Re: [Xen-devel] [PATCH] net/bridge: Add missing in6_dev_put in br_validate_ipv6
On 07/04/2015 02:01 AM, Julien Grall wrote: The commit efb6de9b4ba0092b2c55f6a52d16294a8a698edd netfilter: bridge: forward IPv6 fragmented packets introduced a new function br_validate_ipv6 which take a reference on the inet6 device. Although, the reference is not released at the end. This will result to the impossibility to destroy any netdevice using ipv6 and bridge. Spotted while trying to destroy a Xen guest on the upstream Linux: unregister_netdevice: waiting for vif1.0 to become free. Usage count = 1 Signed-off-by: Julien Grall julien.gr...@citrix.com Also hit the same issue, thank you for the fix. Tested-by: Bob Liu bob@oracle.com Cc: Bernhard Thaler bernhard.tha...@wvnet.at Cc: Pablo Neira Ayuso pa...@netfilter.org Cc: f...@strlen.de Cc: ian.campb...@citrix.com Cc: wei.l...@citrix.com --- Note that it's impossible to create new guest after this message. I'm not sure if it's normal. --- net/bridge/br_netfilter_ipv6.c | 5 + 1 file changed, 5 insertions(+) diff --git a/net/bridge/br_netfilter_ipv6.c b/net/bridge/br_netfilter_ipv6.c index 6d12d26..7046e19 100644 --- a/net/bridge/br_netfilter_ipv6.c +++ b/net/bridge/br_netfilter_ipv6.c @@ -140,11 +140,16 @@ int br_validate_ipv6(struct sk_buff *skb) /* No IP options in IPv6 header; however it should be * checked if some next headers need special treatment */ + + in6_dev_put(idev); + return 0; inhdr_error: IP6_INC_STATS_BH(dev_net(dev), idev, IPSTATS_MIB_INHDRERRORS); drop: + in6_dev_put(idev); + return -1; } ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH] net/bridge: Add missing in6_dev_put in br_validate_ipv6
On Mon, 2015-07-06 at 11:35 +0100, Julien Grall wrote:
__in6_dev_get requires to hold rcu_read_lock or RTNL. My knowledge on
this code is very limited. Are we sure that one this lock is hold? At
first glance, I wasn't able to find one.
You could play it safe ;)
diff --git a/net/bridge/br_netfilter_ipv6.c b/net/bridge/br_netfilter_ipv6.c
index 6d12d2675c80..90e8ccc21cc5 100644
--- a/net/bridge/br_netfilter_ipv6.c
+++ b/net/bridge/br_netfilter_ipv6.c
@@ -104,10 +104,12 @@ int br_validate_ipv6(struct sk_buff *skb)
{
const struct ipv6hdr *hdr;
struct net_device *dev = skb-dev;
- struct inet6_dev *idev = in6_dev_get(skb-dev);
+ struct inet6_dev *idev;
u32 pkt_len;
u8 ip6h_len = sizeof(struct ipv6hdr);
+ rcu_read_lock();
+ idev = __in6_dev_get(dev);
if (!pskb_may_pull(skb, ip6h_len))
goto inhdr_error;
@@ -140,11 +142,13 @@ int br_validate_ipv6(struct sk_buff *skb)
/* No IP options in IPv6 header; however it should be
* checked if some next headers need special treatment
*/
+ rcu_read_unlock();
return 0;
inhdr_error:
IP6_INC_STATS_BH(dev_net(dev), idev, IPSTATS_MIB_INHDRERRORS);
drop:
+ rcu_read_unlock();
return -1;
}
___
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Re: [Xen-devel] [PATCH] net/bridge: Add missing in6_dev_put in br_validate_ipv6
Hi, On 03/07/15 21:42, Florian Westphal wrote: Julien Grall julien.gr...@citrix.com wrote: The commit efb6de9b4ba0092b2c55f6a52d16294a8a698edd netfilter: bridge: forward IPv6 fragmented packets introduced a new function br_validate_ipv6 which take a reference on the inet6 device. Although, the reference is not released at the end. This will result to the impossibility to destroy any netdevice using ipv6 and bridge. Spotted while trying to destroy a Xen guest on the upstream Linux: unregister_netdevice: waiting for vif1.0 to become free. Usage count = 1 Ugh :-/ I think it makes more sense to use __in6_dev_get() instead which doesn't take a reference. __in6_dev_get requires to hold rcu_read_lock or RTNL. My knowledge on this code is very limited. Are we sure that one this lock is hold? At first glance, I wasn't able to find one. Regards, -- Julien Grall ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH] net/bridge: Add missing in6_dev_put in br_validate_ipv6
Julien Grall julien.gr...@citrix.com wrote: On 03/07/15 21:42, Florian Westphal wrote: I think it makes more sense to use __in6_dev_get() instead which doesn't take a reference. __in6_dev_get requires to hold rcu_read_lock or RTNL. My knowledge on this code is very limited. Are we sure that one this lock is hold? At first glance, I wasn't able to find one. All netfilter hooks are rcu_read_locked via nf_hook_slow(). BTW, netfilter patches should be sent to netfilter-de...@vger.kernel.org. ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH] net/bridge: Add missing in6_dev_put in br_validate_ipv6
Julien Grall julien.gr...@citrix.com wrote: The commit efb6de9b4ba0092b2c55f6a52d16294a8a698edd netfilter: bridge: forward IPv6 fragmented packets introduced a new function br_validate_ipv6 which take a reference on the inet6 device. Although, the reference is not released at the end. This will result to the impossibility to destroy any netdevice using ipv6 and bridge. Spotted while trying to destroy a Xen guest on the upstream Linux: unregister_netdevice: waiting for vif1.0 to become free. Usage count = 1 Ugh :-/ I think it makes more sense to use __in6_dev_get() instead which doesn't take a reference. ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
[Xen-devel] [PATCH] net/bridge: Add missing in6_dev_put in br_validate_ipv6
The commit efb6de9b4ba0092b2c55f6a52d16294a8a698edd netfilter: bridge: forward IPv6 fragmented packets introduced a new function br_validate_ipv6 which take a reference on the inet6 device. Although, the reference is not released at the end. This will result to the impossibility to destroy any netdevice using ipv6 and bridge. Spotted while trying to destroy a Xen guest on the upstream Linux: unregister_netdevice: waiting for vif1.0 to become free. Usage count = 1 Signed-off-by: Julien Grall julien.gr...@citrix.com Cc: Bernhard Thaler bernhard.tha...@wvnet.at Cc: Pablo Neira Ayuso pa...@netfilter.org Cc: f...@strlen.de Cc: ian.campb...@citrix.com Cc: wei.l...@citrix.com --- Note that it's impossible to create new guest after this message. I'm not sure if it's normal. --- net/bridge/br_netfilter_ipv6.c | 5 + 1 file changed, 5 insertions(+) diff --git a/net/bridge/br_netfilter_ipv6.c b/net/bridge/br_netfilter_ipv6.c index 6d12d26..7046e19 100644 --- a/net/bridge/br_netfilter_ipv6.c +++ b/net/bridge/br_netfilter_ipv6.c @@ -140,11 +140,16 @@ int br_validate_ipv6(struct sk_buff *skb) /* No IP options in IPv6 header; however it should be * checked if some next headers need special treatment */ + + in6_dev_put(idev); + return 0; inhdr_error: IP6_INC_STATS_BH(dev_net(dev), idev, IPSTATS_MIB_INHDRERRORS); drop: + in6_dev_put(idev); + return -1; } -- 2.1.4 ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
