[openeuler:openEuler-1.0-LTS 1421/1421] include/linux/thread_info.h:59:17: warning: 'ctl' may be used uninitialized

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

Hi Jens,

FYI, the error/warning was bisected to this commit, please ignore it if it's irrelevant.

tree:   https://gitee.com/openeuler/kernel.git openEuler-1.0-LTS
head:   cc7cb040bd0afe96f1da94c9f21eda5a986510a5
commit: c6e864fee7c3dd416048d129997c7def53cb9ed8 [1421/1421] net: separate out the msghdr copy from ___sys_{send,recv}msg()
config: x86_64-buildonly-randconfig-002-20250208 (https://download.01.org/0day-ci/archive/20250208/202502082355.jrzYRRaD-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250208/202502082355.jrzYRRaD-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/202502082355.jrzYRRaD-lkp@intel.com/

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   In function '__sock_release',
       inlined from 'sock_close' at net/socket.c:1140:2:
   net/socket.c:579:21: warning: array subscript -1 is outside array bounds of 'struct inode[9078122083518480]' [-Warray-bounds]
     579 |                 sock->ops->release(sock);
         |                 ~~~~^~~~~
   net/socket.c:580:26: warning: array subscript -1 is outside array bounds of 'struct inode[9078122083518480]' [-Warray-bounds]
     580 |                 sock->sk = NULL;
   In file included from arch/x86/include/asm/preempt.h:7,
                    from include/linux/preempt.h:81,
                    from include/linux/spinlock.h:51,
                    from include/linux/mmzone.h:9,
                    from include/linux/gfp.h:6,
                    from include/linux/mm.h:11,
                    from net/socket.c:61:
   In function 'check_object_size',
       inlined from 'check_copy_size' at include/linux/thread_info.h:90:2,
       inlined from 'copy_from_user' at include/linux/uaccess.h:143:6,
       inlined from '____sys_sendmsg' at net/socket.c:2110:7:
>> include/linux/thread_info.h:59:17: warning: 'ctl' may be used uninitialized [-Wmaybe-uninitialized]
      59 |                 __check_object_size(ptr, n, to_user);
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/thread_info.h: In function '____sys_sendmsg':
   include/linux/thread_info.h:52:13: note: by argument 1 of type 'const void *' to '__check_object_size' declared here
      52 | extern void __check_object_size(const void *ptr, unsigned long n,
         |             ^~~~~~~~~~~~~~~~~~~
   net/socket.c:2075:23: note: 'ctl' declared here
    2075 |         unsigned char ctl[sizeof(struct cmsghdr) + 20]
         |                       ^~~
   In function 'check_object_size',
       inlined from 'check_copy_size' at include/linux/thread_info.h:90:2,
       inlined from 'copy_from_user' at include/linux/uaccess.h:143:6,
       inlined from '__do_sys_socketcall' at net/socket.c:2618:6,
       inlined from '__se_sys_socketcall' at net/socket.c:2602:1:
   include/linux/thread_info.h:59:17: warning: 'a' may be used uninitialized [-Wmaybe-uninitialized]
      59 |                 __check_object_size(ptr, n, to_user);
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/thread_info.h: In function '__se_sys_socketcall':
   include/linux/thread_info.h:52:13: note: by argument 1 of type 'const void *' to '__check_object_size' declared here
      52 | extern void __check_object_size(const void *ptr, unsigned long n,
         |             ^~~~~~~~~~~~~~~~~~~
   net/socket.c:2604:23: note: 'a' declared here
    2604 |         unsigned long a[AUDITSC_ARGS];
         |                       ^
   net/socket.c:573: warning: Function parameter or member 'inode' not described in '__sock_release'


vim +/ctl +59 include/linux/thread_info.h

0f60a8efe4005a Kees Cook 2016-07-12  50  
f5509cc18daa7f Kees Cook 2016-06-07  51  #ifdef CONFIG_HARDENED_USERCOPY
f5509cc18daa7f Kees Cook 2016-06-07  52  extern void __check_object_size(const void *ptr, unsigned long n,
f5509cc18daa7f Kees Cook 2016-06-07  53  					bool to_user);
f5509cc18daa7f Kees Cook 2016-06-07  54  
a85d6b8242dc78 Kees Cook 2016-09-07  55  static __always_inline void check_object_size(const void *ptr, unsigned long n,
f5509cc18daa7f Kees Cook 2016-06-07  56  					      bool to_user)
f5509cc18daa7f Kees Cook 2016-06-07  57  {
81409e9e280588 Kees Cook 2016-08-31  58  	if (!__builtin_constant_p(n))
f5509cc18daa7f Kees Cook 2016-06-07 @59  		__check_object_size(ptr, n, to_user);
f5509cc18daa7f Kees Cook 2016-06-07  60  }
f5509cc18daa7f Kees Cook 2016-06-07  61  #else
f5509cc18daa7f Kees Cook 2016-06-07  62  static inline void check_object_size(const void *ptr, unsigned long n,
f5509cc18daa7f Kees Cook 2016-06-07  63  				     bool to_user)
f5509cc18daa7f Kees Cook 2016-06-07  64  { }
f5509cc18daa7f Kees Cook 2016-06-07  65  #endif /* CONFIG_HARDENED_USERCOPY */
f5509cc18daa7f Kees Cook 2016-06-07  66  

:::::: The code at line 59 was first introduced by commit
:::::: f5509cc18daa7f82bcc553be70df2117c8eedc16 mm: Hardened usercopy

:::::: TO: Kees Cook <keescook@chromium.org>
:::::: CC: Kees Cook <keescook@chromium.org>

-- 
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https://github.com/intel/lkp-tests/wiki