Re: [PATCH v8 2/3] cachestat: implement cachestat syscall

[kernel test robot]

Hi Nhat,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on 1440f576022887004f719883acb094e7e0dd4944]

url:    https://github.com/intel-lab-lkp/linux/commits/Nhat-Pham/workingset-refactor-LRU-refault-to-expose-refault-recency-check/20230128-171134
base:   1440f576022887004f719883acb094e7e0dd4944
patch link:    https://lore.kernel.org/r/20230126175356.1582123-3-nphamcs%40gmail.com
patch subject: [PATCH v8 2/3] cachestat: implement cachestat syscall
config: s390-randconfig-s051-20230129 (https://download.01.org/0day-ci/archive/20230129/202301292044.JVAnbg9W-lkp@xxxxxxxxx/config)
compiler: s390-linux-gcc (GCC) 12.1.0
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: v0.6.4-39-gce1a6720-dirty
        # https://github.com/intel-lab-lkp/linux/commit/a05ffdcecfe9ac147066fb8472e6fb75491d0eed
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Nhat-Pham/workingset-refactor-LRU-refault-to-expose-refault-recency-check/20230128-171134
        git checkout a05ffdcecfe9ac147066fb8472e6fb75491d0eed
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=s390 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=s390 SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@xxxxxxxxx>

sparse warnings: (new ones prefixed by >>)
>> mm/filemap.c:4075:1: sparse: sparse: Using plain integer as NULL pointer
>> mm/filemap.c:4075:1: sparse: sparse: Using plain integer as NULL pointer
   mm/filemap.c:1416:17: sparse: sparse: context imbalance in 'migration_entry_wait_on_locked' - unexpected unlock

vim +4075 mm/filemap.c

  4037	
  4038	#ifdef CONFIG_CACHESTAT_SYSCALL
  4039	/*
  4040	 * The cachestat(5) system call.
  4041	 *
  4042	 * cachestat() returns the page cache statistics of a file in the
  4043	 * bytes range specified by `off` and `len`: number of cached pages,
  4044	 * number of dirty pages, number of pages marked for writeback,
  4045	 * number of evicted pages, and number of recently evicted pages.
  4046	 *
  4047	 * An evicted page is a page that is previously in the page cache
  4048	 * but has been evicted since. A page is recently evicted if its last
  4049	 * eviction was recent enough that its reentry to the cache would
  4050	 * indicate that it is actively being used by the system, and that
  4051	 * there is memory pressure on the system.
  4052	 *
  4053	 * `off` and `len` must be non-negative integers. If `len` > 0,
  4054	 * the queried range is [`off`, `off` + `len`]. If `len` == 0,
  4055	 * we will query in the range from `off` to the end of the file.
  4056	 *
  4057	 * `cstat_version` is an unsigned integer indicating the specific version
  4058	 * of the cachestat struct. It must be at least 1, and does not exceed the
  4059	 * latest version number (which is currently 1). For now, user should
  4060	 * just pass 1.
  4061	 *
  4062	 * The `flags` argument is unused for now, but is included for future
  4063	 * extensibility. User should pass 0 (i.e no flag specified).
  4064	 *
  4065	 * Because the status of a page can change after cachestat() checks it
  4066	 * but before it returns to the application, the returned values may
  4067	 * contain stale information.
  4068	 *
  4069	 * return values:
  4070	 *  zero    - success
  4071	 *  -EFAULT - cstat points to an illegal address
  4072	 *  -EINVAL - invalid arguments
  4073	 *  -EBADF	- invalid file descriptor
  4074	 */
> 4075	SYSCALL_DEFINE6(cachestat, unsigned int, fd, off_t, off, size_t, len,

-- 
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