mm/vmscan.c:6585:66: sparse: sparse: Using plain integer as NULL pointer

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   26fd6bff2c050196005312d1d306889220952a99
commit: 874a0a566ede40f3d6062cae8fe1022e616edd1a mm: vmscan: add cgroup IDs to vmscan tracepoints
date:   4 weeks ago
config: m68k-randconfig-r113-20260501 (https://download.01.org/0day-ci/archive/20260501/202605011838.0NbkvDxs-lkp@xxxxxxxxx/config)
compiler: m68k-linux-gcc (GCC) 8.5.0
sparse: v0.6.5-rc1
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260501/202605011838.0NbkvDxs-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Fixes: 874a0a566ede ("mm: vmscan: add cgroup IDs to vmscan tracepoints")
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202605011838.0NbkvDxs-lkp@xxxxxxxxx/

sparse warnings: (new ones prefixed by >>)
>> mm/vmscan.c:6585:66: sparse: sparse: Using plain integer as NULL pointer
   mm/vmscan.c:6589:58: sparse: sparse: Using plain integer as NULL pointer

vim +6585 mm/vmscan.c

  6551	
  6552	unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
  6553					gfp_t gfp_mask, nodemask_t *nodemask)
  6554	{
  6555		unsigned long nr_reclaimed;
  6556		struct scan_control sc = {
  6557			.nr_to_reclaim = SWAP_CLUSTER_MAX,
  6558			.gfp_mask = current_gfp_context(gfp_mask),
  6559			.reclaim_idx = gfp_zone(gfp_mask),
  6560			.order = order,
  6561			.nodemask = nodemask,
  6562			.priority = DEF_PRIORITY,
  6563			.may_writepage = 1,
  6564			.may_unmap = 1,
  6565			.may_swap = 1,
  6566		};
  6567	
  6568		/*
  6569		 * scan_control uses s8 fields for order, priority, and reclaim_idx.
  6570		 * Confirm they are large enough for max values.
  6571		 */
  6572		BUILD_BUG_ON(MAX_PAGE_ORDER >= S8_MAX);
  6573		BUILD_BUG_ON(DEF_PRIORITY > S8_MAX);
  6574		BUILD_BUG_ON(MAX_NR_ZONES > S8_MAX);
  6575	
  6576		/*
  6577		 * Do not enter reclaim if fatal signal was delivered while throttled.
  6578		 * 1 is returned so that the page allocator does not OOM kill at this
  6579		 * point.
  6580		 */
  6581		if (throttle_direct_reclaim(sc.gfp_mask, zonelist, nodemask))
  6582			return 1;
  6583	
  6584		set_task_reclaim_state(current, &sc.reclaim_state);
> 6585		trace_mm_vmscan_direct_reclaim_begin(sc.gfp_mask, order, 0);
  6586	
  6587		nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
  6588	
  6589		trace_mm_vmscan_direct_reclaim_end(nr_reclaimed, 0);
  6590		set_task_reclaim_state(current, NULL);
  6591	
  6592		return nr_reclaimed;
  6593	}
  6594	

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