2019-07-18 16:09:38

by Haishuang Yan

Subject: [PATCH] openvswitch: Fix a possible memory leak on dst_cache

dst_cache should be destroyed when fail to add flow actions.

Fixes: d71785ffc7e7 ("net: add dst_cache to ovs vxlan lwtunnel")
Signed-off-by: Haishuang Yan <[email protected]>
---
net/openvswitch/flow_netlink.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
index d7559c6..1fd1cdd 100644
--- a/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -2608,6 +2608,7 @@ static int validate_and_copy_set_tun(const struct nlattr *attr,
sizeof(*ovs_tun), log);
if (IS_ERR(a)) {
dst_release((struct dst_entry *)tun_dst);
+ dst_cache_destroy(&tun_dst->u.tun_info.dst_cache);
return PTR_ERR(a);
}

--
1.8.3.1

2019-07-18 19:09:27

by David Miller

Subject: Re: [PATCH] openvswitch: Fix a possible memory leak on dst_cache

From: Haishuang Yan <[email protected]>
Date: Fri, 19 Jul 2019 00:07:08 +0800

> dst_cache should be destroyed when fail to add flow actions.
>
> Fixes: d71785ffc7e7 ("net: add dst_cache to ovs vxlan lwtunnel")
> Signed-off-by: Haishuang Yan <[email protected]>

OVS folks, please review.

2019-07-18 22:13:21

by Gregory Rose

Subject: Re: [PATCH] openvswitch: Fix a possible memory leak on dst_cache

On 7/18/2019 9:07 AM, Haishuang Yan wrote:
> dst_cache should be destroyed when fail to add flow actions.
>
> Fixes: d71785ffc7e7 ("net: add dst_cache to ovs vxlan lwtunnel")
> Signed-off-by: Haishuang Yan <[email protected]>
> ---
> net/openvswitch/flow_netlink.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
> index d7559c6..1fd1cdd 100644
> --- a/net/openvswitch/flow_netlink.c
> +++ b/net/openvswitch/flow_netlink.c
> @@ -2608,6 +2608,7 @@ static int validate_and_copy_set_tun(const struct nlattr *attr,
> sizeof(*ovs_tun), log);
> if (IS_ERR(a)) {
> dst_release((struct dst_entry *)tun_dst);
> + dst_cache_destroy(&tun_dst->u.tun_info.dst_cache);
> return PTR_ERR(a);
> }
>

Nack.

dst_release will decrement the ref count and will
call_rcu(&dst->rcu_head, dst_destroy_rcu) if the ref count is zero.  No
other net drivers call dst_destroy SFAICT.

Haishuang,

are you trying to fix some specific problem here?

Thanks,

- Greg

2019-07-19 01:45:15

by Haishuang Yan

Subject: Re: [PATCH] openvswitch: Fix a possible memory leak on dst_cache

> On 2019??7??19??, at ????6:12, Gregory Rose <[email protected]> wrote:
>
> On 7/18/2019 9:07 AM, Haishuang Yan wrote:
>> dst_cache should be destroyed when fail to add flow actions.
>>
>> Fixes: d71785ffc7e7 ("net: add dst_cache to ovs vxlan lwtunnel")
>> Signed-off-by: Haishuang Yan <[email protected]>
>> ---
>> net/openvswitch/flow_netlink.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
>> index d7559c6..1fd1cdd 100644
>> --- a/net/openvswitch/flow_netlink.c
>> +++ b/net/openvswitch/flow_netlink.c
>> @@ -2608,6 +2608,7 @@ static int validate_and_copy_set_tun(const struct nlattr *attr,
>> sizeof(*ovs_tun), log);
>> if (IS_ERR(a)) {
>> dst_release((struct dst_entry *)tun_dst);
>> + dst_cache_destroy(&tun_dst->u.tun_info.dst_cache);
>> return PTR_ERR(a);
>> }
>>
>
> Nack.
>
> dst_release will decrement the ref count and will call_rcu(&dst->rcu_head, dst_destroy_rcu) if the ref count is zero. No other net drivers call dst_destroy SFAICT.
>
> Haishuang,
>
> are you trying to fix some specific problem here?
>
> Thanks,
>
> - Greg
>
>

Greg,

You??re right, dst_cache would be freed in metadata_dst_free:

125
126 if (dst->flags & DST_METADATA)
127 metadata_dst_free((struct metadata_dst *)dst);
128 else
129 kmem_cache_free(dst->ops->kmem_cachep, dst);
130

I thought I encountered a memory leak, but it seems not an issue, thanks for you explanation.