[Intel-wired-lan] [PATCH v1 iwl-net] igc: fix null pointer dereference in igc_eeprom_test() on NVM-less devices

[Kohei Enju]

On devices without NVM, hw->nvm.ops.validate is set to NULL, therefore
functions that perform EEPROM-related operations such as
igc_ethtool_set_eeprom() and igc_probe() check for NVM presence in
advance. However igc_eeprom_test() unconditionally calls
hw->nvm.ops.validate(), potentially causing a null pointer dereference.

NVM-less devices may not be common but possible, so add NULL check
before calling hw->nvm.ops.validate().

Fixes: f026d8ca2904 ("igc: add support to eeprom, registers and link 
self-tests")
Signed-off-by: Kohei Enju <ko...@enjuk.jp>
---
 drivers/net/ethernet/intel/igc/igc_diag.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_diag.c 
b/drivers/net/ethernet/intel/igc/igc_diag.c
index a43d7244ee70..973d26a5a6c9 100644
--- a/drivers/net/ethernet/intel/igc/igc_diag.c
+++ b/drivers/net/ethernet/intel/igc/igc_diag.c
@@ -158,7 +158,7 @@ bool igc_eeprom_test(struct igc_adapter *adapter, u64 *data)
 
        *data = 0;
 
-       if (hw->nvm.ops.validate(hw) != IGC_SUCCESS) {
+       if (hw->nvm.ops.validate && hw->nvm.ops.validate(hw) != IGC_SUCCESS) {
                *data = 1;
                return false;
        }
-- 
2.51.0