tree:   https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git bpf/tracing_multi
head:   3f77a2c51293ea19f1ce6a9b06b9fa394beecd13
commit: fb3e0f80af089fc89a36ad479f7adfc4dd3aa9fb [11/18] bpf: Add support to attach program to multiple trampolines
config: mips-allyesconfig
compiler: mips-linux-gcc (GCC) 12.1.0
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/jolsa/perf.git/commit/?id=fb3e0f80af089fc89a36ad479f7adfc4dd3aa9fb
        git remote add jolsa-perf https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
        git fetch --no-tags jolsa-perf bpf/tracing_multi
        git checkout fb3e0f80af089fc89a36ad479f7adfc4dd3aa9fb
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash kernel/

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

All errors (new ones prefixed by >>):

   kernel/bpf/trampoline.c: In function 'bpf_trampoline_lookup':
>> kernel/bpf/trampoline.c:259:13: error: implicit declaration of function 'key_in_multi_trampoline' [-Werror=implicit-function-declaration]
     259 |         if (key_in_multi_trampoline(key))
         |             ^~~~~~~~~~~~~~~~~~~~~~~
   kernel/bpf/trampoline.c: At top level:
>> kernel/bpf/trampoline.c:1056:13: error: conflicting types for 'key_in_multi_trampoline'; have 'bool(u64)' {aka '_Bool(long long unsigned int)'}
    1056 | static bool key_in_multi_trampoline(u64 key)
         |             ^~~~~~~~~~~~~~~~~~~~~~~
   kernel/bpf/trampoline.c:259:13: note: previous implicit declaration of 'key_in_multi_trampoline' with type 'int()'
     259 |         if (key_in_multi_trampoline(key))
         |             ^~~~~~~~~~~~~~~~~~~~~~~
   kernel/bpf/trampoline.c:1056:13: warning: 'key_in_multi_trampoline' defined but not used [-Wunused-function]
    1056 | static bool key_in_multi_trampoline(u64 key)
         |             ^~~~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/key_in_multi_trampoline +259 kernel/bpf/trampoline.c

   252	
   253	static struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
   254	{
   255		struct bpf_trampoline *tr = NULL;
   256		struct hlist_head *head;
   257	
   258		mutex_lock(&trampoline_mutex);
 > 259		if (key_in_multi_trampoline(key))
   260			goto out;
   261		tr = __bpf_trampoline_lookup(key);
   262		if (tr) {
   263			refcount_inc(&tr->refcnt);
   264			goto out;
   265		}
   266		tr = bpf_trampoline_alloc();
   267		if (!tr)
   268			goto out;
   269		tr->key = key;
   270		head = &trampoline_table[hash_64(key, TRAMPOLINE_HASH_BITS)];
   271		hlist_add_head(&tr->hlist, head);
   272	out:
   273		mutex_unlock(&trampoline_mutex);
   274		return tr;
   275	}
   276	

-- 
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https://01.org/lkp