Merge tag 'net-5.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from Jakub Kicinski:
 "Networking fixes for 5.14-rc4, including fixes from bpf, can, WiFi
  (mac80211) and netfilter trees.

  Current release - regressions:

   - mac80211: fix starting aggregation sessions on mesh interfaces

  Current release - new code bugs:

   - sctp: send pmtu probe only if packet loss in Search Complete state

   - bnxt_en: add missing periodic PHC overflow check

   - devlink: fix phys_port_name of virtual port and merge error

   - hns3: change the method of obtaining default ptp cycle

   - can: mcba_usb_start(): add missing urb->transfer_dma initialization

  Previous releases - regressions:

   - set true network header for ECN decapsulation

   - mlx5e: RX, avoid possible data corruption w/ relaxed ordering and
     LRO

   - phy: re-add check for PHY_BRCM_DIS_TXCRXC_NOENRGY on the BCM54811
     PHY

   - sctp: fix return value check in __sctp_rcv_asconf_lookup

  Previous releases - always broken:

   - bpf:
       - more spectre corner case fixes, introduce a BPF nospec
         instruction for mitigating Spectre v4
       - fix OOB read when printing XDP link fdinfo
       - sockmap: fix cleanup related races

   - mac80211: fix enabling 4-address mode on a sta vif after assoc

   - can:
       - raw: raw_setsockopt(): fix raw_rcv panic for sock UAF
       - j1939: j1939_session_deactivate(): clarify lifetime of session
         object, avoid UAF
       - fix number of identical memory leaks in USB drivers

   - tipc:
       - do not blindly write skb_shinfo frags when doing decryption
       - fix sleeping in tipc accept routine"

* tag 'net-5.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (91 commits)
  gve: Update MAINTAINERS list
  can: esd_usb2: fix memory leak
  can: ems_usb: fix memory leak
  can: usb_8dev: fix memory leak
  can: mcba_usb_start(): add missing urb->transfer_dma initialization
  can: hi311x: fix a signedness bug in hi3110_cmd()
  MAINTAINERS: add Yasushi SHOJI as reviewer for the Microchip CAN BUS Analyzer Tool driver
  bpf: Fix leakage due to insufficient speculative store bypass mitigation
  bpf: Introduce BPF nospec instruction for mitigating Spectre v4
  sis900: Fix missing pci_disable_device() in probe and remove
  net: let flow have same hash in two directions
  nfc: nfcsim: fix use after free during module unload
  tulip: windbond-840: Fix missing pci_disable_device() in probe and remove
  sctp: fix return value check in __sctp_rcv_asconf_lookup
  nfc: s3fwrn5: fix undefined parameter values in dev_err()
  net/mlx5: Fix mlx5_vport_tbl_attr chain from u16 to u32
  net/mlx5e: Fix nullptr in mlx5e_hairpin_get_mdev()
  net/mlx5: Unload device upon firmware fatal error
  net/mlx5e: Fix page allocation failure for ptp-RQ over SF
  net/mlx5e: Fix page allocation failure for trap-RQ over SF
  ...

1 files changed, 31 insertions, 2 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index 629a61e8022f..d273758255c3 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -452,12 +452,32 @@ static void mlx5e_detach_mod_hdr(struct mlx5e_priv *priv,
 static
 struct mlx5_core_dev *mlx5e_hairpin_get_mdev(struct net *net, int ifindex)
 {
+	struct mlx5_core_dev *mdev;
 	struct net_device *netdev;
 	struct mlx5e_priv *priv;
 
-	netdev = __dev_get_by_index(net, ifindex);
+	netdev = dev_get_by_index(net, ifindex);
+	if (!netdev)
+		return ERR_PTR(-ENODEV);
+
 	priv = netdev_priv(netdev);
-	return priv->mdev;
+	mdev = priv->mdev;
+	dev_put(netdev);
+
+	/* Mirred tc action holds a refcount on the ifindex net_device (see
+	 * net/sched/act_mirred.c:tcf_mirred_get_dev). So, it's okay to continue using mdev
+	 * after dev_put(netdev), while we're in the context of adding a tc flow.
+	 *
+	 * The mdev pointer corresponds to the peer/out net_device of a hairpin. It is then
+	 * stored in a hairpin object, which exists until all flows, that refer to it, get
+	 * removed.
+	 *
+	 * On the other hand, after a hairpin object has been created, the peer net_device may
+	 * be removed/unbound while there are still some hairpin flows that are using it. This
+	 * case is handled by mlx5e_tc_hairpin_update_dead_peer, which is hooked to
+	 * NETDEV_UNREGISTER event of the peer net_device.
+	 */
+	return mdev;
 }
 
 static int mlx5e_hairpin_create_transport(struct mlx5e_hairpin *hp)
@@ -666,6 +686,10 @@ mlx5e_hairpin_create(struct mlx5e_priv *priv, struct mlx5_hairpin_params *params
 
 	func_mdev = priv->mdev;
 	peer_mdev = mlx5e_hairpin_get_mdev(dev_net(priv->netdev), peer_ifindex);
+	if (IS_ERR(peer_mdev)) {
+		err = PTR_ERR(peer_mdev);
+		goto create_pair_err;
+	}
 
 	pair = mlx5_core_hairpin_create(func_mdev, peer_mdev, params);
 	if (IS_ERR(pair)) {
@@ -804,6 +828,11 @@ static int mlx5e_hairpin_flow_add(struct mlx5e_priv *priv,
 	int err;
 
 	peer_mdev = mlx5e_hairpin_get_mdev(dev_net(priv->netdev), peer_ifindex);
+	if (IS_ERR(peer_mdev)) {
+		NL_SET_ERR_MSG_MOD(extack, "invalid ifindex of mirred device");
+		return PTR_ERR(peer_mdev);
+	}
+
 	if (!MLX5_CAP_GEN(priv->mdev, hairpin) || !MLX5_CAP_GEN(peer_mdev, hairpin)) {
 		NL_SET_ERR_MSG_MOD(extack, "hairpin is not supported");
 		return -EOPNOTSUPP;