i40e: avoid null pointer dereference

In function i40e_debug_aq parameter desc is assumed to be
possibly NULL. Do not dereference it before checking the
value.

Fixes: f905dd62be88 ("i40e/i40evf: add max buf len to aq debug print helper")
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/i40e/i40e_common.c b/drivers/net/ethernet/intel/i40e/i40e_common.c
index e447dc4354647751c84d561a8c441229056e038d..bb63df854ab490e6eba4a77de7710773c6658dd6 100644 (file)
--- a/drivers/net/ethernet/intel/i40e/i40e_common.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_common.c
@@ -297,13 +297,15 @@ void i40e_debug_aq(struct i40e_hw *hw, enum i40e_debug_mask mask, void *desc,
                   void *buffer, u16 buf_len)
 {
        struct i40e_aq_desc *aq_desc = (struct i40e_aq_desc *)desc;
-       u16 len = le16_to_cpu(aq_desc->datalen);
+       u16 len;
        u8 *buf = (u8 *)buffer;
        u16 i = 0;
 
        if ((!(mask & hw->debug_mask)) || (desc == NULL))
                return;
 
+       len = le16_to_cpu(aq_desc->datalen);
+
        i40e_debug(hw, mask,
                   "AQ CMD: opcode 0x%04X, flags 0x%04X, datalen 0x%04X, retval 0x%04X\n",
                   le16_to_cpu(aq_desc->opcode),