Re: [akpm-mm:mm-nonmm-unstable 77/129] arch/loongarch/net/bpf_jit.c:1322:7: error: call to undeclared function '__bpf_address_lookup'; ISO C99 and later do not support implicit function declarations

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 14 Jan 2026 01:37:38 +0800 kernel test robot <lkp@intel.com> wrote:

> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-nonmm-unstable
> head:   01c8de771f4a779caac5d841b1cb2207ac23330a
> commit: 0f1766dc93f077061bf42cc6222bb2ade96422a4 [77/129] kallsyms/bpf: rename __bpf_address_lookup() to bpf_address_lookup()
> config: loongarch-allmodconfig (https://download.01.org/0day-ci/archive/20260114/202601140159.I4b0kwpE-lkp@intel.com/config)
> compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260114/202601140159.I4b0kwpE-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202601140159.I4b0kwpE-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
> >> arch/loongarch/net/bpf_jit.c:1322:7: error: call to undeclared function '__bpf_address_lookup'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>     1322 |         if (!__bpf_address_lookup((unsigned long)ip, &size, &offset, namebuf))
>          |              ^
>    arch/loongarch/net/bpf_jit.c:1322:7: note: did you mean 'bpf_address_lookup'?
>    include/linux/filter.h:1378:5: note: 'bpf_address_lookup' declared here
>     1378 | int bpf_address_lookup(unsigned long addr, unsigned long *size,
>          |     ^
>    1 error generated.

Thanks.  Presumably this:

--- a/arch/loongarch/net/bpf_jit.c~kallsyms-bpf-rename-__bpf_address_lookup-to-bpf_address_lookup-fix
+++ a/arch/loongarch/net/bpf_jit.c
@@ -1319,7 +1319,7 @@ int bpf_arch_text_poke(void *ip, enum bp
 	/* Only poking bpf text is supported. Since kernel function entry
 	 * is set up by ftrace, we rely on ftrace to poke kernel functions.
 	 */
-	if (!__bpf_address_lookup((unsigned long)ip, &size, &offset, namebuf))
+	if (!bpf_address_lookup((unsigned long)ip, &size, &offset, namebuf))
 		return -ENOTSUPP;
 
 	image = ip - offset;
_