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net: openvswitch: ovs_ct_exit to be done under ovs_lock
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syzbot wrote:
| =============================
| WARNING: suspicious RCU usage
| 5.7.0-rc1+ hardkernel#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/[email protected]
Fixes: 11efd5c ("openvswitch: Support conntrack zone limit")
Cc: Pravin B Shelar <[email protected]>
Cc: Yi-Hung Wei <[email protected]>
Reported-by: [email protected]
Signed-off-by: Tonghao Zhang <[email protected]>
Acked-by: Pravin B Shelar <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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xpu22 authored and davem330 committed Apr 20, 2020
1 parent 9bacd25 commit 27de77c
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Showing 2 changed files with 5 additions and 2 deletions.
3 changes: 2 additions & 1 deletion net/openvswitch/conntrack.c
Original file line number Diff line number Diff line change
Expand Up @@ -1895,7 +1895,8 @@ 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);
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4 changes: 3 additions & 1 deletion net/openvswitch/datapath.c
Original file line number Diff line number Diff line change
Expand Up @@ -2466,8 +2466,10 @@ static void __net_exit ovs_exit_net(struct net *dnet)
struct net *net;
LIST_HEAD(head);

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);

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