[ast-bpf:relo_core 5/11] kernel/bpf/btf.c:6498:13: warning: variable 'err' set but not used

From: kernel test robot
Date: Fri Sep 17 2021 - 22:13:39 EST


tree: https://git.kernel.org/pub/scm/linux/kernel/git/ast/bpf.git relo_core
head: 35a0182c26565e1db43f99a764834bff8a2e4202
commit: 98beca424883749fbcf9f244bb26c96ed3102502 [5/11] bpf: Add bpf_core_add_cands() and wire it into bpf_core_apply_relo_insn().
config: riscv-randconfig-r042-20210916 (attached as .config)
compiler: riscv32-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://git.kernel.org/pub/scm/linux/kernel/git/ast/bpf.git/commit/?id=98beca424883749fbcf9f244bb26c96ed3102502
git remote add ast-bpf https://git.kernel.org/pub/scm/linux/kernel/git/ast/bpf.git
git fetch --no-tags ast-bpf relo_core
git checkout 98beca424883749fbcf9f244bb26c96ed3102502
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=riscv

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

All warnings (new ones prefixed by >>):

kernel/bpf/btf.c: In function 'btf_seq_show':
kernel/bpf/btf.c:5877:29: warning: function 'btf_seq_show' might be a candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
5877 | seq_vprintf((struct seq_file *)show->target, fmt, args);
| ^~~~~~~~
kernel/bpf/btf.c: In function 'btf_snprintf_show':
kernel/bpf/btf.c:5914:9: warning: function 'btf_snprintf_show' might be a candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
5914 | len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
| ^~~
kernel/bpf/btf.c: In function '____bpf_core_apply_relo':
>> kernel/bpf/btf.c:6498:13: warning: variable 'err' set but not used [-Wunused-but-set-variable]
6498 | int err;
| ^~~


vim +/err +6498 kernel/bpf/btf.c

6491
6492 BPF_CALL_5(bpf_core_apply_relo, int, btf_fd, struct bpf_core_relo_desc *, relo,
6493 int, relo_sz, void *, insn, int, flags)
6494 {
6495 struct bpf_core_cand_list *cands = NULL;
6496 struct bpf_core_relo core_relo = {};
6497 struct btf *btf;
> 6498 int err;
6499
6500 if (flags)
6501 return -EINVAL;
6502
6503 if (sizeof(*relo) != relo_sz)
6504 return -EINVAL;
6505 btf = btf_get_by_fd(btf_fd);
6506 if (IS_ERR(btf))
6507 return PTR_ERR(btf);
6508 if (btf_is_kernel(btf)) {
6509 btf_put(btf);
6510 return -EACCES;
6511 }
6512 if (relo->kind != BPF_CORE_TYPE_ID_LOCAL) {
6513 cands = bpf_core_find_cands(btf, relo->type_id);
6514 if (IS_ERR(cands)) {
6515 btf_put(btf);
6516 printk("target candidate search failed for %d\n",
6517 relo->type_id);
6518 return PTR_ERR(cands);
6519 }
6520 }
6521 core_relo.type_id = relo->type_id;
6522 core_relo.access_str_off = relo->access_str_off;
6523 core_relo.kind = relo->kind;
6524 err = bpf_core_apply_relo_insn("prog_name", insn, 0, &core_relo, 0, btf, cands);
6525 btf_put(btf);
6526 return 0;
6527 }
6528

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

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