This is a note to let you know that I've just added the patch titled

net/mlx5e: Fix possible deadlock of VXLAN lock

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: net-mlx5e-fix-possible-deadlock-of-vxlan-lock.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Sun Dec 31 11:13:15 CET 2017

From: Gal Pressman galp@mellanox.com Date: Thu, 23 Nov 2017 13:52:28 +0200 Subject: net/mlx5e: Fix possible deadlock of VXLAN lock

From: Gal Pressman galp@mellanox.com

[ Upstream commit 6323514116404cc651df1b7fffa1311ddf8ce647 ]

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: b3f63c3d5e2c ("net/mlx5e: Add netdev support for VXLAN tunneling") Signed-off-by: Gal Pressman galp@mellanox.com Signed-off-by: Saeed Mahameed saeedm@mellanox.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/mellanox/mlx5/core/vxlan.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/vxlan.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/vxlan.c @@ -71,9 +71,9 @@ struct mlx5e_vxlan *mlx5e_vxlan_lookup_p 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

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_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_pr 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); }

Patches currently in stable-queue which might be from galp@mellanox.com are

queue-4.9/net-mlx5e-fix-possible-deadlock-of-vxlan-lock.patch queue-4.9/net-mlx5e-prevent-possible-races-in-vxlan-control-flow.patch queue-4.9/net-mlx5e-add-refcount-to-vxlan-structure.patch queue-4.9/net-mlx5e-fix-features-check-of-ipv6-traffic.patch