tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   81214a573d19ae2fa5b528286ba23cd1cb17feec
commit: 080ae5bb93cd83604c93417bea6a6434e4eb2aca [5006/5092] kprobes,lib: kretprobe scalability improvement
config: hexagon-randconfig-r026-20221102
compiler: clang version 15.0.4 (https://github.com/llvm/llvm-project 5c68a1cb123161b54b72ce90e7975d95a8eaf2a4)
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/next/linux-next.git/commit/?id=080ae5bb93cd83604c93417bea6a6434e4eb2aca
        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 080ae5bb93cd83604c93417bea6a6434e4eb2aca
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash

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

Note: the linux-next/master HEAD 81214a573d19ae2fa5b528286ba23cd1cb17feec builds fine.
      It may have been fixed somewhere.

All errors (new ones prefixed by >>):

>> lib/objpool.c:378:3: error: call to undeclared function 'prefetch'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
                   prefetch(&ents[id]);
                   ^
   1 error generated.


vim +/prefetch +378 lib/objpool.c

   364	
   365	/* try to retrieve object from slot */
   366	static inline void *__objpool_try_get_slot(struct objpool_slot *os)
   367	{
   368		uint32_t *ages = SLOT_AGES(os);
   369		void **ents = SLOT_ENTS(os);
   370		/* do memory load of os_head to local head */
   371		uint32_t head = smp_load_acquire(&os->os_head);
   372	
   373		/* loop if slot isn't empty */
   374		while (head != READ_ONCE(os->os_tail)) {
   375			uint32_t id = head & os->os_mask, prev = head;
   376	
   377			/* do prefetching of object ents */
 > 378			prefetch(&ents[id]);
   379	
   380			/*
   381			 * check whether this item was ready for retrieval ? There's
   382			 * possibility * in theory * we might retrieve wrong object,
   383			 * in case ages[id] overflows when current task is sleeping,
   384			 * but it will take very very long to overflow an uint32_t
   385			 */
   386			if (smp_load_acquire(&ages[id]) == head) {
   387				/* node must have been udpated by push() */
   388				void *node = READ_ONCE(ents[id]);
   389				/* commit and move forward head of the slot */
   390				if (try_cmpxchg_release(&os->os_head, &head, head + 1))
   391					return node;
   392			}
   393	
   394			/* re-load head from memory continue trying */
   395			head = READ_ONCE(os->os_head);
   396			/*
   397			 * head stays unchanged, so it's very likely current pop()
   398			 * just preempted/interrupted an ongoing push() operation
   399			 */
   400			if (head == prev)
   401				break;
   402		}
   403	
   404		return NULL;
   405	}
   406	

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp