Hi Rasmus,

[FYI, it's a private test report for your RFC patch.]
[auto build test ERROR on linus/master]
[also build test ERROR on v5.11]
[cannot apply to linux/master driver-core/driver-core-testing next-20210224]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Rasmus-Villemoes/background-initramfs-unpacking-and-CONFIG_MODPROBE_PATH/20210224-232842
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git c03c21ba6f4e95e406a1a7b4c34ef334b977c194
config: alpha-randconfig-r002-20210223 (attached as .config)
compiler: alpha-linux-gcc (GCC) 9.3.0
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://github.com/0day-ci/linux/commit/e7d2b5f4883ef07e135fad4e0f2340b116c65b06
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Rasmus-Villemoes/background-initramfs-unpacking-and-CONFIG_MODPROBE_PATH/20210224-232842
        git checkout e7d2b5f4883ef07e135fad4e0f2340b116c65b06
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=alpha 

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

All error/warnings (new ones prefixed by >>):

>> init/initramfs.c:533:42: error: 'CONFIG_INITRAMFS_ASYNC' undeclared here (not in a function); did you mean 'CONFIG_INITRAMFS_SOURCE'?
     533 | static bool __initdata initramfs_async = CONFIG_INITRAMFS_ASYNC;
         |                                          ^~~~~~~~~~~~~~~~~~~~~~
         |                                          CONFIG_INITRAMFS_SOURCE
>> init/initramfs.c:545:6: warning: no previous prototype for '_wait_for_initramfs' [-Wmissing-prototypes]
     545 | void _wait_for_initramfs(const char *caller)
         |      ^~~~~~~~~~~~~~~~~~~


vim +533 init/initramfs.c

   532	
 > 533	static bool __initdata initramfs_async = CONFIG_INITRAMFS_ASYNC;
   534	static int __init initramfs_async_setup(char *str)
   535	{
   536		strtobool(str, &initramfs_async);
   537		return 1;
   538	}
   539	__setup("initramfs_async=", initramfs_async_setup);
   540	
   541	static __initdata struct work_struct initramfs_wrk;
   542	static DECLARE_COMPLETION(initramfs_done);
   543	static bool initramfs_unpack_started;
   544	
 > 545	void _wait_for_initramfs(const char *caller)
   546	{
   547		unsigned long start;
   548	
   549		if (try_wait_for_completion(&initramfs_done))
   550			return;
   551		if (!initramfs_unpack_started) {
   552			/*
   553			 * Something before rootfs_initcall wants to access
   554			 * the filesystem/initramfs. Probably a bug. Make a
   555			 * note, avoid deadlocking the machine, and let the
   556			 * caller's access fail as it used to.
   557			 */
   558			pr_warn_once("wait_for_initramfs() called by %s"
   559				     " before rootfs_initcalls\n", caller);
   560			return;
   561		}
   562	
   563		start = jiffies;
   564		wait_for_completion(&initramfs_done);
   565		pr_info("%s() waited %lu jiffies for initramfs_done\n",
   566			caller, jiffies - start);
   567	}
   568	EXPORT_SYMBOL_GPL(_wait_for_initramfs);
   569	

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