Subject: [PATCH net] net: xdp: don't call notifiers during driver init

From: Jakub Kicinski <[email-masked]>
Date: Wed, 15 Mar 2023 17:29:03 -0700

Drivers will commonly perform feature setting during init, if they use
the xdp_set_features_flag() helper they'll likely run into an ASSERT_RTNL()
inside call_netdevice_notifiers_info().

Don't call the notifier until the device is actually registered.
Nothing should be tracking the device until its registered.

Fixes: 4d5ab0ad964d ("net/mlx5e: take into account device reconfiguration for xdp_features flag")
Signed-off-by: Jakub Kicinski <[email-masked]>
---
CC: [email-masked]
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---
 net/core/xdp.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/core/xdp.c b/net/core/xdp.c
index 87e654b7d06c..5722a1fc6e9e 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -781,6 +781,9 @@ void xdp_set_features_flag(struct net_device *dev, xdp_features_t val)
 		return;
 
 	dev->xdp_features = val;
+
+	if (dev->reg_state < NETREG_REGISTERED)
+		return;
 	call_netdevice_notifiers(NETDEV_XDP_FEAT_CHANGE, dev);
 }
 EXPORT_SYMBOL_GPL(xdp_set_features_flag);
-- 
2.39.2