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 v3 net-next 3/3] bonding: fix __get_active_agg() RCU logic
Date: Fri, 10 Jan 2014 18:48:22 +0800 [thread overview]
Message-ID: <52CFCFF6.6040303@huawei.com> (raw)
In-Reply-To: <1389345523-5497-4-git-send-email-vfalico@redhat.com>
On 2014/1/10 17:18, Veaceslav Falico wrote:
> Currently, the implementation is meaningless - once again, we take the
> slave structure and use it after we've exited RCU critical section.
>
> Fix this by removing the rcu_read_lock() from __get_active_agg(), and
> ensuring that all its callers are holding RCU.
>
> Fixes: be79bd048 ("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:
> v2 -> v3:
> Use the RCU primitives.
>
> v1 -> v2:
> Don't use RCU primitives as we can hold RTNL.
>
> drivers/net/bonding/bond_3ad.c | 10 ++++------
> 1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
> index 27dac0e..112afa8 100644
> --- a/drivers/net/bonding/bond_3ad.c
> +++ b/drivers/net/bonding/bond_3ad.c
> @@ -674,6 +674,8 @@ static u32 __get_agg_bandwidth(struct aggregator *aggregator)
> /**
> * __get_active_agg - get the current active aggregator
> * @aggregator: the aggregator we're looking at
> + *
> + * Caller must hold RCU lock.
> */
> static struct aggregator *__get_active_agg(struct aggregator *aggregator)
> {
> @@ -681,13 +683,9 @@ static struct aggregator *__get_active_agg(struct aggregator *aggregator)
> struct list_head *iter;
> struct slave *slave;
>
> - rcu_read_lock();
> bond_for_each_slave_rcu(bond, slave, iter)
> - if (SLAVE_AD_INFO(slave).aggregator.is_active) {
> - rcu_read_unlock();
> + if (SLAVE_AD_INFO(slave).aggregator.is_active)
> return &(SLAVE_AD_INFO(slave).aggregator);
> - }
> - rcu_read_unlock();
>
> return NULL;
> }
> @@ -1495,11 +1493,11 @@ static void ad_agg_selection_logic(struct aggregator *agg)
> struct slave *slave;
> struct port *port;
>
> + rcu_read_lock();
> origin = agg;
> active = __get_active_agg(agg);
> best = (active && agg_device_up(active)) ? active : NULL;
>
> - rcu_read_lock();
> bond_for_each_slave_rcu(bond, slave, iter) {
> agg = &(SLAVE_AD_INFO(slave).aggregator);
>
>
Great.
Acked-by: Ding Tianhong <dingtianhong@huawei•com>
prev parent reply other threads:[~2014-01-10 10:48 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-10 9:18 [PATCH v3 net-next 0/3] bonding: fix bond_3ad RCU usage Veaceslav Falico
2014-01-10 9:18 ` [PATCH v3 net-next 1/3] bonding: fix bond_3ad_set_carrier() " Veaceslav Falico
2014-01-10 10:34 ` Ding Tianhong
2014-01-10 9:18 ` [PATCH v3 net-next 2/3] bonding: fix __get_first_agg " Veaceslav Falico
2014-01-10 10:43 ` Ding Tianhong
2014-01-10 10:53 ` Veaceslav Falico
2014-01-10 9:18 ` [PATCH v3 net-next 3/3] bonding: fix __get_active_agg() RCU logic Veaceslav Falico
2014-01-10 10:48 ` Ding Tianhong [this message]
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