When an idpf HW reset is triggered, it clears the vport but does not clear the netdev held by vport: // In idpf_vport_dealloc() called by idpf_init_hard_reset(), // idpf_init_hard_reset() sets IDPF_HR_RESET_IN_PROG, so // idpf_decfg_netdev() doesn't get called. if (!test_bit(IDPF_HR_RESET_IN_PROG, adapter->flags)) idpf_decfg_netdev(vport); // idpf_decfg_netdev() would clear netdev but it isn't called: unregister_netdev(vport->netdev); free_netdev(vport->netdev); vport->netdev = NULL; // Later in idpf_init_hard_reset(), the vport is cleared: kfree(adapter->vports); adapter->vports = NULL; During an idpf HW reset, when userspace gets RX flow classification rules of the netdev, the vport associated with the netdev is NULL, and so a kernel panic would happen: [ 1466.308592] BUG: kernel NULL pointer dereference, address: 0000000000000032 ... [ 1466.356222] RIP: 0010:idpf_get_rxnfc+0x3b/0x70 This can be reproduced reliably by injecting a TX timeout to cause an idpf HW reset, and injecting a virtchnl error to cause the HW reset to fail and retry, while running "ethtool -n" in userspace. With this patch applied, we see the following error but no kernel panics anymore: [ 312.476576] idpf 0000:05:00.0 eth1: failed to get rules due to no vport in netdev Cannot get RX rings: Bad address rxclass: Cannot get RX class rule count: Bad address RX classification rule retrieval failed Signed-off-by: Li Li --- drivers/net/ethernet/intel/idpf/idpf_ethtool.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/net/ethernet/intel/idpf/idpf_ethtool.c b/drivers/net/ethernet/intel/idpf/idpf_ethtool.c index 6a4b630b786c2..c71af85408a29 100644 --- a/drivers/net/ethernet/intel/idpf/idpf_ethtool.c +++ b/drivers/net/ethernet/intel/idpf/idpf_ethtool.c @@ -45,6 +44,11 @@ static int idpf_get_rxnfc(struct net_device *netdev, struct ethtool_rxnfc *cmd, idpf_vport_ctrl_lock(netdev); vport = idpf_netdev_to_vport(netdev); + if (!vport) { + netdev_err(netdev, "failed to get rules due to no vport in netdev\n"); + err = -EFAULT; + goto unlock; + } vport_config = np->adapter->vport_config[np->vport_idx]; user_config = &vport_config->user_config; @@ -85,6 +90,7 @@ static int idpf_get_rxnfc(struct net_device *netdev, struct ethtool_rxnfc *cmd, break; } +unlock: idpf_vport_ctrl_unlock(netdev); return err; -- 2.52.0.351.gbe84eed79e-goog