Re: [bpf-next v7 1/5] bpf: Move constants blinding from JIT to verifier

[kernel test robot <lkp@intel.com>]

Hi Xu,

kernel test robot noticed the following build errors:

[auto build test ERROR on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Xu-Kuohai/bpf-Move-constants-blinding-from-JIT-to-verifier/20260307-181538
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20260307103949.2340104-2-xukuohai%40huaweicloud.com
patch subject: [bpf-next v7 1/5] bpf: Move constants blinding from JIT to verifier
config: riscv-randconfig-002-20260307 (https://download.01.org/0day-ci/archive/20260308/202603080126.Lh5uvLLo-lkp@intel.com/config)
compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project c32caeec8158d634bb71ab8911a6031248b9fc47)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260308/202603080126.Lh5uvLLo-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/202603080126.Lh5uvLLo-lkp@intel.com/

All errors (new ones prefixed by >>):

>> kernel/bpf/verifier.c:23100:9: error: call to undeclared function 'bpf_jit_blind_constants'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    23100 |                 err = bpf_jit_blind_constants(env);
          |                       ^
   1 error generated.


vim +/bpf_jit_blind_constants +23100 kernel/bpf/verifier.c

 23087	
 23088	static int fixup_call_args(struct bpf_verifier_env *env)
 23089	{
 23090	#ifndef CONFIG_BPF_JIT_ALWAYS_ON
 23091		struct bpf_prog *prog = env->prog;
 23092		struct bpf_insn *insn = prog->insnsi;
 23093		bool has_kfunc_call = bpf_prog_has_kfunc_call(prog);
 23094		int i, depth;
 23095	#endif
 23096		int err = 0;
 23097	
 23098		if (env->prog->jit_requested &&
 23099		    !bpf_prog_is_offloaded(env->prog->aux)) {
 23100			err = bpf_jit_blind_constants(env);
 23101			if (err)
 23102				return err;
 23103			err = jit_subprogs(env);
 23104			if (err == 0)
 23105				return 0;
 23106			if (err == -EFAULT)
 23107				return err;
 23108		}
 23109	#ifndef CONFIG_BPF_JIT_ALWAYS_ON
 23110		if (has_kfunc_call) {
 23111			verbose(env, "calling kernel functions are not allowed in non-JITed programs\n");
 23112			return -EINVAL;
 23113		}
 23114		if (env->subprog_cnt > 1 && env->prog->aux->tail_call_reachable) {
 23115			/* When JIT fails the progs with bpf2bpf calls and tail_calls
 23116			 * have to be rejected, since interpreter doesn't support them yet.
 23117			 */
 23118			verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n");
 23119			return -EINVAL;
 23120		}
 23121		for (i = 0; i < prog->len; i++, insn++) {
 23122			if (bpf_pseudo_func(insn)) {
 23123				/* When JIT fails the progs with callback calls
 23124				 * have to be rejected, since interpreter doesn't support them yet.
 23125				 */
 23126				verbose(env, "callbacks are not allowed in non-JITed programs\n");
 23127				return -EINVAL;
 23128			}
 23129	
 23130			if (!bpf_pseudo_call(insn))
 23131				continue;
 23132			depth = get_callee_stack_depth(env, insn, i);
 23133			if (depth < 0)
 23134				return depth;
 23135			bpf_patch_call_args(insn, depth);
 23136		}
 23137		err = 0;
 23138	#endif
 23139		return err;
 23140	}
 23141	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki