Commit 63235141 authored by Gal Pressman's avatar Gal Pressman Committed by Saeed Mahameed

net/mlx5e: Fix possible deadlock of VXLAN lock

mlx5e_vxlan_lookup_port is called both from mlx5e_add_vxlan_port (user
context) and mlx5e_features_check (softirq), but the lock acquired does
not disable bottom half and might result in deadlock. Fix it by simply
replacing spin_lock() with spin_lock_bh().
While at it, replace all unnecessary spin_lock_irq() to spin_lock_bh().

lockdep's WARNING: inconsistent lock state
[  654.028136] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
[  654.028229] swapper/5/0 [HC0[0]:SC1[9]:HE1:SE0] takes:
[  654.028321]  (&(&vxlan_db->lock)->rlock){+.?.}, at: [<ffffffffa06e7f0e>] mlx5e_vxlan_lookup_port+0x1e/0x50 [mlx5_core]
[  654.028528] {SOFTIRQ-ON-W} state was registered at:
[  654.028607]   _raw_spin_lock+0x3c/0x70
[  654.028689]   mlx5e_vxlan_lookup_port+0x1e/0x50 [mlx5_core]
[  654.028794]   mlx5e_vxlan_add_port+0x2e/0x120 [mlx5_core]
[  654.028878]   process_one_work+0x1e9/0x640
[  654.028942]   worker_thread+0x4a/0x3f0
[  654.029002]   kthread+0x141/0x180
[  654.029056]   ret_from_fork+0x24/0x30
[  654.029114] irq event stamp: 579088
[  654.029174] hardirqs last  enabled at (579088): [<ffffffff818f475a>] ip6_finish_output2+0x49a/0x8c0
[  654.029309] hardirqs last disabled at (579087): [<ffffffff818f470e>] ip6_finish_output2+0x44e/0x8c0
[  654.029446] softirqs last  enabled at (579030): [<ffffffff810b3b3d>] irq_enter+0x6d/0x80
[  654.029567] softirqs last disabled at (579031): [<ffffffff810b3c05>] irq_exit+0xb5/0xc0
[  654.029684] other info that might help us debug this:
[  654.029781]  Possible unsafe locking scenario:

[  654.029868]        CPU0
[  654.029908]        ----
[  654.029947]   lock(&(&vxlan_db->lock)->rlock);
[  654.030045]   <Interrupt>
[  654.030090]     lock(&(&vxlan_db->lock)->rlock);
[  654.030162]
 *** DEADLOCK ***

Fixes: b3f63c3d ("net/mlx5e: Add netdev support for VXLAN tunneling")
Signed-off-by: default avatarGal Pressman <galp@mellanox.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@mellanox.com>
parent dbff26e4
......@@ -71,9 +71,9 @@ struct mlx5e_vxlan *mlx5e_vxlan_lookup_port(struct mlx5e_priv *priv, u16 port)
struct mlx5e_vxlan_db *vxlan_db = &priv->vxlan;
struct mlx5e_vxlan *vxlan;
spin_lock(&vxlan_db->lock);
spin_lock_bh(&vxlan_db->lock);
vxlan = radix_tree_lookup(&vxlan_db->tree, port);
spin_unlock(&vxlan_db->lock);
spin_unlock_bh(&vxlan_db->lock);
return vxlan;
}
......@@ -100,9 +100,9 @@ static void mlx5e_vxlan_add_port(struct work_struct *work)
vxlan->udp_port = port;
spin_lock_irq(&vxlan_db->lock);
spin_lock_bh(&vxlan_db->lock);
err = radix_tree_insert(&vxlan_db->tree, vxlan->udp_port, vxlan);
spin_unlock_irq(&vxlan_db->lock);
spin_unlock_bh(&vxlan_db->lock);
if (err)
goto err_free;
......@@ -121,9 +121,9 @@ static void __mlx5e_vxlan_core_del_port(struct mlx5e_priv *priv, u16 port)
struct mlx5e_vxlan_db *vxlan_db = &priv->vxlan;
struct mlx5e_vxlan *vxlan;
spin_lock_irq(&vxlan_db->lock);
spin_lock_bh(&vxlan_db->lock);
vxlan = radix_tree_delete(&vxlan_db->tree, port);
spin_unlock_irq(&vxlan_db->lock);
spin_unlock_bh(&vxlan_db->lock);
if (!vxlan)
return;
......@@ -171,12 +171,12 @@ void mlx5e_vxlan_cleanup(struct mlx5e_priv *priv)
struct mlx5e_vxlan *vxlan;
unsigned int port = 0;
spin_lock_irq(&vxlan_db->lock);
spin_lock_bh(&vxlan_db->lock);
while (radix_tree_gang_lookup(&vxlan_db->tree, (void **)&vxlan, port, 1)) {
port = vxlan->udp_port;
spin_unlock_irq(&vxlan_db->lock);
spin_unlock_bh(&vxlan_db->lock);
__mlx5e_vxlan_core_del_port(priv, (u16)port);
spin_lock_irq(&vxlan_db->lock);
spin_lock_bh(&vxlan_db->lock);
}
spin_unlock_irq(&vxlan_db->lock);
spin_unlock_bh(&vxlan_db->lock);
}
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