* [PATCH net-next v2] macvlan: silence RCU list debugging warning
@ 2020-04-22 2:11 Wei Yongjun
2020-04-23 2:34 ` David Miller
0 siblings, 1 reply; 2+ messages in thread
From: Wei Yongjun @ 2020-04-22 2:11 UTC (permalink / raw)
To: Eric Dumazet, Gustavo A. R. Silva, Taehee Yoo, Richard Cochran
Cc: Wei Yongjun, netdev
macvlan_hash_lookup() uses list_for_each_entry_rcu() for traversing
should either under RCU in fast path or the protection of rtnl_mutex.
In the case of holding RTNL, we should add the corresponding lockdep
expression to silence the following false-positive warning:
=============================
WARNING: suspicious RCU usage
5.7.0-rc1-next-20200416-00003-ga3b8d28bc #1 Not tainted
-----------------------------
drivers/net/macvlan.c:126 RCU-list traversed in non-reader section!!
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
---
v1 - > v2: update the changelogs
---
drivers/net/macvlan.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index e7289d67268f..654c1fa11826 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -123,7 +123,8 @@ static struct macvlan_dev *macvlan_hash_lookup(const struct macvlan_port *port,
struct macvlan_dev *vlan;
u32 idx = macvlan_eth_hash(addr);
- hlist_for_each_entry_rcu(vlan, &port->vlan_hash[idx], hlist) {
+ hlist_for_each_entry_rcu(vlan, &port->vlan_hash[idx], hlist,
+ lockdep_rtnl_is_held()) {
if (ether_addr_equal_64bits(vlan->dev->dev_addr, addr))
return vlan;
}
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net-next v2] macvlan: silence RCU list debugging warning
2020-04-22 2:11 [PATCH net-next v2] macvlan: silence RCU list debugging warning Wei Yongjun
@ 2020-04-23 2:34 ` David Miller
0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2020-04-23 2:34 UTC (permalink / raw)
To: weiyongjun1; +Cc: edumazet, gustavo, ap420073, richardcochran, netdev
From: Wei Yongjun <weiyongjun1@huawei.com>
Date: Wed, 22 Apr 2020 10:11:35 +0800
> macvlan_hash_lookup() uses list_for_each_entry_rcu() for traversing
> should either under RCU in fast path or the protection of rtnl_mutex.
>
> In the case of holding RTNL, we should add the corresponding lockdep
> expression to silence the following false-positive warning:
>
> =============================
> WARNING: suspicious RCU usage
> 5.7.0-rc1-next-20200416-00003-ga3b8d28bc #1 Not tainted
> -----------------------------
> drivers/net/macvlan.c:126 RCU-list traversed in non-reader section!!
>
> Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Applied, thanks Wei.
^ permalink raw reply [flat|nested] 2+ messages in thread
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