| Message ID | 20170809153912.19733-1-jkbs@redhat.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Jakub Sitnicki <jkbs@redhat.com> Date: Wed, 9 Aug 2017 17:39:12 +0200 > Calls to rtnl_dump_ifinfo() are protected by RTNL lock. So are the > {list,unlist}_netdevice() calls where we bump the net->dev_base_seq > number. > > For this reason net->dev_base_seq can't change under out feet while > we're looping over links in rtnl_dump_ifinfo(). So move the check for > net->dev_base_seq change (since the last time we were called) out of the > loop. > > This way we avoid giving a wrong impression that there are concurrent > updates to the link list going on while we're iterating over them. > > Signed-off-by: Jakub Sitnicki <jkbs@redhat.com> Applied, thanks.
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 9201e36..6b7888e 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -1644,8 +1644,6 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb) s_h = cb->args[0]; s_idx = cb->args[1]; - cb->seq = net->dev_base_seq; - /* A hack to preserve kernel<->userspace interface. * The correct header is ifinfomsg. It is consistent with rtnl_getlink. * However, before Linux v3.9 the code here assumed rtgenmsg and that's @@ -1691,8 +1689,6 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb) goto out_err; } - - nl_dump_check_consistent(cb, nlmsg_hdr(skb)); cont: idx++; } @@ -1702,6 +1698,8 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb) out_err: cb->args[1] = idx; cb->args[0] = h; + cb->seq = net->dev_base_seq; + nl_dump_check_consistent(cb, nlmsg_hdr(skb)); return err; }
Calls to rtnl_dump_ifinfo() are protected by RTNL lock. So are the {list,unlist}_netdevice() calls where we bump the net->dev_base_seq number. For this reason net->dev_base_seq can't change under out feet while we're looping over links in rtnl_dump_ifinfo(). So move the check for net->dev_base_seq change (since the last time we were called) out of the loop. This way we avoid giving a wrong impression that there are concurrent updates to the link list going on while we're iterating over them. Signed-off-by: Jakub Sitnicki <jkbs@redhat.com> --- net/core/rtnetlink.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)