[PATCH 4.9 58/61] net: rtnl_configure_link: fix dev flags changes arg to __dev_notify_flags

[Greg Kroah-Hartman]

From: Roopa Prabhu <ro...@cumulusnetworks.com>

commit 56a49d7048703f5ffdb84d3a0ee034108fba6850 upstream.

This fix addresses https://bugzilla.kernel.org/show_bug.cgi?id=201071

Commit 5025f7f7d506 wrongly relied on __dev_change_flags to notify users of
dev flag changes in the case when dev->rtnl_link_state = RTNL_LINK_INITIALIZED.
Fix it by indicating flag changes explicitly to __dev_notify_flags.

Fixes: 5025f7f7d506 ("rtnetlink: add rtnl_link_state check in 
rtnl_configure_link")
Reported-By: Liam mcbirnie <liam.mcbir...@boeing.com>
Signed-off-by: Roopa Prabhu <ro...@cumulusnetworks.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Cc: Guenter Roeck <li...@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 net/core/rtnetlink.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2361,7 +2361,7 @@ int rtnl_configure_link(struct net_devic
        }
 
        if (dev->rtnl_link_state == RTNL_LINK_INITIALIZED) {
-               __dev_notify_flags(dev, old_flags, 0U);
+               __dev_notify_flags(dev, old_flags, (old_flags ^ dev->flags));
        } else {
                dev->rtnl_link_state = RTNL_LINK_INITIALIZED;
                __dev_notify_flags(dev, old_flags, ~0U);