[Intel-wired-lan] [bug report] ixgbe: Add locking to prevent panic when setting sriov_numvfs to zero

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Piotr Skajewski,

The patch 1e53834ce541: "ixgbe: Add locking to prevent panic when
setting sriov_numvfs to zero" from Jul 15, 2022, leads to the
following Smatch static checker warning:

	drivers/net/ethernet/intel/ixgbe/ixgbe_ipsec.c:911 ixgbe_ipsec_vf_add_sa()
	warn: sleeping in atomic context


drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
  1358  void ixgbe_msg_task(struct ixgbe_adapter *adapter)
  1359  {
  1360          struct ixgbe_hw *hw = &adapter->hw;
  1361          unsigned long flags;
  1362          u32 vf;
  1363  
  1364          spin_lock_irqsave(&adapter->vfs_lock, flags);
                ^^^^^^^^^^^^^^^^^
New locking

  1365          for (vf = 0; vf < adapter->num_vfs; vf++) {
  1366                  /* process any reset requests */
  1367                  if (!ixgbe_check_for_rst(hw, vf))
  1368                          ixgbe_vf_reset_event(adapter, vf);
  1369  
  1370                  /* process any messages pending */
  1371                  if (!ixgbe_check_for_msg(hw, vf))
  1372                          ixgbe_rcv_msg_from_vf(adapter, vf);
  1373  
  1374                  /* process any acks */
  1375                  if (!ixgbe_check_for_ack(hw, vf))
  1376                          ixgbe_rcv_ack_from_vf(adapter, vf);
  1377          }
  1378          spin_unlock_irqrestore(&adapter->vfs_lock, flags);
  1379  }

ixgbe_msg_task() <- disables preempt
-> ixgbe_rcv_msg_from_vf()
   -> ixgbe_ipsec_vf_add_sa() <- sleeps

drivers/net/ethernet/intel/ixgbe/ixgbe_ipsec.c
    884 int ixgbe_ipsec_vf_add_sa(struct ixgbe_adapter *adapter, u32 *msgbuf, u32 vf)
    885 {
    886         struct ixgbe_ipsec *ipsec = adapter->ipsec;
    887         struct xfrm_algo_desc *algo;
    888         struct sa_mbx_msg *sam;
    889         struct xfrm_state *xs;
    890         size_t aead_len;
    891         u16 sa_idx;
    892         u32 pfsa;
    893         int err;
    894 
    895         sam = (struct sa_mbx_msg *)(&msgbuf[1]);
    896         if (!adapter->vfinfo[vf].trusted ||
    897             !(adapter->flags2 & IXGBE_FLAG2_VF_IPSEC_ENABLED)) {
    898                 e_warn(drv, "VF %d attempted to add an IPsec SA\n", vf);
    899                 err = -EACCES;
    900                 goto err_out;
    901         }
    902 
    903         /* Tx IPsec offload doesn't seem to work on this
    904          * device, so block these requests for now.
    905          */
    906         if (sam->dir != XFRM_DEV_OFFLOAD_IN) {
    907                 err = -EOPNOTSUPP;
    908                 goto err_out;
    909         }
    910 
--> 911         xs = kzalloc(sizeof(*xs), GFP_KERNEL);
                                          ^^^^^^^^^^

    912         if (unlikely(!xs)) {
    913                 err = -ENOMEM;
    914                 goto err_out;
    915         }
    916 

regards,
dan carpenter
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