On Apr 8, 2013, at 8:45 AM, Michael Riesch <[email protected]> wrote:
> > Signed-off-by: Michael Riesch <[email protected]> > Cc: "David S. Miller" <[email protected]> > Cc: Greg Kroah-Hartman <[email protected]> > Cc: Jiri Benc <[email protected]> > Cc: "Theodore Ts'o" <[email protected]> > Cc: [email protected] > --- > Habidere, > > I encountered a netlink kernel warning when running avahi 0.6.31 on my system > with kernel v3.4.35 (it appears several times): > > netlink: 12 bytes leftover after parsing attributes. > > Searching the web showed that commit > "115c9b81928360d769a76c632bae62d15206a94a > rtnetlink: Fix problem with buffer allocation" introduced this behaviour[1]. > > Now I - knowing nothing about netlink whatsoever - assume that the nlmsg_parse > function is called with the wrong header length. In user space the request > message consists out of the message header (struct nlmsghdr, 16 bytes) and an > ifinfomsg (struct ifinfomsg, 16 bytes). After that, request attributes could > follow. nlmsg_parse checks for this attributes after a given header length. In > rtnl_get_link() this header length is sizeof(struct ifinfomsg), but in > rtnl_calcit() as well as in rntl_dump_ifinfo() the header length is > sizeof(struct rtgenmsg), which is 1 byte. > > With this patch I got rid of these warnings. However, I do not know whether > this is the correct solution, so I am looking forward to your comments. > Regards, Michael > > [1] http://lists.infradead.org/pipermail/libnl/2012-April/000515.html > > net/core/rtnetlink.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c > index 900fc61..ebf6ace 100644 > --- a/net/core/rtnetlink.c > +++ b/net/core/rtnetlink.c > @@ -1065,7 +1065,7 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct > netlink_callback *cb) > rcu_read_lock(); > cb->seq = net->dev_base_seq; > > - if (nlmsg_parse(cb->nlh, sizeof(struct rtgenmsg), tb, IFLA_MAX, > + if (nlmsg_parse(cb->nlh, sizeof(struct ifinfomsg), tb, IFLA_MAX, > ifla_policy) >= 0) { > > if (tb[IFLA_EXT_MASK]) > @@ -1909,7 +1909,7 @@ static u16 rtnl_calcit(struct sk_buff *skb, struct > nlmsghdr *nlh) > u32 ext_filter_mask = 0; > u16 min_ifinfo_dump_size = 0; > > - if (nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, IFLA_MAX, > + if (nlmsg_parse(nlh, sizeof(struct ifinfomsg), tb, IFLA_MAX, > ifla_policy) >= 0) { > if (tb[IFLA_EXT_MASK]) > ext_filter_mask = nla_get_u32(tb[IFLA_EXT_MASK]); > -- > 1.7.9.5 I found that fcoemon has also been triggering these messages for some time. I found the same problem and arrived at exactly the same solution. I would have already sent it, but it is still in validation. As far as I am concerned: Acked-by: Mark Rustad <[email protected]> -- Mark Rustad, Networking Division, Intel Corporation-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
