linux-kernel - mm/memcontrol-v1.c:1105:23: sparse: sparse: incompatible types in comparison expression (different address spaces):

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Message-ID: <202505131641.826RQ1yc-lkp@intel.com>
Date: Tue, 13 May 2025 16:16:34 +0800
From: kernel test robot <lkp@...el.com>
To: Roman Gushchin <roman.gushchin@...ux.dev>
Cc: oe-kbuild-all@...ts.linux.dev, linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linux Memory Management List <linux-mm@...ck.org>
Subject: mm/memcontrol-v1.c:1105:23: sparse: sparse: incompatible types in
 comparison expression (different address spaces):

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   e9565e23cd89d4d5cd4388f8742130be1d6f182d
commit: e548ad4a7cbf765f3ab74f6aa1aecc2df390a0b2 mm: memcg: move charge migration code to memcontrol-v1.c
date:   10 months ago
config: m68k-randconfig-r121-20250513 (https://download.01.org/0day-ci/archive/20250513/202505131641.826RQ1yc-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 14.2.0
reproduce: (https://download.01.org/0day-ci/archive/20250513/202505131641.826RQ1yc-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@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202505131641.826RQ1yc-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> mm/memcontrol-v1.c:1105:23: sparse: sparse: incompatible types in comparison expression (different address spaces):
   mm/memcontrol-v1.c:1105:23: sparse:    struct task_struct [noderef] __rcu *
   mm/memcontrol-v1.c:1105:23: sparse:    struct task_struct *
   mm/memcontrol-v1.c:413:6: sparse: sparse: context imbalance in 'folio_memcg_lock' - wrong count at exit
   mm/memcontrol-v1.c: note: in included file (through include/linux/sched.h, include/linux/cgroup.h, include/linux/memcontrol.h):
   include/linux/spinlock.h:406:9: sparse: sparse: context imbalance in '__folio_memcg_unlock' - unexpected unlock
   include/linux/spinlock.h:391:9: sparse: sparse: context imbalance in 'mem_cgroup_count_precharge_pte_range' - unexpected unlock
   include/linux/spinlock.h:391:9: sparse: sparse: context imbalance in 'mem_cgroup_move_charge_pte_range' - unexpected unlock

vim +1105 mm/memcontrol-v1.c

  1058	
  1059	int mem_cgroup_can_attach(struct cgroup_taskset *tset)
  1060	{
  1061		struct cgroup_subsys_state *css;
  1062		struct mem_cgroup *memcg = NULL; /* unneeded init to make gcc happy */
  1063		struct mem_cgroup *from;
  1064		struct task_struct *leader, *p;
  1065		struct mm_struct *mm;
  1066		unsigned long move_flags;
  1067		int ret = 0;
  1068	
  1069		/* charge immigration isn't supported on the default hierarchy */
  1070		if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
  1071			return 0;
  1072	
  1073		/*
  1074		 * Multi-process migrations only happen on the default hierarchy
  1075		 * where charge immigration is not used.  Perform charge
  1076		 * immigration if @tset contains a leader and whine if there are
  1077		 * multiple.
  1078		 */
  1079		p = NULL;
  1080		cgroup_taskset_for_each_leader(leader, css, tset) {
  1081			WARN_ON_ONCE(p);
  1082			p = leader;
  1083			memcg = mem_cgroup_from_css(css);
  1084		}
  1085		if (!p)
  1086			return 0;
  1087	
  1088		/*
  1089		 * We are now committed to this value whatever it is. Changes in this
  1090		 * tunable will only affect upcoming migrations, not the current one.
  1091		 * So we need to save it, and keep it going.
  1092		 */
  1093		move_flags = READ_ONCE(memcg->move_charge_at_immigrate);
  1094		if (!move_flags)
  1095			return 0;
  1096	
  1097		from = mem_cgroup_from_task(p);
  1098	
  1099		VM_BUG_ON(from == memcg);
  1100	
  1101		mm = get_task_mm(p);
  1102		if (!mm)
  1103			return 0;
  1104		/* We move charges only when we move a owner of the mm */
> 1105		if (mm->owner == p) {
  1106			VM_BUG_ON(mc.from);
  1107			VM_BUG_ON(mc.to);
  1108			VM_BUG_ON(mc.precharge);
  1109			VM_BUG_ON(mc.moved_charge);
  1110			VM_BUG_ON(mc.moved_swap);
  1111	
  1112			spin_lock(&mc.lock);
  1113			mc.mm = mm;
  1114			mc.from = from;
  1115			mc.to = memcg;
  1116			mc.flags = move_flags;
  1117			spin_unlock(&mc.lock);
  1118			/* We set mc.moving_task later */
  1119	
  1120			ret = mem_cgroup_precharge_mc(mm);
  1121			if (ret)
  1122				mem_cgroup_clear_mc();
  1123		} else {
  1124			mmput(mm);
  1125		}
  1126		return ret;
  1127	}
  1128	

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