tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 8dca2cd055ffb78b37f52f0bf0bd20c249619c4d commit: e972c2511967181d955f74181d74438e26b2e797 [4341/4499] mm/early_ioremap: add prototype for early_memremap_pgprot_adjust config: x86_64-randconfig-a002-20210523 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project e84a9b9bb3051c35dea993cdad7b3d2575638f85) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu # 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 e972c2511967181d955f74181d74438e26b2e797 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross 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 warnings (new ones prefixed by >>): In file included from drivers/gpu/drm/vgem/vgem_drv.c:33: In file included from include/linux/dma-buf.h:16: In file included from include/linux/dma-buf-map.h:9: In file included from include/linux/io.h:13: In file included from arch/x86/include/asm/io.h:44: In file included from ./arch/x86/include/generated/asm/early_ioremap.h:1: In file included from include/asm-generic/early_ioremap.h:6: arch/x86/include/asm/fixmap.h:103:48: error: use of undeclared identifier 'NR_CPUS' FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1, ^ DMA_BIT_MASK(64)); ^~~~~~~~~~~~~~~~ include/linux/dma-mapping.h:76:54: note: expanded from macro 'DMA_BIT_MASK' #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1)) ^ ~~~ 1 warning and 1 error generated. vim +460 drivers/gpu/drm/vgem/vgem_drv.c 502e95c6678505 Zach Reizner 2015-03-04 444 502e95c6678505 Zach Reizner 2015-03-04 445 static int __init vgem_init(void) 502e95c6678505 Zach Reizner 2015-03-04 446 { 502e95c6678505 Zach Reizner 2015-03-04 447 int ret; bcc0ef7f57e51e Daniel Vetter 2020-09-09 448 struct platform_device *pdev; 502e95c6678505 Zach Reizner 2015-03-04 449 bcc0ef7f57e51e Daniel Vetter 2020-09-09 450 pdev = platform_device_register_simple("vgem", -1, NULL, 0); bcc0ef7f57e51e Daniel Vetter 2020-09-09 451 if (IS_ERR(pdev)) bcc0ef7f57e51e Daniel Vetter 2020-09-09 452 return PTR_ERR(pdev); e2aff44868ae60 Laura Abbott 2017-05-04 453 bcc0ef7f57e51e Daniel Vetter 2020-09-09 454 if (!devres_open_group(&pdev->dev, NULL, GFP_KERNEL)) { bcc0ef7f57e51e Daniel Vetter 2020-09-09 455 ret = -ENOMEM; bcc0ef7f57e51e Daniel Vetter 2020-09-09 456 goto out_unregister; 502e95c6678505 Zach Reizner 2015-03-04 457 } 502e95c6678505 Zach Reizner 2015-03-04 458 bcc0ef7f57e51e Daniel Vetter 2020-09-09 459 dma_coerce_mask_and_coherent(&pdev->dev, e2aff44868ae60 Laura Abbott 2017-05-04 @460 DMA_BIT_MASK(64)); bcc0ef7f57e51e Daniel Vetter 2020-09-09 461 bcc0ef7f57e51e Daniel Vetter 2020-09-09 462 vgem_device = devm_drm_dev_alloc(&pdev->dev, &vgem_driver, bcc0ef7f57e51e Daniel Vetter 2020-09-09 463 struct vgem_device, drm); bcc0ef7f57e51e Daniel Vetter 2020-09-09 464 if (IS_ERR(vgem_device)) { bcc0ef7f57e51e Daniel Vetter 2020-09-09 465 ret = PTR_ERR(vgem_device); bcc0ef7f57e51e Daniel Vetter 2020-09-09 466 goto out_devres; bcc0ef7f57e51e Daniel Vetter 2020-09-09 467 } bcc0ef7f57e51e Daniel Vetter 2020-09-09 468 vgem_device->platform = pdev; e2aff44868ae60 Laura Abbott 2017-05-04 469 315f0242aa2b1e Chris Wilson 2017-05-08 470 /* Final step: expose the device/driver to userspace */ 315f0242aa2b1e Chris Wilson 2017-05-08 471 ret = drm_dev_register(&vgem_device->drm, 0); 502e95c6678505 Zach Reizner 2015-03-04 472 if (ret) bcc0ef7f57e51e Daniel Vetter 2020-09-09 473 goto out_devres; 502e95c6678505 Zach Reizner 2015-03-04 474 502e95c6678505 Zach Reizner 2015-03-04 475 return 0; 502e95c6678505 Zach Reizner 2015-03-04 476 bcc0ef7f57e51e Daniel Vetter 2020-09-09 477 out_devres: bcc0ef7f57e51e Daniel Vetter 2020-09-09 478 devres_release_group(&pdev->dev, NULL); d5c04dff24870e Deepak Sharma 2018-10-23 479 out_unregister: bcc0ef7f57e51e Daniel Vetter 2020-09-09 480 platform_device_unregister(pdev); 502e95c6678505 Zach Reizner 2015-03-04 481 return ret; 502e95c6678505 Zach Reizner 2015-03-04 482 } 502e95c6678505 Zach Reizner 2015-03-04 483 :::::: The code at line 460 was first introduced by commit :::::: e2aff44868ae60eccae806d3751077155675c2a4 drm/vgem: Add a dummy platform device :::::: TO: Laura Abbott <labbott(a)redhat.com&gt; :::::: CC: Daniel Vetter <daniel.vetter(a)ffwll.ch&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org