Re: [PATCH v9 2/4] seccomp: switch system call argument type to void *

From: kbuild test robot <lkp@intel.com>
To: Tycho Andersen <tycho@tycho.ws>
Cc: kbuild-all@01.org, Kees Cook <keescook@chromium.org>,
	Andy Lutomirski <luto@amacapital.net>,
	Oleg Nesterov <oleg@redhat.com>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	"Serge E . Hallyn" <serge@hallyn.com>,
	Christian Brauner <christian@brauner.io>,
	Tyler Hicks <tyhicks@canonical.com>,
	Akihiro Suda <suda.akihiro@lab.ntt.co.jp>,
	Aleksa Sarai <asarai@suse.de>, Jann Horn <jannh@google.com>,
	linux-kernel@vger.kernel.org,
	containers@lists.linux-foundation.org, linux-api@vger.kernel.org,
	Tycho Andersen <tycho@tycho.ws>
Subject: Re: [PATCH v9 2/4] seccomp: switch system call argument type to void *
Date: Tue, 4 Dec 2018 10:07:38 +0800	[thread overview]
Message-ID: <201812041031.7kJxvTuh%fengguang.wu@intel.com> (raw)
In-Reply-To: <20181203032827.27978-3-tycho@tycho.ws>

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Hi Tycho,

I love your patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.20-rc5 next-20181203]
[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/Tycho-Andersen/seccomp-hoist-struct-seccomp_data-recalculation-higher/20181204-013450
config: i386-randconfig-x005-201848 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

   In file included from kernel/seccomp.c:28:0:
>> include/linux/syscalls.h:239:18: error: conflicting types for 'sys_seccomp'
     asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \
                     ^
   include/linux/syscalls.h:225:2: note: in expansion of macro '__SYSCALL_DEFINEx'
     __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
     ^~~~~~~~~~~~~~~~~
   include/linux/syscalls.h:216:36: note: in expansion of macro 'SYSCALL_DEFINEx'
    #define SYSCALL_DEFINE3(name, ...) SYSCALL_DEFINEx(3, _##name, __VA_ARGS__)
                                       ^~~~~~~~~~~~~~~
   kernel/seccomp.c:946:1: note: in expansion of macro 'SYSCALL_DEFINE3'
    SYSCALL_DEFINE3(seccomp, unsigned int, op, unsigned int, flags,
    ^~~~~~~~~~~~~~~
   In file included from kernel/seccomp.c:28:0:
   include/linux/syscalls.h:881:17: note: previous declaration of 'sys_seccomp' was here
    asmlinkage long sys_seccomp(unsigned int op, unsigned int flags,
                    ^~~~~~~~~~~

vim +/sys_seccomp +239 include/linux/syscalls.h

1bd21c6c2 Dominik Brodowski   2018-04-05  228  
e145242ea Dominik Brodowski   2018-04-09  229  /*
e145242ea Dominik Brodowski   2018-04-09  230   * The asmlinkage stub is aliased to a function named __se_sys_*() which
e145242ea Dominik Brodowski   2018-04-09  231   * sign-extends 32-bit ints to longs whenever needed. The actual work is
e145242ea Dominik Brodowski   2018-04-09  232   * done within __do_sys_*().
e145242ea Dominik Brodowski   2018-04-09  233   */
1bd21c6c2 Dominik Brodowski   2018-04-05  234  #ifndef __SYSCALL_DEFINEx
bed1ffca0 Frederic Weisbecker 2009-03-13  235  #define __SYSCALL_DEFINEx(x, name, ...)					\
bee200317 Arnd Bergmann       2018-06-19  236  	__diag_push();							\
bee200317 Arnd Bergmann       2018-06-19  237  	__diag_ignore(GCC, 8, "-Wattribute-alias",			\
bee200317 Arnd Bergmann       2018-06-19  238  		      "Type aliasing is used to sanitize syscall arguments");\
83460ec8d Andi Kleen          2013-11-12 @239  	asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))	\
e145242ea Dominik Brodowski   2018-04-09  240  		__attribute__((alias(__stringify(__se_sys##name))));	\
c9a211951 Howard McLauchlan   2018-03-21  241  	ALLOW_ERROR_INJECTION(sys##name, ERRNO);			\
e145242ea Dominik Brodowski   2018-04-09  242  	static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\
e145242ea Dominik Brodowski   2018-04-09  243  	asmlinkage long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__));	\
e145242ea Dominik Brodowski   2018-04-09  244  	asmlinkage long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__))	\
1a94bc347 Heiko Carstens      2009-01-14  245  	{								\
e145242ea Dominik Brodowski   2018-04-09  246  		long ret = __do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__));\
07fe6e00f Al Viro             2013-01-21  247  		__MAP(x,__SC_TEST,__VA_ARGS__);				\
2cf096668 Al Viro             2013-01-21  248  		__PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__));	\
2cf096668 Al Viro             2013-01-21  249  		return ret;						\
1a94bc347 Heiko Carstens      2009-01-14  250  	}								\
bee200317 Arnd Bergmann       2018-06-19  251  	__diag_pop();							\
e145242ea Dominik Brodowski   2018-04-09  252  	static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
1bd21c6c2 Dominik Brodowski   2018-04-05  253  #endif /* __SYSCALL_DEFINEx */
1a94bc347 Heiko Carstens      2009-01-14  254  

:::::: The code at line 239 was first introduced by commit
:::::: 83460ec8dcac14142e7860a01fa59c267ac4657c syscalls.h: use gcc alias instead of assembler aliases for syscalls

:::::: TO: Andi Kleen <ak@linux.intel.com>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>

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