Re: [PATCH v2 2/2] linux/bits.h: Add compile time sanity check of GENMASK inputs

From: kbuild test robot <lkp@intel.com>
To: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Cc: kbuild-all@01.org, rikard.falkeborn@gmail.com,
	akpm@linux-foundation.org, joe@perches.com,
	johannes@sipsolutions.net, linux-kernel@vger.kernel.org,
	yamada.masahiro@socionext.com
Subject: Re: [PATCH v2 2/2] linux/bits.h: Add compile time sanity check of GENMASK inputs
Date: Thu, 8 Aug 2019 10:44:27 +0800	[thread overview]
Message-ID: <201908081055.B87mXkwi%lkp@intel.com> (raw)
In-Reply-To: <20190801230358.4193-2-rikard.falkeborn@gmail.com>

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Hi Rikard,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[cannot apply to v5.3-rc3 next-20190807]
[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/Rikard-Falkeborn/linux-bits-h-Clarify-macro-argument-names/20190805-024030
config: i386-defconfig (attached as .config)
compiler: gcc-7 (Debian 7.4.0-10) 7.4.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   In file included from include/linux/bits.h:22:0,
                    from arch/x86/include/asm/msr-index.h:5,
                    from arch/x86/boot/cpucheck.c:28:
>> include/linux/build_bug.h:49:0: warning: "BUILD_BUG_ON" redefined
    #define BUILD_BUG_ON(condition) \

   In file included from arch/x86/boot/cpucheck.c:22:0:
   arch/x86/boot/boot.h:31:0: note: this is the location of the previous definition
    #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))

vim +/BUILD_BUG_ON +49 include/linux/build_bug.h

bc6245e5efd70c Ian Abbott 2017-07-10  40  
bc6245e5efd70c Ian Abbott 2017-07-10  41  /**
bc6245e5efd70c Ian Abbott 2017-07-10  42   * BUILD_BUG_ON - break compile if a condition is true.
bc6245e5efd70c Ian Abbott 2017-07-10  43   * @condition: the condition which the compiler should know is false.
bc6245e5efd70c Ian Abbott 2017-07-10  44   *
bc6245e5efd70c Ian Abbott 2017-07-10  45   * If you have some code which relies on certain constants being equal, or
bc6245e5efd70c Ian Abbott 2017-07-10  46   * some other compile-time-evaluated condition, you should use BUILD_BUG_ON to
bc6245e5efd70c Ian Abbott 2017-07-10  47   * detect if someone changes it.
bc6245e5efd70c Ian Abbott 2017-07-10  48   */
bc6245e5efd70c Ian Abbott 2017-07-10 @49  #define BUILD_BUG_ON(condition) \
bc6245e5efd70c Ian Abbott 2017-07-10  50  	BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
bc6245e5efd70c Ian Abbott 2017-07-10  51  

:::::: The code at line 49 was first introduced by commit
:::::: bc6245e5efd70c41eaf9334b1b5e646745cb0fb3 bug: split BUILD_BUG stuff out into <linux/build_bug.h>

:::::: TO: Ian Abbott <abbotti@mev.co.uk>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>

---
0-DAY kernel test infrastructure                Open Source Technology Center
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