Re: [PATCH trace/for-next 3/3] bpf: ensure RCU Tasks Trace GP for sleepable raw tracepoint BPF links

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

Hi Andrii,

kernel test robot noticed the following build errors:

[auto build test ERROR on trace/for-next]

url:    https://github.com/intel-lab-lkp/linux/commits/Andrii-Nakryiko/bpf-decouple-BPF-link-attach-hook-and-BPF-program-sleepable-semantics/20241101-051131
base:   https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace for-next
patch link:    https://lore.kernel.org/r/20241031210938.1696639-3-andrii%40kernel.org
patch subject: [PATCH trace/for-next 3/3] bpf: ensure RCU Tasks Trace GP for sleepable raw tracepoint BPF links
config: i386-buildonly-randconfig-001-20241101 (https://download.01.org/0day-ci/archive/20241101/202411011258.IemsLYSp-lkp@intel.com/config)
compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241101/202411011258.IemsLYSp-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/202411011258.IemsLYSp-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from kernel/bpf/syscall.c:4:
   In file included from include/linux/bpf.h:21:
   In file included from include/linux/kallsyms.h:13:
   In file included from include/linux/mm.h:2213:
   include/linux/vmstat.h:518:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     518 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
>> kernel/bpf/syscall.c:3866:5: error: call to undeclared function 'tracepoint_is_faultable'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    3866 |                                 tracepoint_is_faultable(btp->tp));
         |                                 ^
   kernel/bpf/syscall.c:5876:30: warning: bitwise operation between different enumeration types ('enum bpf_arg_type' and 'enum bpf_type_flag') [-Wenum-enum-conversion]
    5876 |         .arg2_type      = ARG_PTR_TO_MEM | MEM_RDONLY,
         |                           ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~
   kernel/bpf/syscall.c:5926:41: warning: bitwise operation between different enumeration types ('enum bpf_arg_type' and 'enum bpf_type_flag') [-Wenum-enum-conversion]
    5926 |         .arg4_type      = ARG_PTR_TO_FIXED_SIZE_MEM | MEM_UNINIT | MEM_ALIGNED,
         |                           ~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~
   3 warnings and 1 error generated.


vim +/tracepoint_is_faultable +3866 kernel/bpf/syscall.c

  3818	
  3819	static int bpf_raw_tp_link_attach(struct bpf_prog *prog,
  3820					  const char __user *user_tp_name, u64 cookie)
  3821	{
  3822		struct bpf_link_primer link_primer;
  3823		struct bpf_raw_tp_link *link;
  3824		struct bpf_raw_event_map *btp;
  3825		const char *tp_name;
  3826		char buf[128];
  3827		int err;
  3828	
  3829		switch (prog->type) {
  3830		case BPF_PROG_TYPE_TRACING:
  3831		case BPF_PROG_TYPE_EXT:
  3832		case BPF_PROG_TYPE_LSM:
  3833			if (user_tp_name)
  3834				/* The attach point for this category of programs
  3835				 * should be specified via btf_id during program load.
  3836				 */
  3837				return -EINVAL;
  3838			if (prog->type == BPF_PROG_TYPE_TRACING &&
  3839			    prog->expected_attach_type == BPF_TRACE_RAW_TP) {
  3840				tp_name = prog->aux->attach_func_name;
  3841				break;
  3842			}
  3843			return bpf_tracing_prog_attach(prog, 0, 0, 0);
  3844		case BPF_PROG_TYPE_RAW_TRACEPOINT:
  3845		case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
  3846			if (strncpy_from_user(buf, user_tp_name, sizeof(buf) - 1) < 0)
  3847				return -EFAULT;
  3848			buf[sizeof(buf) - 1] = 0;
  3849			tp_name = buf;
  3850			break;
  3851		default:
  3852			return -EINVAL;
  3853		}
  3854	
  3855		btp = bpf_get_raw_tracepoint(tp_name);
  3856		if (!btp)
  3857			return -ENOENT;
  3858	
  3859		link = kzalloc(sizeof(*link), GFP_USER);
  3860		if (!link) {
  3861			err = -ENOMEM;
  3862			goto out_put_btp;
  3863		}
  3864		bpf_link_init_sleepable(&link->link, BPF_LINK_TYPE_RAW_TRACEPOINT,
  3865					&bpf_raw_tp_link_lops, prog,
> 3866					tracepoint_is_faultable(btp->tp));
  3867		link->btp = btp;
  3868		link->cookie = cookie;
  3869	
  3870		err = bpf_link_prime(&link->link, &link_primer);
  3871		if (err) {
  3872			kfree(link);
  3873			goto out_put_btp;
  3874		}
  3875	
  3876		err = bpf_probe_register(link->btp, link);
  3877		if (err) {
  3878			bpf_link_cleanup(&link_primer);
  3879			goto out_put_btp;
  3880		}
  3881	
  3882		return bpf_link_settle(&link_primer);
  3883	
  3884	out_put_btp:
  3885		bpf_put_raw_tracepoint(btp);
  3886		return err;
  3887	}
  3888	

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