Re: [PATCH v2 bpf-next 4/4] bpf: Add kernel module with user mode driver that populates bpffs.

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

[-- Attachment #1: Type: text/plain, Size: 3160 bytes --]

Hi Alexei,

I love your patch! Yet something to improve:

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

url:    https://github.com/0day-ci/linux/commits/Alexei-Starovoitov/bpf-Populate-bpffs-with-map-and-prog-iterators/20200717-124311
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: x86_64-allyesconfig (attached as .config)
compiler: gcc-9 (Debian 9.3.0-14) 9.3.0
reproduce (this is a W=1 build):
        # save the attached .config to linux build tree
        make W=1 ARCH=x86_64 

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

All error/warnings (new ones prefixed by >>):

>> make[4]: *** No rule to make target 'kernel/bpf/preload/../../tools/lib/bpf/bpf.c', needed by 'kernel/bpf/preload/../../tools/lib/bpf/bpf.o'.
>> make[4]: *** No rule to make target 'kernel/bpf/preload/../../tools/lib/bpf/libbpf.c', needed by 'kernel/bpf/preload/../../tools/lib/bpf/libbpf.o'.
>> make[4]: *** No rule to make target 'kernel/bpf/preload/../../tools/lib/bpf/btf.c', needed by 'kernel/bpf/preload/../../tools/lib/bpf/btf.o'.
>> make[4]: *** No rule to make target 'kernel/bpf/preload/../../tools/lib/bpf/libbpf_errno.c', needed by 'kernel/bpf/preload/../../tools/lib/bpf/libbpf_errno.o'.
>> make[4]: *** No rule to make target 'kernel/bpf/preload/../../tools/lib/bpf/str_error.c', needed by 'kernel/bpf/preload/../../tools/lib/bpf/str_error.o'.
>> make[4]: *** No rule to make target 'kernel/bpf/preload/../../tools/lib/bpf/hashmap.c', needed by 'kernel/bpf/preload/../../tools/lib/bpf/hashmap.o'.
>> make[4]: *** No rule to make target 'kernel/bpf/preload/../../tools/lib/bpf/libbpf_probes.c', needed by 'kernel/bpf/preload/../../tools/lib/bpf/libbpf_probes.o'.
   make[4]: Target '__build' not remade because of errors.
--
   kernel/bpf/preload/bpf_preload_kern.c: In function 'do_preload':
>> kernel/bpf/preload/bpf_preload_kern.c:16:14: warning: variable 'tgid' set but not used [-Wunused-but-set-variable]
      16 |  struct pid *tgid;
         |              ^~~~

vim +/tgid +16 kernel/bpf/preload/bpf_preload_kern.c

    12	
    13	static int do_preload(struct bpf_preload_info *obj)
    14	{
    15		int magic = BPF_PRELOAD_START;
  > 16		struct pid *tgid;
    17		loff_t pos = 0;
    18		int i, err;
    19		ssize_t n;
    20	
    21		err = fork_usermode_driver(&bpf_preload_ops.info);
    22		if (err)
    23			return err;
    24		tgid = bpf_preload_ops.info.tgid;
    25	
    26		/* send the start magic to let UMD proceed with loading BPF progs */
    27		n = kernel_write(bpf_preload_ops.info.pipe_to_umh,
    28				 &magic, sizeof(magic), &pos);
    29		if (n != sizeof(magic))
    30			return -EPIPE;
    31	
    32		/* receive bpf_link IDs and names from UMD */
    33		pos = 0;
    34		for (i = 0; i < BPF_PRELOAD_LINKS; i++) {
    35			n = kernel_read(bpf_preload_ops.info.pipe_from_umh,
    36					&obj[i], sizeof(*obj), &pos);
    37			if (n != sizeof(*obj))
    38				return -EPIPE;
    39		}
    40		return 0;
    41	}
    42	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 75279 bytes --]