CC: [email protected]
BCC: [email protected]
In-Reply-To: <[email protected]>
References: <[email protected]>
TO: Kumar Kartikeya Dwivedi <[email protected]>
TO: [email protected]
CC: Alexei Starovoitov <[email protected]>
CC: Andrii Nakryiko <[email protected]>
CC: Daniel Borkmann <[email protected]>
CC: "Toke Høiland-Jørgensen" <[email protected]>
CC: Jesper Dangaard Brouer <[email protected]>

Hi Kumar,

Thank you for the patch! Perhaps something to improve:

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

url:    
https://github.com/intel-lab-lkp/linux/commits/Kumar-Kartikeya-Dwivedi/Introduce-typed-pointer-support-in-BPF-maps/20220409-173513
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
:::::: branch date: 4 hours ago
:::::: commit date: 4 hours ago
config: i386-randconfig-m021 
(https://download.01.org/0day-ci/archive/20220409/[email protected]/config)
compiler: gcc-11 (Debian 11.2.0-19) 11.2.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
Reported-by: Dan Carpenter <[email protected]>

smatch warnings:
kernel/bpf/verifier.c:5317 process_kptr_func() warn: passing zero to 'PTR_ERR'

vim +/PTR_ERR +5317 kernel/bpf/verifier.c

b00628b1c7d595 Alexei Starovoitov      2021-07-14  5295  
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5296  static int 
process_kptr_func(struct bpf_verifier_env *env, int regno,
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5297                         
     struct bpf_call_arg_meta *meta)
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5298  {
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5299         struct 
bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5300         struct 
bpf_map_value_off_desc *off_desc;
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5301         struct bpf_map 
*map_ptr = reg->map_ptr;
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5302         u32 kptr_off;
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5303         int ret;
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5304  
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5305         if 
(!tnum_is_const(reg->var_off)) {
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5306                 
verbose(env,
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5307                         
"R%d doesn't have constant offset. kptr has to be at the constant offset\n",
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5308                         
regno);
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5309                 return 
-EINVAL;
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5310         }
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5311         if 
(!map_ptr->btf) {
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5312                 
verbose(env, "map '%s' has to have BTF in order to use bpf_kptr_xchg\n",
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5313                         
map_ptr->name);
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5314                 return 
-EINVAL;
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5315         }
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5316         if 
(!map_value_has_kptrs(map_ptr)) {
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09 @5317                 ret = 
PTR_ERR(map_ptr->kptr_off_tab);
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5318                 if (ret 
== -E2BIG)
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5319                         
verbose(env, "map '%s' has more than %d kptr\n", map_ptr->name,
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5320                         
        BPF_MAP_VALUE_OFF_MAX);
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5321                 else if 
(ret == -EEXIST)
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5322                         
verbose(env, "map '%s' has repeating kptr BTF tags\n", map_ptr->name);
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5323                 else
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5324                         
verbose(env, "map '%s' has no valid kptr\n", map_ptr->name);
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5325                 return 
-EINVAL;
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5326         }
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5327  
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5328         meta->map_ptr = 
map_ptr;
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5329         /* Check access 
for BPF_WRITE */
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5330         meta->raw_mode 
= true;
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5331         ret = 
check_helper_mem_access(env, regno, sizeof(u64), false, meta);
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5332         if (ret < 0)
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5333                 return 
ret;
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5334  
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5335         kptr_off = 
reg->off + reg->var_off.value;
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5336         off_desc = 
bpf_map_kptr_off_contains(map_ptr, kptr_off);
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5337         if (!off_desc) {
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5338                 
verbose(env, "off=%d doesn't point to kptr\n", kptr_off);
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5339                 return 
-EACCES;
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5340         }
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5341         if 
(!(off_desc->flags & BPF_MAP_VALUE_OFF_F_REF)) {
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5342                 
verbose(env, "off=%d kptr isn't referenced kptr\n", kptr_off);
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5343                 return 
-EACCES;
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5344         }
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5345         
meta->kptr_off_desc = off_desc;
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5346         return 0;
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5347  }
dd8be1418d45aa Kumar Kartikeya Dwivedi 2022-04-09  5348  

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp
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