Re: [PATCH 8/8] waitid(): switch copyout of siginfo to unsafe_put_user()

[kbuild test robot]

Hi Al,

[auto build test WARNING on linus/master]
[also build test WARNING on v4.12-rc1 next-20170515]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Al-Viro/move-compat-wait4-and-waitid-next-to-native-variants/20170516-084127
config: arm64-defconfig (attached as .config)
compiler: aarch64-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=arm64 

All warnings (new ones prefixed by >>):

   In file included from include/asm-generic/bug.h:4:0,
                    from arch/arm64/include/asm/bug.h:66,
                    from include/linux/bug.h:4,
                    from include/linux/mmdebug.h:4,
                    from include/linux/mm.h:8,
                    from kernel/exit.c:7:
   kernel/exit.c: In function 'C_SYSC_waitid':
   kernel/exit.c:1746:38: error: 'infop' undeclared (first use in this function)
     unsafe_put_user(err ? 0 : SIGCHLD, &infop->si_signo, Efault);
                                         ^
   include/linux/compiler.h:179:42: note: in definition of macro 'unlikely'
    # define unlikely(x) __builtin_expect(!!(x), 0)
                                             ^
>> arch/arm64/include/asm/uaccess.h:313:2: note: in expansion of macro '__put_user_err'
     __put_user_err((x), (ptr), __pu_err);    \
     ^~~~~~~~~~~~~~
   include/linux/uaccess.h:302:56: note: in expansion of macro '__put_user'
    #define unsafe_put_user(x, ptr, err) do { if (unlikely(__put_user(x, ptr))) goto err; } while (0)
                                                           ^~~~~~~~~~
   kernel/exit.c:1746:2: note: in expansion of macro 'unsafe_put_user'
     unsafe_put_user(err ? 0 : SIGCHLD, &infop->si_signo, Efault);
     ^~~~~~~~~~~~~~~
   kernel/exit.c:1746:38: note: each undeclared identifier is reported only once for each function it appears in
     unsafe_put_user(err ? 0 : SIGCHLD, &infop->si_signo, Efault);
                                         ^
   include/linux/compiler.h:179:42: note: in definition of macro 'unlikely'
    # define unlikely(x) __builtin_expect(!!(x), 0)
                                             ^
>> arch/arm64/include/asm/uaccess.h:313:2: note: in expansion of macro '__put_user_err'
     __put_user_err((x), (ptr), __pu_err);    \
     ^~~~~~~~~~~~~~
   include/linux/uaccess.h:302:56: note: in expansion of macro '__put_user'
    #define unsafe_put_user(x, ptr, err) do { if (unlikely(__put_user(x, ptr))) goto err; } while (0)
                                                           ^~~~~~~~~~
   kernel/exit.c:1746:2: note: in expansion of macro 'unsafe_put_user'
     unsafe_put_user(err ? 0 : SIGCHLD, &infop->si_signo, Efault);
     ^~~~~~~~~~~~~~~

vim +/__put_user_err +313 arch/arm64/include/asm/uaccess.h

57f4959b James Morse     2016-02-05  297  		__put_user_asm("str", "sttr", "%w", __pu_val, (ptr),	\
57f4959b James Morse     2016-02-05  298  			       (err), ARM64_HAS_UAO);			\
0aea86a2 Catalin Marinas 2012-03-05  299  		break;							\
0aea86a2 Catalin Marinas 2012-03-05  300  	case 8:								\
d135b8b5 Mark Rutland    2017-05-03  301  		__put_user_asm("str", "sttr", "%x", __pu_val, (ptr),	\
57f4959b James Morse     2016-02-05  302  			       (err), ARM64_HAS_UAO);			\
0aea86a2 Catalin Marinas 2012-03-05  303  		break;							\
0aea86a2 Catalin Marinas 2012-03-05  304  	default:							\
0aea86a2 Catalin Marinas 2012-03-05  305  		BUILD_BUG();						\
0aea86a2 Catalin Marinas 2012-03-05  306  	}								\
bd38967d Catalin Marinas 2016-07-01  307  	uaccess_disable_not_uao();					\
0aea86a2 Catalin Marinas 2012-03-05  308  } while (0)
0aea86a2 Catalin Marinas 2012-03-05  309  
0aea86a2 Catalin Marinas 2012-03-05  310  #define __put_user(x, ptr)						\
0aea86a2 Catalin Marinas 2012-03-05  311  ({									\
0aea86a2 Catalin Marinas 2012-03-05  312  	int __pu_err = 0;						\
0aea86a2 Catalin Marinas 2012-03-05 @313  	__put_user_err((x), (ptr), __pu_err);				\
0aea86a2 Catalin Marinas 2012-03-05  314  	__pu_err;							\
0aea86a2 Catalin Marinas 2012-03-05  315  })
0aea86a2 Catalin Marinas 2012-03-05  316  
0aea86a2 Catalin Marinas 2012-03-05  317  #define __put_user_error(x, ptr, err)					\
0aea86a2 Catalin Marinas 2012-03-05  318  ({									\
0aea86a2 Catalin Marinas 2012-03-05  319  	__put_user_err((x), (ptr), (err));				\
0aea86a2 Catalin Marinas 2012-03-05  320  	(void)0;							\
0aea86a2 Catalin Marinas 2012-03-05  321  })

:::::: The code at line 313 was first introduced by commit
:::::: 0aea86a2176c22647a5b683768f858d880d5e05b arm64: User access library functions

:::::: TO: Catalin Marinas <catalin.marinas@xxxxxxx>
:::::: CC: Catalin Marinas <catalin.marinas@xxxxxxx>

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0-DAY kernel test infrastructure                Open Source Technology Center
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