Re: [bpf-next v8 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/20260309-214106
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20260309140044.2652538-2-xukuohai%40huaweicloud.com
patch subject: [bpf-next v8 1/5] bpf: Move constants blinding from JIT to verifier
config: powerpc64-randconfig-001-20260317 (https://download.01.org/0day-ci/archive/20260317/202603171843.yv0X1mn3-lkp@intel.com/config)
compiler: powerpc64-linux-gcc (GCC) 8.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260317/202603171843.yv0X1mn3-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/202603171843.yv0X1mn3-lkp@intel.com/

All errors (new ones prefixed by >>):

   powerpc64-linux-ld: kernel/bpf/core.o: in function `bpf_jit_blind_constants':
>> kernel/bpf/core.c:1467: undefined reference to `bpf_patch_insn_data'


vim +1467 kernel/bpf/core.c

  1429	
  1430	int bpf_jit_blind_constants(struct bpf_verifier_env *env)
  1431	{
  1432		struct bpf_insn insn_buff[16], aux[2];
  1433		struct bpf_prog *prog = env->prog;
  1434		int insn_delta, insn_cnt;
  1435		struct bpf_insn *insn;
  1436		int i, rewritten;
  1437	
  1438		if (!prog->blinding_requested || prog->blinded)
  1439			return 0;
  1440	
  1441		insn_cnt = prog->len;
  1442		insn = prog->insnsi;
  1443	
  1444		for (i = 0; i < insn_cnt; i++, insn++) {
  1445			if (bpf_pseudo_func(insn)) {
  1446				/* ld_imm64 with an address of bpf subprog is not
  1447				 * a user controlled constant. Don't randomize it,
  1448				 * since it will conflict with jit_subprogs() logic.
  1449				 */
  1450				insn++;
  1451				i++;
  1452				continue;
  1453			}
  1454	
  1455			/* We temporarily need to hold the original ld64 insn
  1456			 * so that we can still access the first part in the
  1457			 * second blinding run.
  1458			 */
  1459			if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
  1460			    insn[1].code == 0)
  1461				memcpy(aux, insn, sizeof(aux));
  1462	
  1463			rewritten = bpf_jit_blind_insn(insn, aux, insn_buff, prog->aux->verifier_zext);
  1464			if (!rewritten)
  1465				continue;
  1466	
> 1467			prog = bpf_patch_insn_data(env, i, insn_buff, rewritten);
  1468			if (!prog)
  1469				return -ENOMEM;
  1470	
  1471			env->prog = prog;
  1472			insn_delta = rewritten - 1;
  1473	
  1474			/* Walk new program and skip insns we just inserted. */
  1475			insn = prog->insnsi + i + insn_delta;
  1476			insn_cnt += insn_delta;
  1477			i        += insn_delta;
  1478		}
  1479	
  1480		prog->blinded = 1;
  1481		return 0;
  1482	}
  1483	#endif /* CONFIG_BPF_JIT */
  1484	

-- 
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https://github.com/intel/lkp-tests/wiki