* [PATCH net] netlink: ensure to loop over all netns in genlmsg_multicast_allns()
@ 2018-02-06 13:48 Nicolas Dichtel
2018-02-08 19:06 ` David Miller
0 siblings, 1 reply; 2+ messages in thread
From: Nicolas Dichtel @ 2018-02-06 13:48 UTC (permalink / raw)
To: davem; +Cc: netdev, Nicolas Dichtel, Johannes Berg
Nowadays, nlmsg_multicast() returns only 0 or -ESRCH but this was not the
case when commit 134e63756d5f was pushed.
However, there was no reason to stop the loop if a netns does not have
listeners.
Returns -ESRCH only if there was no listeners in all netns.
To avoid having the same problem in the future, I didn't take the
assumption that nlmsg_multicast() returns only 0 or -ESRCH.
Fixes: 134e63756d5f ("genetlink: make netns aware")
CC: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
---
net/netlink/genetlink.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index d444daf1ac04..6f02499ef007 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -1081,6 +1081,7 @@ static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
{
struct sk_buff *tmp;
struct net *net, *prev = NULL;
+ bool delivered = false;
int err;
for_each_net_rcu(net) {
@@ -1092,14 +1093,21 @@ static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
}
err = nlmsg_multicast(prev->genl_sock, tmp,
portid, group, flags);
- if (err)
+ if (!err)
+ delivered = true;
+ else if (err != -ESRCH)
goto error;
}
prev = net;
}
- return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
+ err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
+ if (!err)
+ delivered = true;
+ else if (err != -ESRCH)
+ goto error;
+ return delivered ? 0 : -ESRCH;
error:
kfree_skb(skb);
return err;
--
2.15.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net] netlink: ensure to loop over all netns in genlmsg_multicast_allns()
2018-02-06 13:48 [PATCH net] netlink: ensure to loop over all netns in genlmsg_multicast_allns() Nicolas Dichtel
@ 2018-02-08 19:06 ` David Miller
0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2018-02-08 19:06 UTC (permalink / raw)
To: nicolas.dichtel; +Cc: netdev, johannes.berg
From: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Date: Tue, 6 Feb 2018 14:48:32 +0100
> Nowadays, nlmsg_multicast() returns only 0 or -ESRCH but this was not the
> case when commit 134e63756d5f was pushed.
> However, there was no reason to stop the loop if a netns does not have
> listeners.
> Returns -ESRCH only if there was no listeners in all netns.
>
> To avoid having the same problem in the future, I didn't take the
> assumption that nlmsg_multicast() returns only 0 or -ESRCH.
>
> Fixes: 134e63756d5f ("genetlink: make netns aware")
> CC: Johannes Berg <johannes.berg@intel.com>
> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Ok, that indeed preserves the original behavior. Given this has
been this way since 2.6.32 I wonder if fixing this might break
something.
Regardless, applied and queued up for -stable, thanks.
^ permalink raw reply [flat|nested] 2+ messages in thread
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