[rgushchin:memcontrol_v1.rfc 4/10] mm/memcontrol-v1.c:1109:23: sparse: sparse: incompatible types in comparison expression (different address spaces):

[kernel test robot <lkp@intel.com>]

tree:   https://github.com/rgushchin/linux.git memcontrol_v1.rfc
head:   0011ac60f32b91542b15b122087bd97f41634b51
commit: bb7dddcd85b885a163916d548d1907c89771fd67 [4/10] mm: memcg: move charge migration code to memcontrol-v1.c
config: i386-randconfig-061-20240510 (https://download.01.org/0day-ci/archive/20240510/202405100515.D644UVCg-lkp@intel.com/config)
compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240510/202405100515.D644UVCg-lkp@intel.com/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
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202405100515.D644UVCg-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> mm/memcontrol-v1.c:1109:23: sparse: sparse: incompatible types in comparison expression (different address spaces):
   mm/memcontrol-v1.c:1109:23: sparse:    struct task_struct [noderef] __rcu *
   mm/memcontrol-v1.c:1109:23: sparse:    struct task_struct *
   mm/memcontrol-v1.c:417:6: sparse: sparse: context imbalance in 'folio_memcg_lock' - wrong count at exit
   mm/memcontrol-v1.c:464:17: sparse: sparse: context imbalance in '__folio_memcg_unlock' - unexpected unlock
   mm/memcontrol-v1.c: note: in included file (through include/linux/rculist.h, include/linux/cgroup.h, include/linux/memcontrol.h):
   include/linux/rcupdate.h:812:9: sparse: sparse: context imbalance in 'mem_cgroup_count_precharge_pte_range' - unexpected unlock
   include/linux/rcupdate.h:812:9: sparse: sparse: context imbalance in 'mem_cgroup_move_charge_pte_range' - unexpected unlock

vim +1109 mm/memcontrol-v1.c

  1062	
  1063	int mem_cgroup_can_attach(struct cgroup_taskset *tset)
  1064	{
  1065		struct cgroup_subsys_state *css;
  1066		struct mem_cgroup *memcg = NULL; /* unneeded init to make gcc happy */
  1067		struct mem_cgroup *from;
  1068		struct task_struct *leader, *p;
  1069		struct mm_struct *mm;
  1070		unsigned long move_flags;
  1071		int ret = 0;
  1072	
  1073		/* charge immigration isn't supported on the default hierarchy */
  1074		if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
  1075			return 0;
  1076	
  1077		/*
  1078		 * Multi-process migrations only happen on the default hierarchy
  1079		 * where charge immigration is not used.  Perform charge
  1080		 * immigration if @tset contains a leader and whine if there are
  1081		 * multiple.
  1082		 */
  1083		p = NULL;
  1084		cgroup_taskset_for_each_leader(leader, css, tset) {
  1085			WARN_ON_ONCE(p);
  1086			p = leader;
  1087			memcg = mem_cgroup_from_css(css);
  1088		}
  1089		if (!p)
  1090			return 0;
  1091	
  1092		/*
  1093		 * We are now committed to this value whatever it is. Changes in this
  1094		 * tunable will only affect upcoming migrations, not the current one.
  1095		 * So we need to save it, and keep it going.
  1096		 */
  1097		move_flags = READ_ONCE(memcg->move_charge_at_immigrate);
  1098		if (!move_flags)
  1099			return 0;
  1100	
  1101		from = mem_cgroup_from_task(p);
  1102	
  1103		VM_BUG_ON(from == memcg);
  1104	
  1105		mm = get_task_mm(p);
  1106		if (!mm)
  1107			return 0;
  1108		/* We move charges only when we move a owner of the mm */
> 1109		if (mm->owner == p) {
  1110			VM_BUG_ON(mc.from);
  1111			VM_BUG_ON(mc.to);
  1112			VM_BUG_ON(mc.precharge);
  1113			VM_BUG_ON(mc.moved_charge);
  1114			VM_BUG_ON(mc.moved_swap);
  1115	
  1116			spin_lock(&mc.lock);
  1117			mc.mm = mm;
  1118			mc.from = from;
  1119			mc.to = memcg;
  1120			mc.flags = move_flags;
  1121			spin_unlock(&mc.lock);
  1122			/* We set mc.moving_task later */
  1123	
  1124			ret = mem_cgroup_precharge_mc(mm);
  1125			if (ret)
  1126				mem_cgroup_clear_mc();
  1127		} else {
  1128			mmput(mm);
  1129		}
  1130		return ret;
  1131	}
  1132	

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