Hi Cosmin,
On Mon, Apr 07, 2025 at 04:35:42PM +0300, Cosmin Ratiu wrote:
> 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_free_sa() by not using current_active_slave
> at all, because now that xso.real_dev is protected by locks it 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 <[email protected]>
> Reviewed-by: Leon Romanovsky <[email protected]>
> ---
> drivers/net/bonding/bond_main.c | 58 +++++++++++++++++++--------------
> 1 file changed, 33 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> index 443624504767..ede3287318f8 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -544,7 +544,20 @@ 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);
> @@ -559,7 +572,6 @@ static void bond_ipsec_del_sa(struct net_device *bond_dev,
> {
> struct net_device *real_dev;
> netdevice_tracker tracker;
> - struct bond_ipsec *ipsec;
> struct bonding *bond;
> struct slave *slave;
>
> @@ -591,15 +603,6 @@ static void bond_ipsec_del_sa(struct net_device
> *bond_dev,
> real_dev->xfrmdev_ops->xdo_dev_state_delete(real_dev, xs);
Thanks a lot for the fixes. With your patch applied. I see the
bond_ipsec_del_sa() still has WARN_ON(xs->xso.real_dev != real_dev);
Do you think if we still has this possibility? If yes, should we do
xdo_dev_state_delete() on xs->xso.real_dev or real_dev?
Thanks
Hangbin
