[Intel-wired-lan] [bug report] ixgbe: add VF IPsec management

[Dan Carpenter <dan.carpenter@linaro.org>]

Hello Shannon Nelson,

The patch eda0333ac293: "ixgbe: add VF IPsec management" from Aug 13,
2018 (linux-next), leads to the following Smatch static checker
warning:

	drivers/net/ethernet/intel/ixgbe/ixgbe_ipsec.c:917 ixgbe_ipsec_vf_add_sa()
	warn: sleeping in IRQ context

drivers/net/ethernet/intel/ixgbe/ixgbe_ipsec.c
    890 int ixgbe_ipsec_vf_add_sa(struct ixgbe_adapter *adapter, u32 *msgbuf, u32 vf)
    891 {
    892         struct ixgbe_ipsec *ipsec = adapter->ipsec;
    893         struct xfrm_algo_desc *algo;
    894         struct sa_mbx_msg *sam;
    895         struct xfrm_state *xs;
    896         size_t aead_len;
    897         u16 sa_idx;
    898         u32 pfsa;
    899         int err;
    900 
    901         sam = (struct sa_mbx_msg *)(&msgbuf[1]);
    902         if (!adapter->vfinfo[vf].trusted ||
    903             !(adapter->flags2 & IXGBE_FLAG2_VF_IPSEC_ENABLED)) {
    904                 e_warn(drv, "VF %d attempted to add an IPsec SA\n", vf);
    905                 err = -EACCES;
    906                 goto err_out;
    907         }
    908 
    909         /* Tx IPsec offload doesn't seem to work on this
    910          * device, so block these requests for now.
    911          */
    912         if (sam->dir != XFRM_DEV_OFFLOAD_IN) {
    913                 err = -EOPNOTSUPP;
    914                 goto err_out;
    915         }
    916 
--> 917         xs = kzalloc(sizeof(*xs), GFP_KERNEL);
                                          ^^^^^^^^^^
Sleeping allocation.

The call tree that Smatch is worried about is:

ixgbe_msix_other() <- IRQ handler
-> ixgbe_msg_task()
   -> ixgbe_rcv_msg_from_vf()
      -> ixgbe_ipsec_vf_add_sa()

This is a fairly new warning and those have a higher risk of false
positives.  Plus the longer the call tree the higher the chance of
false positives.  However, I did review it and the warning looks
reasonable.

regards,
dan carpenter