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 "ethtool -g/-G" is called on the netdev, the vport associated with the netdev is NULL, and so a kernel panic would happen: [ 513.185327] BUG: kernel NULL pointer dereference, address: 0000000000000038 ... [ 513.232756] RIP: 0010:idpf_get_ringparam+0x45/0x80 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 calling "ethtool -g/-G" on the netdev at the same time. With this patch applied, we see the following error but no kernel panics anymore: [ 476.323630] idpf 0000:05:00.0 eth1: failed to get ring params due to no vport in netdev Signed-off-by: Li Li --- drivers/net/ethernet/intel/idpf/idpf_ethtool.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/net/ethernet/intel/idpf/idpf_ethtool.c b/drivers/net/ethernet/intel/idpf/idpf_ethtool.c index d5711be0b8e69..6a4b630b786c2 100644 --- a/drivers/net/ethernet/intel/idpf/idpf_ethtool.c +++ b/drivers/net/ethernet/intel/idpf/idpf_ethtool.c @@ -639,6 +638,10 @@ static void idpf_get_ringparam(struct net_device *netdev, idpf_vport_ctrl_lock(netdev); vport = idpf_netdev_to_vport(netdev); + if (!vport) { + netdev_err(netdev, "failed to get ring params due to no vport in netdev\n"); + goto unlock; + } ring->rx_max_pending = IDPF_MAX_RXQ_DESC; ring->tx_max_pending = IDPF_MAX_TXQ_DESC; @@ -647,6 +651,7 @@ static void idpf_get_ringparam(struct net_device *netdev, kring->tcp_data_split = idpf_vport_get_hsplit(vport); +unlock: idpf_vport_ctrl_unlock(netdev); } @@ -673,6 +674,11 @@ static int idpf_set_ringparam(struct net_device *netdev, idpf_vport_ctrl_lock(netdev); vport = idpf_netdev_to_vport(netdev); + if (!vport) { + netdev_err(netdev, "ring params not changed due to no vport in netdev\n"); + err = -EFAULT; + goto unlock_mutex; + } idx = vport->idx; -- 2.52.0.351.gbe84eed79e-goog