameed <[email-masked]>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 1c820119e438..c27df14df145 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -5266,6 +5266,7 @@ void mlx5e_destroy_q_counters(struct mlx5e_priv *priv)
 static int mlx5e_nic_init(struct mlx5_core_dev *mdev,
 			  struct net_device *netdev)
 {
+	const bool take_rtnl = netdev->reg_state == NETREG_REGISTERED;
 	struct mlx5e_priv *priv = netdev_priv(netdev);
 	struct mlx5e_flow_steering *fs;
 	int err;
@@ -5294,9 +5295,19 @@ static int mlx5e_nic_init(struct mlx5_core_dev *mdev,
 		mlx5_core_err(mdev, "TLS initialization failed, %d\n", err);
 
 	mlx5e_health_create_reporters(priv);
+
+	/* If netdev is already registered (e.g. move from uplink to nic profile),
+	 * RTNL lock must be held before triggering netdev notifiers.
+	 */
+	if (take_rtnl)
+		rtnl_lock();
+
 	/* update XDP supported features */
 	mlx5e_set_xdp_feature(netdev);
 
+	if (take_rtnl)
+		rtnl_unlock();
+
 	return 0;
 }
 
-- 
2.41.0