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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Liam mcbirnie <liam.mcbirnie@boeing.com>,
        Roopa Prabhu <roopa@cumulusnetworks.com>,
        "David S. Miller" <davem@davemloft.net>,
        Guenter Roeck <linux@roeck-us.net>
Subject: [PATCH 4.14 067/199] net: rtnl_configure_link: fix dev flags changes arg to __dev_notify_flags
Date:   Wed, 22 Apr 2020 11:56:33 +0200
Message-Id: <20200422095104.917614826@linuxfoundation.org>
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From: Roopa Prabhu <roopa@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.mcbirnie@boeing.com>
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2424,7 +2424,7 @@ 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);