Hi Andrew, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 7204eaa2c1f509066486f488c9dcb065d7484494 commit: a9770eac511ad82390b9f4a3c1728e078c387ac7 [3068/6354] net: mdio: Move MDIO drivers into a new subdirectory config: x86_64-randconfig-a001-20200910 (attached as .config) compiler: gcc-9 (Debian 9.3.0-15) 9.3.0 reproduce (this is a W=1 build): git checkout a9770eac511ad82390b9f4a3c1728e078c387ac7 # save the attached .config to linux build tree make W=1 ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): ld: drivers/net/phy/mdio_devres.o: in function `devm_mdiobus_alloc_size': drivers/net/phy/mdio_devres.c:38: undefined reference to `mdiobus_alloc_size' ld: drivers/net/phy/mdio_devres.o: in function `devm_mdiobus_free': drivers/net/phy/mdio_devres.c:16: undefined reference to `mdiobus_free' ld: drivers/net/phy/mdio_devres.o: in function `__devm_mdiobus_register': drivers/net/phy/mdio_devres.c:87: undefined reference to `__mdiobus_register' ld: drivers/net/phy/mdio_devres.o: in function `devm_mdiobus_unregister': drivers/net/phy/mdio_devres.c:53: undefined reference to `mdiobus_unregister' ld: drivers/net/phy/mdio_devres.o: in function `devm_of_mdiobus_register': drivers/net/phy/mdio_devres.c:120: undefined reference to `of_mdiobus_register' ld: drivers/net/mdio/mdio-mscc-miim.o: in function `mscc_miim_remove': ld: drivers/net/mdio/mdio-mscc-miim.o: in function `mscc_miim_probe': ld: drivers/net/pcs/pcs-xpcs.o: in function `xpcs_read': drivers/net/pcs/pcs-xpcs.c:151: undefined reference to `mdiobus_read' ld: drivers/net/pcs/pcs-xpcs.o: in function `xpcs_write': drivers/net/pcs/pcs-xpcs.c:158: undefined reference to `mdiobus_write' ld: drivers/net/pcs/pcs-xpcs.o: in function `xpcs_read': drivers/net/pcs/pcs-xpcs.c:151: undefined reference to `mdiobus_read' ld: drivers/net/pcs/pcs-xpcs.o: in function `xpcs_write': drivers/net/pcs/pcs-xpcs.c:158: undefined reference to `mdiobus_write' ld: drivers/net/pcs/pcs-xpcs.o: in function `xpcs_read': drivers/net/pcs/pcs-xpcs.c:151: undefined reference to `mdiobus_read' ld: drivers/net/pcs/pcs-xpcs.o: in function `xpcs_write': drivers/net/pcs/pcs-xpcs.c:158: undefined reference to `mdiobus_write' ld: drivers/net/pcs/pcs-xpcs.c:158: undefined reference to `mdiobus_write' ld: drivers/net/pcs/pcs-xpcs.c:158: undefined reference to `mdiobus_write' ld: drivers/net/pcs/pcs-xpcs.c:158: undefined reference to `mdiobus_write' ld: drivers/net/pcs/pcs-xpcs.o: in function `xpcs_read': drivers/net/pcs/pcs-xpcs.c:151: undefined reference to `mdiobus_read' ld: drivers/net/pcs/pcs-xpcs.o: in function `xpcs_write': drivers/net/pcs/pcs-xpcs.c:158: undefined reference to `mdiobus_write' ld: drivers/net/pcs/pcs-xpcs.c:158: undefined reference to `mdiobus_write' ld: drivers/net/pcs/pcs-xpcs.o: in function `xpcs_read': drivers/net/pcs/pcs-xpcs.c:151: undefined reference to `mdiobus_read' ld: drivers/net/pcs/pcs-xpcs.c:151: undefined reference to `mdiobus_read' ld: drivers/net/pcs/pcs-xpcs.c:151: undefined reference to `mdiobus_read' ld: drivers/net/pcs/pcs-xpcs.c:151: undefined reference to `mdiobus_read' ld: drivers/net/pcs/pcs-xpcs.c:151: undefined reference to `mdiobus_read' ld: drivers/net/pcs/pcs-xpcs.o:drivers/net/pcs/pcs-xpcs.c:151: more undefined references to `mdiobus_read' follow # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commi... git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout a9770eac511ad82390b9f4a3c1728e078c387ac7 vim +188 drivers/net/mdio/mdio-mscc-miim.c 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 134 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 135 static int mscc_miim_probe(struct platform_device *pdev) 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 136 { 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 137 struct resource *res; 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 138 struct mii_bus *bus; 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 139 struct mscc_miim_dev *dev; 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 140 int ret; 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 141 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 142 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 143 if (!res) 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 144 return -ENODEV; 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 145 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 146 bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(*dev)); 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 147 if (!bus) 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 148 return -ENOMEM; 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 149 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 150 bus->name = "mscc_miim"; 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 151 bus->read = mscc_miim_read; 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 152 bus->write = mscc_miim_write; 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 153 bus->reset = mscc_miim_reset; 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 154 snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(&pdev->dev)); 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 155 bus->parent = &pdev->dev; 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 156 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 157 dev = bus->priv; 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 158 dev->regs = devm_ioremap_resource(&pdev->dev, res); 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 159 if (IS_ERR(dev->regs)) { 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 160 dev_err(&pdev->dev, "Unable to map MIIM registers\n"); 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 161 return PTR_ERR(dev->regs); 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 162 } 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 163 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 164 res = platform_get_resource(pdev, IORESOURCE_MEM, 1); 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 165 if (res) { 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 166 dev->phy_regs = devm_ioremap_resource(&pdev->dev, res); 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 167 if (IS_ERR(dev->phy_regs)) { 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 168 dev_err(&pdev->dev, "Unable to map internal phy registers\n"); 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 169 return PTR_ERR(dev->phy_regs); 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 170 } 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 171 } 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 172 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 @173 ret = of_mdiobus_register(bus, pdev->dev.of_node); 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 174 if (ret < 0) { 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 175 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret); 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 176 return ret; 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 177 } 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 178 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 179 platform_set_drvdata(pdev, bus); 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 180 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 181 return 0; 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 182 } 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 183 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 184 static int mscc_miim_remove(struct platform_device *pdev) 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 185 { 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 186 struct mii_bus *bus = platform_get_drvdata(pdev); 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 187 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 @188 mdiobus_unregister(bus); 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 189 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 190 return 0; 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 191 } 542671fe4d86ad drivers/net/phy/mdio-mscc-miim.c Alexandre Belloni 2018-05-14 192 :::::: The code at line 188 was first introduced by commit :::::: 542671fe4d86ad42b132d8814b6847ee1414aba6 net: phy: mscc-miim: Add MDIO driver :::::: TO: Alexandre Belloni <alexandre.belloni(a)bootlin.com&gt; :::::: CC: David S. Miller <davem(a)davemloft.net&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org