tree: https://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git libnvdimm-for-next head: 4f2e6ecbd1cb397d65ead8aab4fd4d05fcbfeaff commit: 45d0fd3c767f81356f880be9a8893bb12a39488a [49/56] mm, dev_pagemap: introduce CONFIG_DEV_PAGEMAP_OPS config: x86_64-randconfig-g0-04011906 (attached as .config) compiler: gcc-4.9 (Debian 4.9.4-2) 4.9.4 reproduce: git checkout 45d0fd3c767f81356f880be9a8893bb12a39488a # save the attached .config to linux build tree make ARCH=x86_64 All errors (new ones prefixed by >>): drivers//dax/super.c: In function 'fs_dax_claim_bdev': drivers//dax/super.c:207:2: error: implicit declaration of function 'blk_queue_dax' [-Werror=implicit-function-declaration] if (!blk_queue_dax(bdev->bd_queue)) ^ dax_dev = fs_dax_get_by_host(bdev->bd_disk->disk_name); ^ cc1: some warnings being treated as errors vim +209 drivers//dax/super.c b42158bb Dan Williams 2018-03-29 202 b42158bb Dan Williams 2018-03-29 203 struct dax_device *fs_dax_claim_bdev(struct block_device *bdev, void *owner) b42158bb Dan Williams 2018-03-29 204 { b42158bb Dan Williams 2018-03-29 205 struct dax_device *dax_dev; b42158bb Dan Williams 2018-03-29 206 b42158bb Dan Williams 2018-03-29 @207 if (!blk_queue_dax(bdev->bd_queue)) b42158bb Dan Williams 2018-03-29 208 return NULL; b42158bb Dan Williams 2018-03-29 @209 dax_dev = fs_dax_get_by_host(bdev->bd_disk->disk_name); b42158bb Dan Williams 2018-03-29 210 if (dax_dev->ops->fs_claim) b42158bb Dan Williams 2018-03-29 211 return dax_dev->ops->fs_claim(dax_dev, owner); b42158bb Dan Williams 2018-03-29 212 else b42158bb Dan Williams 2018-03-29 213 return fs_dax_claim(dax_dev, owner); b42158bb Dan Williams 2018-03-29 214 } b42158bb Dan Williams 2018-03-29 215 EXPORT_SYMBOL_GPL(fs_dax_claim_bdev); b42158bb Dan Williams 2018-03-29 216 :::::: The code at line 209 was first introduced by commit :::::: b42158bb23c9db316c12e3b3845ef01d41013314 dax, dm: introduce ->fs_{claim,release}() dax_device infrastructure :::::: TO: Dan Williams <dan.j.williams(a)intel.com&gt; :::::: CC: Dan Williams <dan.j.williams(a)intel.com&gt; --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation