Hi Min,

First bad commit (maybe != root cause):

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   5833291ab6de9c3e2374336b51c814e515e8f3a5
commit: a1867f85e06edacd82956d3422caa2b9074f4321 mfd: Add Renesas Synchronization Management Unit (SMU) support
date:   4 months ago
config: powerpc-randconfig-c024-20211012 (attached as .config)
compiler: powerpc-linux-gcc (GCC) 11.2.0
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
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a1867f85e06edacd82956d3422caa2b9074f4321
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout a1867f85e06edacd82956d3422caa2b9074f4321
        # save the attached .config to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=powerpc SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   powerpc-linux-ld: warning: orphan section `.init.plt' from `drivers/mfd/rsmu_core.o' being placed in section `.init.plt'
>> powerpc-linux-ld: warning: orphan section `.ftrace.tramp' from `drivers/mfd/rsmu_core.o' being placed in section `.ftrace.tramp'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fb_helper_set_suspend':
   (.text+0x424): undefined reference to `fb_set_suspend'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fb_helper_resume_worker':
   drm_fb_helper.c:(.text+0x4b0): undefined reference to `fb_set_suspend'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fb_helper_unregister_fbi':
   (.text+0x818): undefined reference to `unregister_framebuffer'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fb_helper_fini':
   (.text+0x9b8): undefined reference to `fb_dealloc_cmap'
   powerpc-linux-ld: (.text+0x9d8): undefined reference to `framebuffer_release'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fb_helper_sys_read':
   (.text+0xbe8): undefined reference to `fb_sys_read'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fb_helper_alloc_fbi':
   (.text+0x34f8): undefined reference to `framebuffer_alloc'
   powerpc-linux-ld: (.text+0x3554): undefined reference to `fb_alloc_cmap'
   powerpc-linux-ld: (.text+0x3618): undefined reference to `fb_dealloc_cmap'
   powerpc-linux-ld: (.text+0x3674): undefined reference to `framebuffer_release'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `__drm_fb_helper_initial_config_and_unlock':
   drm_fb_helper.c:(.text+0x37b0): undefined reference to `register_framebuffer'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fb_helper_set_suspend_unlocked':
   (.text+0x4518): undefined reference to `fb_set_suspend'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fb_helper_generic_probe':
   drm_fb_helper.c:(.text+0x58f8): undefined reference to `fb_deferred_io_init'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fb_helper_sys_write':
   (.text+0x644c): undefined reference to `fb_sys_write'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fb_helper_sys_fillrect':
   (.text+0x6534): undefined reference to `sys_fillrect'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fb_helper_sys_copyarea':
   (.text+0x65b4): undefined reference to `sys_copyarea'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fb_helper_sys_imageblit':
   (.text+0x6634): undefined reference to `sys_imageblit'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fb_helper_cfb_fillrect':
   (.text+0x66b4): undefined reference to `cfb_fillrect'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fb_helper_cfb_copyarea':
   (.text+0x6734): undefined reference to `cfb_copyarea'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fb_helper_cfb_imageblit':
   (.text+0x67b4): undefined reference to `cfb_imageblit'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fbdev_fb_imageblit':
   drm_fb_helper.c:(.text+0x6c30): undefined reference to `cfb_imageblit'
   powerpc-linux-ld: drm_fb_helper.c:(.text+0x6c58): undefined reference to `sys_imageblit'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fbdev_fb_copyarea':
   drm_fb_helper.c:(.text+0x6d30): undefined reference to `cfb_copyarea'
   powerpc-linux-ld: drm_fb_helper.c:(.text+0x6d58): undefined reference to `sys_copyarea'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fbdev_fb_fillrect':
   drm_fb_helper.c:(.text+0x6e30): undefined reference to `cfb_fillrect'
   powerpc-linux-ld: drm_fb_helper.c:(.text+0x6e58): undefined reference to `sys_fillrect'
   powerpc-linux-ld: drivers/gpu/drm/drm_fb_helper.o: in function `drm_fbdev_cleanup':
   drm_fb_helper.c:(.text+0x734c): undefined reference to `fb_deferred_io_cleanup'

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org