On 16/03/2023 2:29, Jakub Kicinski wrote:
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 <kuba@xxxxxxxxxx>
---
CC: ast@xxxxxxxxxx
CC: daniel@xxxxxxxxxxxxx
CC: hawk@xxxxxxxxxx
CC: john.fastabend@xxxxxxxxx
CC: lorenzo@xxxxxxxxxx
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CC: bpf@xxxxxxxxxxxxxxx
---
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;
I maybe need to dig deeper, but, it looks strange to still
call_netdevice_notifiers in cases > NETREG_REGISTERED.
Isn't it problematic to call it with NETREG_UNREGISTERED ?
For comparison, netif_set_real_num_tx_queues has this ASSERT_RTNL() only
under dev->reg_state == NETREG_REGISTERED || dev->reg_state ==
NETREG_UNREGISTERING.
call_netdevice_notifiers(NETDEV_XDP_FEAT_CHANGE, dev);
}
EXPORT_SYMBOL_GPL(xdp_set_features_flag);
