[ovs-dev] [PATCH 2/2] datapath: ovs_ct_exit to be done under ovs_lock

Tonghao Zhang xiangxia.m.yue at gmail.com
Fri Oct 23 01:41:41 UTC 2020


On Thu, Oct 22, 2020 at 12:49 AM Greg Rose <gvrose8192 at gmail.com> wrote:
>
> From: Tonghao Zhang <xiangxia.m.yue at gmail.com>
>
> Upstream commit:
>     commit 27de77cec985233bdf6546437b9761853265c505
>     Author: Tonghao Zhang <xiangxia.m.yue at gmail.com>
>     Date:   Fri Apr 17 02:57:31 2020 +0800
>
>     net: openvswitch: ovs_ct_exit to be done under ovs_lock
>
>     syzbot wrote:
>     | =============================
>     | WARNING: suspicious RCU usage
>     | 5.7.0-rc1+ #45 Not tainted
>     | -----------------------------
>     | net/openvswitch/conntrack.c:1898 RCU-list traversed in non-reader section!!
>     |
>     | other info that might help us debug this:
>     | rcu_scheduler_active = 2, debug_locks = 1
>     | ...
>     |
>     | stack backtrace:
>     | Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
>     | Workqueue: netns cleanup_net
>     | Call Trace:
>     | ...
>     | ovs_ct_exit
>     | ovs_exit_net
>     | ops_exit_list.isra.7
>     | cleanup_net
>     | process_one_work
>     | worker_thread
>
>     To avoid that warning, invoke the ovs_ct_exit under ovs_lock and add
>     lockdep_ovsl_is_held as optional lockdep expression.
>
>     Link: https://lore.kernel.org/lkml/000000000000e642a905a0cbee6e@google.com
>     Fixes: 11efd5cb04a1 ("openvswitch: Support conntrack zone limit")
>     Cc: Pravin B Shelar <pshelar at ovn.org>
>     Cc: Yi-Hung Wei <yihung.wei at gmail.com>
>     Reported-by: syzbot+7ef50afd3a211f879112 at syzkaller.appspotmail.com
>     Signed-off-by: Tonghao Zhang <xiangxia.m.yue at gmail.com>
>     Acked-by: Pravin B Shelar <pshelar at ovn.org>
>     Signed-off-by: David S. Miller <davem at davemloft.net>
>
> Cc: Tonghao Zhang <xiangxia.m.yue at gmail.com>
> Fixes: cb2a5486a3a3 ("datapath: conntrack: Support conntrack zone limit")
> Signed-off-by: Greg Rose <gvrose8192 at gmail.com>
Acked-by: Tonghao Zhang <xiangxia.m.yue at gmail.com>
Thanks Greg

> ---
>  datapath/conntrack.c | 3 ++-
>  datapath/datapath.c  | 4 +++-
>  2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/datapath/conntrack.c b/datapath/conntrack.c
> index c7a318baf..50b4d7bd6 100644
> --- a/datapath/conntrack.c
> +++ b/datapath/conntrack.c
> @@ -1984,7 +1984,8 @@ static void ovs_ct_limit_exit(struct net *net, struct ovs_net *ovs_net)
>                 struct hlist_head *head = &info->limits[i];
>                 struct ovs_ct_limit *ct_limit;
>
> -               hlist_for_each_entry_rcu(ct_limit, head, hlist_node)
> +               hlist_for_each_entry_rcu(ct_limit, head, hlist_node,
> +                                        lockdep_ovsl_is_held())
>                         kfree_rcu(ct_limit, rcu);
>         }
>         kfree(ovs_net->ct_limit_info->limits);
> diff --git a/datapath/datapath.c b/datapath/datapath.c
> index 52a59f135..97ba5fb72 100644
> --- a/datapath/datapath.c
> +++ b/datapath/datapath.c
> @@ -2576,8 +2576,10 @@ static void __net_exit ovs_exit_net(struct net *dnet)
>
>         ovs_netns_frags6_exit(dnet);
>         ovs_netns_frags_exit(dnet);
> -       ovs_ct_exit(dnet);
>         ovs_lock();
> +
> +       ovs_ct_exit(dnet);
> +
>         list_for_each_entry_safe(dp, dp_next, &ovs_net->dps, list_node)
>                 __dp_destroy(dp);
>
> --
> 2.17.1
>


-- 
Best regards, Tonghao


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