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Message-ID: <20250411074958.2858496-7-cratiu@nvidia.com>
Date: Fri, 11 Apr 2025 10:49:58 +0300
From: Cosmin Ratiu <cratiu@...dia.com>
To: <netdev@...r.kernel.org>, <cratiu@...dia.com>
CC: Hangbin Liu <liuhangbin@...il.com>, Jay Vosburgh <jv@...sburgh.net>,
Andrew Lunn <andrew+netdev@...n.ch>, "David S . Miller"
<davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski
<kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, Nikolay Aleksandrov
<razor@...ckwall.org>, Simon Horman <horms@...nel.org>, Saeed Mahameed
<saeedm@...dia.com>, Tariq Toukan <tariqt@...dia.com>, Jianbo Liu
<jianbol@...dia.com>, Steffen Klassert <steffen.klassert@...unet.com>,
Herbert Xu <herbert@...dor.apana.org.au>, Ayush Sawal
<ayush.sawal@...lsio.com>, Tony Nguyen <anthony.l.nguyen@...el.com>, "Przemek
Kitszel" <przemyslaw.kitszel@...el.com>, Sunil Goutham
<sgoutham@...vell.com>, Geetha sowjanya <gakula@...vell.com>, Subbaraya
Sundeep <sbhatta@...vell.com>, hariprasad <hkelam@...vell.com>, Bharat
Bhushan <bbhushan2@...vell.com>, Louis Peens <louis.peens@...igine.com>,
"Leon Romanovsky" <leonro@...dia.com>, <linux-kselftest@...r.kernel.org>
Subject: [PATCH net-next v3 6/6] bonding: Fix multiple long standing offload races
Refactor the bonding ipsec offload operations to fix a number of
long-standing control plane races between state migration and user
deletion and a few other issues.
xfrm state deletion can happen concurrently with
bond_change_active_slave() operation. This manifests itself as a
bond_ipsec_del_sa() call with x->lock held, followed by a
bond_ipsec_free_sa() a bit later from a wq. The alternate path of
these calls coming from xfrm_dev_state_flush() can't happen, as that
needs the RTNL lock and bond_change_active_slave() already holds it.
1. bond_ipsec_del_sa_all() might call xdo_dev_state_delete() a second
time on an xfrm state that was concurrently killed. This is bad.
2. bond_ipsec_add_sa_all() can add a state on the new device, but
pending bond_ipsec_free_sa() calls from the old device will then hit
the WARN_ON() and then, worse, call xdo_dev_state_free() on the new
device without a corresponding xdo_dev_state_delete().
3. Resolve a sleeping in atomic context introduced by the mentioned
"Fixes" commit.
bond_ipsec_del_sa_all() and bond_ipsec_add_sa_all() now acquire x->lock
and check for x->km.state to help with problems 1 and 2. And since
xso.real_dev is now a private pointer managed by the bonding driver in
xfrm state, make better use of it to fully fix problems 1 and 2. In
bond_ipsec_del_sa_all(), set xso.real_dev to NULL while holding both the
mutex and x->lock, which makes sure that neither bond_ipsec_del_sa() nor
bond_ipsec_free_sa() could run concurrently.
Fix problem 3 by moving the list cleanup (which requires the mutex) from
bond_ipsec_del_sa() (called from atomic context) to bond_ipsec_free_sa()
Finally, simplify bond_ipsec_del_sa() and bond_ipsec_free_sa() by using
xso->real_dev directly, since it's now protected by locks and can be
trusted to always reflect the offload device.
Fixes: 2aeeef906d5a ("bonding: change ipsec_lock from spin lock to mutex")
Signed-off-by: Cosmin Ratiu <cratiu@...dia.com>
Reviewed-by: Leon Romanovsky <leonro@...dia.com>
---
drivers/net/bonding/bond_main.c | 82 +++++++++++++++------------------
include/net/xfrm.h | 7 ++-
2 files changed, 41 insertions(+), 48 deletions(-)
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 14f7c9712ad4..8ed8c29659a0 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -545,7 +545,20 @@ static void bond_ipsec_add_sa_all(struct bonding *bond)
slave_warn(bond_dev, real_dev, "%s: failed to add SA\n", __func__);
continue;
}
+
+ spin_lock_bh(&ipsec->xs->lock);
+ /* xs might have been killed by the user during the migration
+ * to the new dev, but bond_ipsec_del_sa() should have done
+ * nothing, as xso.real_dev is NULL.
+ * Delete it from the device we just added it to. The pending
+ * bond_ipsec_free_sa() call will do the rest of the cleanup.
+ */
+ if (ipsec->xs->km.state == XFRM_STATE_DEAD &&
+ real_dev->xfrmdev_ops->xdo_dev_state_delete)
+ real_dev->xfrmdev_ops->xdo_dev_state_delete(real_dev,
+ ipsec->xs);
ipsec->xs->xso.real_dev = real_dev;
+ spin_unlock_bh(&ipsec->xs->lock);
}
out:
mutex_unlock(&bond->ipsec_lock);
@@ -560,48 +573,20 @@ static void bond_ipsec_del_sa(struct net_device *bond_dev,
struct xfrm_state *xs)
{
struct net_device *real_dev;
- netdevice_tracker tracker;
- struct bond_ipsec *ipsec;
- struct bonding *bond;
- struct slave *slave;
- if (!bond_dev)
+ if (!bond_dev || !xs->xso.real_dev)
return;
- rcu_read_lock();
- bond = netdev_priv(bond_dev);
- slave = rcu_dereference(bond->curr_active_slave);
- real_dev = slave ? slave->dev : NULL;
- netdev_hold(real_dev, &tracker, GFP_ATOMIC);
- rcu_read_unlock();
-
- if (!slave)
- goto out;
-
- if (!xs->xso.real_dev)
- goto out;
-
- WARN_ON(xs->xso.real_dev != real_dev);
+ real_dev = xs->xso.real_dev;
if (!real_dev->xfrmdev_ops ||
!real_dev->xfrmdev_ops->xdo_dev_state_delete ||
netif_is_bond_master(real_dev)) {
slave_warn(bond_dev, real_dev, "%s: no slave xdo_dev_state_delete\n", __func__);
- goto out;
+ return;
}
real_dev->xfrmdev_ops->xdo_dev_state_delete(real_dev, xs);
-out:
- netdev_put(real_dev, &tracker);
- mutex_lock(&bond->ipsec_lock);
- list_for_each_entry(ipsec, &bond->ipsec_list, list) {
- if (ipsec->xs == xs) {
- list_del(&ipsec->list);
- kfree(ipsec);
- break;
- }
- }
- mutex_unlock(&bond->ipsec_lock);
}
static void bond_ipsec_del_sa_all(struct bonding *bond)
@@ -629,9 +614,15 @@ static void bond_ipsec_del_sa_all(struct bonding *bond)
__func__);
continue;
}
+
+ spin_lock_bh(&ipsec->xs->lock);
ipsec->xs->xso.real_dev = NULL;
- real_dev->xfrmdev_ops->xdo_dev_state_delete(real_dev,
- ipsec->xs);
+ /* Don't double delete states killed by the user. */
+ if (ipsec->xs->km.state != XFRM_STATE_DEAD)
+ real_dev->xfrmdev_ops->xdo_dev_state_delete(real_dev,
+ ipsec->xs);
+ spin_unlock_bh(&ipsec->xs->lock);
+
if (real_dev->xfrmdev_ops->xdo_dev_state_free)
real_dev->xfrmdev_ops->xdo_dev_state_free(real_dev,
ipsec->xs);
@@ -643,34 +634,33 @@ static void bond_ipsec_free_sa(struct net_device *bond_dev,
struct xfrm_state *xs)
{
struct net_device *real_dev;
- netdevice_tracker tracker;
+ struct bond_ipsec *ipsec;
struct bonding *bond;
- struct slave *slave;
if (!bond_dev)
return;
- rcu_read_lock();
bond = netdev_priv(bond_dev);
- slave = rcu_dereference(bond->curr_active_slave);
- real_dev = slave ? slave->dev : NULL;
- netdev_hold(real_dev, &tracker, GFP_ATOMIC);
- rcu_read_unlock();
-
- if (!slave)
- goto out;
+ mutex_lock(&bond->ipsec_lock);
if (!xs->xso.real_dev)
goto out;
- WARN_ON(xs->xso.real_dev != real_dev);
+ real_dev = xs->xso.real_dev;
xs->xso.real_dev = NULL;
- if (real_dev && real_dev->xfrmdev_ops &&
+ if (real_dev->xfrmdev_ops &&
real_dev->xfrmdev_ops->xdo_dev_state_free)
real_dev->xfrmdev_ops->xdo_dev_state_free(real_dev, xs);
out:
- netdev_put(real_dev, &tracker);
+ list_for_each_entry(ipsec, &bond->ipsec_list, list) {
+ if (ipsec->xs == xs) {
+ list_del(&ipsec->list);
+ kfree(ipsec);
+ break;
+ }
+ }
+ mutex_unlock(&bond->ipsec_lock);
}
/**
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 3d2f6c879311..b7e8f3f49627 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -154,8 +154,11 @@ struct xfrm_dev_offload {
*/
struct net_device *dev;
netdevice_tracker dev_tracker;
- /* This is a private pointer used by the bonding driver.
- * Device drivers should not use it.
+ /* This is a private pointer used by the bonding driver (and eventually
+ * should be moved there). Device drivers should not use it.
+ * Protected by xfrm_state.lock AND bond.ipsec_lock in most cases,
+ * except in the .xdo_dev_state_del() flow, where only xfrm_state.lock
+ * is held.
*/
struct net_device *real_dev;
unsigned long offload_handle;
--
2.45.0
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