linux-kernel - [tip:locking/core 19/44] kernel/futex/syscalls.c:82:16: sparse: sparse: cast removes address space '_

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Date:   Fri, 29 Oct 2021 03:51:11 +0800
From:   kernel test robot <lkp@...el.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     kbuild-all@...ts.01.org, linux-kernel@...r.kernel.org,
        x86@...nel.org,
        André Almeida <andrealmeid@...labora.com>
Subject: [tip:locking/core 19/44] kernel/futex/syscalls.c:82:16: sparse:
 sparse: cast removes address space '__user' of expression

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking/core
head:   5197fcd09ab6dcc4df79edec7e8e27575276374c
commit: af8cc9600bbf2251b04c56139f7c83f87c3f878a [19/44] futex: Split out syscalls
config: riscv-randconfig-s031-20211028 (attached as .config)
compiler: riscv32-linux-gcc (GCC) 11.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-dirty
        # https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=af8cc9600bbf2251b04c56139f7c83f87c3f878a
        git remote add tip https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
        git fetch --no-tags tip locking/core
        git checkout af8cc9600bbf2251b04c56139f7c83f87c3f878a
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=riscv SHELL=/bin/bash kernel/futex/

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


sparse warnings: (new ones prefixed by >>)
>> kernel/futex/syscalls.c:82:16: sparse: sparse: cast removes address space '__user' of expression

vim +/__user +82 kernel/futex/syscalls.c

    44	
    45	/**
    46	 * sys_get_robust_list() - Get the robust-futex list head of a task
    47	 * @pid:	pid of the process [zero for current task]
    48	 * @head_ptr:	pointer to a list-head pointer, the kernel fills it in
    49	 * @len_ptr:	pointer to a length field, the kernel fills in the header size
    50	 */
    51	SYSCALL_DEFINE3(get_robust_list, int, pid,
    52			struct robust_list_head __user * __user *, head_ptr,
    53			size_t __user *, len_ptr)
    54	{
    55		struct robust_list_head __user *head;
    56		unsigned long ret;
    57		struct task_struct *p;
    58	
    59		if (!futex_cmpxchg_enabled)
    60			return -ENOSYS;
    61	
    62		rcu_read_lock();
    63	
    64		ret = -ESRCH;
    65		if (!pid)
    66			p = current;
    67		else {
    68			p = find_task_by_vpid(pid);
    69			if (!p)
    70				goto err_unlock;
    71		}
    72	
    73		ret = -EPERM;
    74		if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
    75			goto err_unlock;
    76	
    77		head = p->robust_list;
    78		rcu_read_unlock();
    79	
    80		if (put_user(sizeof(*head), len_ptr))
    81			return -EFAULT;
  > 82		return put_user(head, head_ptr);
    83	
    84	err_unlock:
    85		rcu_read_unlock();
    86	
    87		return ret;
    88	}
    89	

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

Download attachment ".config.gz" of type "application/gzip" (32302 bytes)