[bytedance:5.15-velinux 0/92] net/bpf/bpf_dummy_struct_ops.c:36:11: warning: default initialization of an object of type 'typeof ((kattr->test.ctx_in))' (aka 'const unsigned long long') leaves the object uninitialized

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

tree:   https://github.com/bytedance/kernel.git 5.15-velinux
head:   c71e88ad12bfbc44f855b681ef923e1acc2e984a
commit: 4f78bb6527470bdf3309b62e7767279657a265c0 [0/92] bpf: Add dummy BPF STRUCT_OPS for test purpose
config: x86_64-rhel-9.4-rust (https://download.01.org/0day-ci/archive/20250729/202507291249.2TD46HJE-lkp@intel.com/config)
compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project 61529d9e36fa86782a2458e6bdeedf7f376ef4b5)
rustc: rustc 1.58.0 (02072b482 2022-01-11)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250729/202507291249.2TD46HJE-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/202507291249.2TD46HJE-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> net/bpf/bpf_dummy_struct_ops.c:36:11: warning: default initialization of an object of type 'typeof ((kattr->test.ctx_in))' (aka 'const unsigned long long') leaves the object uninitialized [-Wdefault-const-init-var-unsafe]
      36 |         ctx_in = u64_to_user_ptr(kattr->test.ctx_in);
         |                  ^
   include/linux/kernel.h:50:2: note: expanded from macro 'u64_to_user_ptr'
      50 |         typecheck(u64, (x));            \
         |         ^
   include/linux/typecheck.h:11:12: note: expanded from macro 'typecheck'
      11 |         typeof(x) __dummy2; \
         |                   ^
   1 warning generated.


vim +36 net/bpf/bpf_dummy_struct_ops.c

    19	
    20	static struct bpf_dummy_ops_test_args *
    21	dummy_ops_init_args(const union bpf_attr *kattr, unsigned int nr)
    22	{
    23		__u32 size_in;
    24		struct bpf_dummy_ops_test_args *args;
    25		void __user *ctx_in;
    26		void __user *u_state;
    27	
    28		size_in = kattr->test.ctx_size_in;
    29		if (size_in != sizeof(u64) * nr)
    30			return ERR_PTR(-EINVAL);
    31	
    32		args = kzalloc(sizeof(*args), GFP_KERNEL);
    33		if (!args)
    34			return ERR_PTR(-ENOMEM);
    35	
  > 36		ctx_in = u64_to_user_ptr(kattr->test.ctx_in);
    37		if (copy_from_user(args->args, ctx_in, size_in))
    38			goto out;
    39	
    40		/* args[0] is 0 means state argument of test_N will be NULL */
    41		u_state = u64_to_user_ptr(args->args[0]);
    42		if (u_state && copy_from_user(&args->state, u_state,
    43					      sizeof(args->state)))
    44			goto out;
    45	
    46		return args;
    47	out:
    48		kfree(args);
    49		return ERR_PTR(-EFAULT);
    50	}
    51	

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