[arm:zii 70/161] drivers/net/phy/phylink.c:1287 phylink_set_pcs() error: we previously assumed 'pcs' could be null (see line 1283)

[Dan Carpenter]

tree:   git://git.armlinux.org.uk/~rmk/linux-arm.git zii
head:   1c86335a03ee0102daaefede1fb25cdbb367b14c
commit: 8eca4525ad01e4504dba39f4783f9d5885243941 [70/161] net: phylink: add mac_select_pcs() method to phylink_mac_ops
config: s390-randconfig-m031-20211124 (https://download.01.org/0day-ci/archive/20211125/202111252259.X7Tr9l1K-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 11.2.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp at intel.com>
Reported-by: Dan Carpenter <dan.carpenter at oracle.com>

New smatch warnings:
drivers/net/phy/phylink.c:1287 phylink_set_pcs() error: we previously assumed 'pcs' could be null (see line 1283)

Old smatch warnings:
drivers/net/phy/phylink.c:850 phylink_change_inband_advert() error: we previously assumed 'pl->pcs_ops' could be null (see line 833)

vim +/pcs +1287 drivers/net/phy/phylink.c

7137e18f6f889a Russell King          2020-07-21  1274  void phylink_set_pcs(struct phylink *pl, struct phylink_pcs *pcs)
4c0d6d3a7a81fc Russell King          2020-03-30  1275  {
b01e3d443ba5bd Russell King (Oracle  2021-11-22  1276) 	if (pl->config->legacy_pre_march2020 && pl->pcs && !pcs) {
b01e3d443ba5bd Russell King (Oracle  2021-11-22  1277) 		phylink_warn(pl,
b01e3d443ba5bd Russell King (Oracle  2021-11-22  1278) 			     "Removing PCS is not supported in a legacy driver");
b01e3d443ba5bd Russell King (Oracle  2021-11-22  1279) 		return;
b01e3d443ba5bd Russell King (Oracle  2021-11-22  1280) 	}
b01e3d443ba5bd Russell King (Oracle  2021-11-22  1281) 
7137e18f6f889a Russell King          2020-07-21  1282  	pl->pcs = pcs;
b01e3d443ba5bd Russell King (Oracle  2021-11-22 @1283) 	pl->pcs_ops = pcs ? pcs->ops : NULL;
                                                                      ^^^
Check for NULL

8eca4525ad01e4 Russell King (Oracle  2021-10-07  1284) 
8eca4525ad01e4 Russell King (Oracle  2021-10-07  1285) 	if (!pl->phylink_disable_state &&
8eca4525ad01e4 Russell King (Oracle  2021-10-07  1286) 	    pl->cfg_link_an_mode == MLO_AN_INBAND) {
8eca4525ad01e4 Russell King (Oracle  2021-10-07 @1287) 		if (pl->config->pcs_poll || pcs->poll)
                                                                                            ^^^^^^^^^
Unchecked dereference

8eca4525ad01e4 Russell King (Oracle  2021-10-07  1288) 			mod_timer(&pl->link_poll, jiffies + HZ);
8eca4525ad01e4 Russell King (Oracle  2021-10-07  1289) 		else
8eca4525ad01e4 Russell King (Oracle  2021-10-07  1290) 			del_timer(&pl->link_poll);
8eca4525ad01e4 Russell King (Oracle  2021-10-07  1291) 	}
4c0d6d3a7a81fc Russell King          2020-03-30  1292  }

---
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