From: Ding Tianhong <dingtianhong@huawei•com>
To: Veaceslav Falico <vfalico@redhat•com>, <netdev@vger•kernel.org>
Cc: Jay Vosburgh <fubar@us•ibm.com>, Andy Gospodarek <andy@greyhouse•net>
Subject: Re: [PATCH v2 net-next 1/3] bonding: fix bond_3ad_set_carrier() RCU usage
Date: Thu, 9 Jan 2014 19:39:38 +0800 [thread overview]
Message-ID: <52CE8A7A.3090400@huawei.com> (raw)
In-Reply-To: <1389266425-28365-2-git-send-email-vfalico@redhat.com>
On 2014/1/9 19:20, Veaceslav Falico wrote:
> Currently, its usage is just plainly wrong. It first gets a slave under
> RCU, and, after releasing the RCU lock, continues to use it - whilst it can
> be freed.
>
> Fix this by ensuring that bond_3ad_set_carrier() is either under RCU read
> lock or under the RTNL lock (bond_set_carrier() always holds it).
>
> Fixes: be79bd048ab ("bonding: add RCU for bond_3ad_state_machine_handler()")
> CC: dingtianhong@huawei•com
> CC: Jay Vosburgh <fubar@us•ibm.com>
> CC: Andy Gospodarek <andy@greyhouse•net>
> Signed-off-by: Veaceslav Falico <vfalico@redhat•com>
> ---
>
> Notes:
> v1 -> v2:
> Don't use _rcu primitives as we can be called under RTNL too.
>
> drivers/net/bonding/bond_3ad.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
> index 29db1ca..cf5fab8 100644
> --- a/drivers/net/bonding/bond_3ad.c
> +++ b/drivers/net/bonding/bond_3ad.c
> @@ -1597,9 +1597,9 @@ static void ad_agg_selection_logic(struct aggregator *agg)
> }
> }
>
> - rcu_read_unlock();
> -
> bond_3ad_set_carrier(bond);
> +
> + rcu_read_unlock();
> }
>
> /**
> @@ -2322,15 +2322,14 @@ void bond_3ad_handle_link_change(struct slave *slave, char link)
> *
> * Called by bond_set_carrier(). Return zero if carrier state does not
> * change, nonzero if it does.
> + * The caller must hold RCU read lock or RTNL.
> */
> int bond_3ad_set_carrier(struct bonding *bond)
> {
> struct aggregator *active;
> struct slave *first_slave;
>
> - rcu_read_lock();
> - first_slave = bond_first_slave_rcu(bond);
> - rcu_read_unlock();
> + first_slave = bond_first_slave(bond);
> if (!first_slave)
> return 0;
> active = __get_active_agg(&(SLAVE_AD_INFO(first_slave).aggregator));
>
Agree, thanks.
Acked-by: Ding Tianhong <dingtianhong@huawei•com>
next prev parent reply other threads:[~2014-01-09 11:39 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-09 11:20 [PATCH v2 net-next 0/3] bonding: fix bond_3ad RCU usage Veaceslav Falico
2014-01-09 11:20 ` [PATCH v2 net-next 1/3] bonding: fix bond_3ad_set_carrier() " Veaceslav Falico
2014-01-09 11:39 ` Ding Tianhong [this message]
2014-01-09 11:20 ` [PATCH v2 net-next 2/3] bonding: fix __get_first_agg " Veaceslav Falico
2014-01-09 11:58 ` Ding Tianhong
2014-01-09 11:58 ` Veaceslav Falico
2014-01-09 11:20 ` [PATCH v2 net-next 3/3] bonding: fix __get_active_agg() RCU logic Veaceslav Falico
2014-01-09 12:04 ` Ding Tianhong
2014-01-09 12:13 ` Veaceslav Falico
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