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bonding: Fix multiple long standing offload races

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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: 2aeeef906d ("bonding: change ipsec_lock from spin lock to mutex")
Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Tested-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
This commit is contained in:
Cosmin Ratiu 2025-04-11 10:49:58 +03:00 committed by Steffen Klassert
parent fd4e41ebf6
commit d2fddbd347
2 changed files with 41 additions and 48 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

82
drivers/net/bonding/bond_main.c
View File

@ -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);
}
/**

7
include/net/xfrm.h
View File

@ -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;