* [PATCH v4] bridge: fix bridge netlink RCU usage
@ 2015-03-03 15:02 Johannes Berg
2015-03-03 16:08 ` roopa
2015-03-04 5:20 ` David Miller
0 siblings, 2 replies; 3+ messages in thread
From: Johannes Berg @ 2015-03-03 15:02 UTC (permalink / raw)
To: netdev; +Cc: Roopa Prabhu, Stephen Hemminger, Johannes Berg
From: Johannes Berg <johannes.berg@intel.com>
When the STP timer fires, it can call br_ifinfo_notify(),
which in turn ends up in the new br_get_link_af_size().
This function is annotated to be using RTNL locking, which
clearly isn't the case here, and thus lockdep warns:
===============================
[ INFO: suspicious RCU usage. ]
3.19.0+ #569 Not tainted
-------------------------------
net/bridge/br_private.h:204 suspicious rcu_dereference_protected() usage!
Fix this by doing RCU locking here.
Fixes: b7853d73e39b ("bridge: add vlan info to bridge setlink and dellink notification messages")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
net/bridge/br_netlink.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 3de0eefe2b82..c72083968768 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -81,17 +81,19 @@ static size_t br_get_link_af_size_filtered(const struct net_device *dev,
struct net_port_vlans *pv;
int num_vlan_infos;
+ rcu_read_lock();
if (br_port_exists(dev))
- pv = nbp_get_vlan_info(br_port_get_rtnl(dev));
+ pv = nbp_get_vlan_info(br_port_get_rcu(dev));
else if (dev->priv_flags & IFF_EBRIDGE)
pv = br_get_vlan_info((struct net_bridge *)netdev_priv(dev));
else
- return 0;
-
- if (!pv)
- return 0;
+ pv = NULL;
+ if (pv)
+ num_vlan_infos = br_get_num_vlan_infos(pv, filter_mask);
+ else
+ num_vlan_infos = 0;
+ rcu_read_unlock();
- num_vlan_infos = br_get_num_vlan_infos(pv, filter_mask);
if (!num_vlan_infos)
return 0;
--
2.1.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v4] bridge: fix bridge netlink RCU usage
2015-03-03 15:02 [PATCH v4] bridge: fix bridge netlink RCU usage Johannes Berg
@ 2015-03-03 16:08 ` roopa
2015-03-04 5:20 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: roopa @ 2015-03-03 16:08 UTC (permalink / raw)
To: Johannes Berg; +Cc: netdev, Stephen Hemminger, Johannes Berg
On 3/3/15, 7:02 AM, Johannes Berg wrote:
> From: Johannes Berg <johannes.berg@intel.com>
>
> When the STP timer fires, it can call br_ifinfo_notify(),
> which in turn ends up in the new br_get_link_af_size().
> This function is annotated to be using RTNL locking, which
> clearly isn't the case here, and thus lockdep warns:
>
> ===============================
> [ INFO: suspicious RCU usage. ]
> 3.19.0+ #569 Not tainted
> -------------------------------
> net/bridge/br_private.h:204 suspicious rcu_dereference_protected() usage!
>
> Fix this by doing RCU locking here.
>
> Fixes: b7853d73e39b ("bridge: add vlan info to bridge setlink and dellink notification messages")
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> ---
> net/bridge/br_netlink.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
> index 3de0eefe2b82..c72083968768 100644
> --- a/net/bridge/br_netlink.c
> +++ b/net/bridge/br_netlink.c
> @@ -81,17 +81,19 @@ static size_t br_get_link_af_size_filtered(const struct net_device *dev,
> struct net_port_vlans *pv;
> int num_vlan_infos;
>
> + rcu_read_lock();
> if (br_port_exists(dev))
> - pv = nbp_get_vlan_info(br_port_get_rtnl(dev));
> + pv = nbp_get_vlan_info(br_port_get_rcu(dev));
> else if (dev->priv_flags & IFF_EBRIDGE)
> pv = br_get_vlan_info((struct net_bridge *)netdev_priv(dev));
> else
> - return 0;
> -
> - if (!pv)
> - return 0;
> + pv = NULL;
> + if (pv)
> + num_vlan_infos = br_get_num_vlan_infos(pv, filter_mask);
> + else
> + num_vlan_infos = 0;
> + rcu_read_unlock();
>
> - num_vlan_infos = br_get_num_vlan_infos(pv, filter_mask);
> if (!num_vlan_infos)
> return 0;
>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
The patch may have to be marked with prefix 'net-next' ?. (unless dave
infers it from the thread)
Thanks again!
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v4] bridge: fix bridge netlink RCU usage
2015-03-03 15:02 [PATCH v4] bridge: fix bridge netlink RCU usage Johannes Berg
2015-03-03 16:08 ` roopa
@ 2015-03-04 5:20 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2015-03-04 5:20 UTC (permalink / raw)
To: johannes; +Cc: netdev, roopa, stephen, johannes.berg
From: Johannes Berg <johannes@sipsolutions.net>
Date: Tue, 3 Mar 2015 16:02:16 +0100
> From: Johannes Berg <johannes.berg@intel.com>
>
> When the STP timer fires, it can call br_ifinfo_notify(),
> which in turn ends up in the new br_get_link_af_size().
> This function is annotated to be using RTNL locking, which
> clearly isn't the case here, and thus lockdep warns:
>
> ===============================
> [ INFO: suspicious RCU usage. ]
> 3.19.0+ #569 Not tainted
> -------------------------------
> net/bridge/br_private.h:204 suspicious rcu_dereference_protected() usage!
>
> Fix this by doing RCU locking here.
>
> Fixes: b7853d73e39b ("bridge: add vlan info to bridge setlink and dellink notification messages")
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Applied to net-next, thanks Johannes.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-03-03 15:02 [PATCH v4] bridge: fix bridge netlink RCU usage Johannes Berg
2015-03-03 16:08 ` roopa
2015-03-04 5:20 ` David Miller
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