Re: [PATCH v0.8 2/6] mm, x86/uaccess: add userspace atomic helpers

From: kernel test robot <lkp@intel.com>
To: Peter Oskolkov <posk@posk.io>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	linux-kernel@vger.kernel.org, linux-api@vger.kernel.org
Cc: llvm@lists.linux.dev, kbuild-all@lists.01.org,
	Linux Memory Management List <linux-mm@kvack.org>,
	Paul Turner <pjt@google.com>
Subject: Re: [PATCH v0.8 2/6] mm, x86/uaccess: add userspace atomic helpers
Date: Fri, 5 Nov 2021 14:10:16 +0800	[thread overview]
Message-ID: <202111051441.KCqxuSZ1-lkp@intel.com> (raw)
In-Reply-To: <20211104195804.83240-3-posk@google.com>

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Hi Peter,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on 8ea9183db4ad8afbcb7089a77c23eaf965b0cacd]

url:    https://github.com/0day-ci/linux/commits/Peter-Oskolkov/sched-mm-x86-uaccess-implement-User-Managed-Concurrency-Groups/20211105-035945
base:   8ea9183db4ad8afbcb7089a77c23eaf965b0cacd
config: arm-randconfig-r026-20211105 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 847a6807332b13f43704327c2d30103ec0347c77)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # https://github.com/0day-ci/linux/commit/23012d2a531975af519f3a7c7a3152197efcbe13
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Peter-Oskolkov/sched-mm-x86-uaccess-implement-User-Managed-Concurrency-Groups/20211105-035945
        git checkout 23012d2a531975af519f3a7c7a3152197efcbe13
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=arm 

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

All warnings (new ones prefixed by >>):

>> mm/maccess.c:491: warning: expecting prototype for xchg_user_[32|64][_nofault|]() - exchange 32/64(). Prototype was for xchg_user_32_nofault() instead

vim +491 mm/maccess.c

   474	
   475	/**
   476	 * xchg_user_[32|64][_nofault|]() - exchange 32/64-bit values
   477	 * @uaddr:   Destination address, in user space;
   478	 * @val:     Source address, in kernel space.
   479	 *
   480	 * This is the standard atomic xchg: exchange values pointed to by @uaddr and @val.
   481	 *
   482	 * The _nofault versions don't fault and can be used in
   483	 * atomic/preempt-disabled contexts.
   484	 *
   485	 * Return:
   486	 * 0      : OK/success;
   487	 * -EINVAL: @uaddr is not properly aligned ('may fault' versions only);
   488	 * -EFAULT: memory access error (including mis-aligned @uaddr in _nofault).
   489	 */
   490	int xchg_user_32_nofault(u32 __user *uaddr, u32 *val)
 > 491	{
   492		int ret;
   493	
   494		if (unlikely(!access_ok(uaddr, sizeof(*uaddr))))
   495			return -EFAULT;
   496	
   497		pagefault_disable();
   498	
   499		if (!user_access_begin(uaddr, sizeof(*uaddr))) {
   500			pagefault_enable();
   501			return -EFAULT;
   502		}
   503	
   504		ret = __try_xchg_user_32(val, uaddr, *val);
   505		user_access_end();
   506	
   507		pagefault_enable();
   508	
   509		return ret;
   510	}
   511	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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