Subject: [net 07/10] net/mlx5e: Fix mlx5e_priv_init() cleanup flow

From: Saeed Mahameed <[email-masked]>
Date: Tue, 26 Mar 2024 07:46:43 -0700

From: Carolina Jubran <[email-masked]>

When mlx5e_priv_init() fails, the cleanup flow calls mlx5e_selq_cleanup which
calls mlx5e_selq_apply() that assures that the `priv->state_lock` is held using
lockdep_is_held().

Acquire the state_lock in mlx5e_selq_cleanup().

Kernel log:
=============================
WARNING: suspicious RCU usage
6.8.0-rc3_net_next_841a9b5 #1 Not tainted
-----------------------------
drivers/net/ethernet/mellanox/mlx5/core/en/selq.c:124 suspicious rcu_dereference_protected() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
2 locks held by systemd-modules/293:
 #0: ffffffffa05067b0 (devices_rwsem){++++}-{3:3}, at: ib_register_client+0x109/0x1b0 [ib_core]
 #1: ffff8881096c65c0 (&device->client_data_rwsem){++++}-{3:3}, at: add_client_context+0x104/0x1c0 [ib_core]

stack backtrace:
CPU: 4 PID: 293 Comm: systemd-modules Not tainted 6.8.0-rc3_net_next_841a9b5 #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x8a/0xa0
 lockdep_rcu_suspicious+0x154/0x1a0
 mlx5e_selq_apply+0x94/0xa0 [mlx5_core]
 mlx5e_selq_cleanup+0x3a/0x60 [mlx5_core]
 mlx5e_priv_init+0x2be/0x2f0 [mlx5_core]
 mlx5_rdma_setup_rn+0x7c/0x1a0 [mlx5_core]
 rdma_init_netdev+0x4e/0x80 [ib_core]
 ? mlx5_rdma_netdev_free+0x70/0x70 [mlx5_core]
 ipoib_intf_init+0x64/0x550 [ib_ipoib]
 ipoib_intf_alloc+0x4e/0xc0 [ib_ipoib]
 ipoib_add_one+0xb0/0x360 [ib_ipoib]
 add_client_context+0x112/0x1c0 [ib_core]
 ib_register_client+0x166/0x1b0 [ib_core]
 ? 0xffffffffa0573000
 ipoib_init_module+0xeb/0x1a0 [ib_ipoib]
 do_one_initcall+0x61/0x250
 do_init_module+0x8a/0x270
 init_module_from_file+0x8b/0xd0
 idempotent_init_module+0x17d/0x230
 __x64_sys_finit_module+0x61/0xb0
 do_syscall_64+0x71/0x140
 entry_SYSCALL_64_after_hwframe+0x46/0x4e
 </TASK>

Fixes: 8bf30be75069 ("net/mlx5e: Introduce select queue parameters")
Signed-off-by: Carolina Jubran <[email-masked]>
Reviewed-by: Tariq Toukan <[email-masked]>
Reviewed-by: Dragos Tatulea <[email-masked]>
Signed-off-by: Saeed Mahameed <[email-masked]>
---
 drivers/net/ethernet/mellanox/mlx5/core/en/selq.c | 2 ++
 drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 2 --
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/selq.c b/drivers/net/ethernet/mellanox/mlx5/core/en/selq.c
index f675b1926340..f66bbc846464 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/selq.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/selq.c
@@ -57,6 +57,7 @@ int mlx5e_selq_init(struct mlx5e_selq *selq, struct mutex *state_lock)
 
 void mlx5e_selq_cleanup(struct mlx5e_selq *selq)
 {
+	mutex_lock(selq->state_lock);
 	WARN_ON_ONCE(selq->is_prepared);
 
 	kvfree(selq->standby);
@@ -67,6 +68,7 @@ void mlx5e_selq_cleanup(struct mlx5e_selq *selq)
 
 	kvfree(selq->standby);
 	selq->standby = NULL;
+	mutex_unlock(selq->state_lock);
 }
 
 void mlx5e_selq_prepare_params(struct mlx5e_selq *selq, struct mlx5e_params *params)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 91848eae4565..b375ef268671 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -5726,9 +5726,7 @@ void mlx5e_priv_cleanup(struct mlx5e_priv *priv)
 	kfree(priv->tx_rates);
 	kfree(priv->txq2sq);
 	destroy_workqueue(priv->wq);
-	mutex_lock(&priv->state_lock);
 	mlx5e_selq_cleanup(&priv->selq);
-	mutex_unlock(&priv->state_lock);
 	free_cpumask_var(priv->scratchpad.cpumask);
 
 	for (i = 0; i < priv->htb_max_qos_sqs; i++)
-- 
2.44.0