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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2010-04-23 21:26:38 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2010-05-04 18:25:03 +0200 |
| commit | ad4ba375373937817404fd92239ef4cadbded23b (patch) | |
| tree | 1c59ebd7a1e3ace3539396dd35ecff0f06132fe8 /mm/memcontrol.c | |
| parent | cgroup: Check task_lock in task_subsys_state() (diff) | |
| download | linux-ad4ba375373937817404fd92239ef4cadbded23b.tar.xz linux-ad4ba375373937817404fd92239ef4cadbded23b.zip | |
memcg: css_id() must be called under rcu_read_lock()
This patch fixes task_in_mem_cgroup(), mem_cgroup_uncharge_swapcache(),
mem_cgroup_move_swap_account(), and is_target_pte_for_mc() to protect
calls to css_id(). An additional RCU lockdep splat was reported for
memcg_oom_wake_function(), however, this function is not yet in
mainline as of 2.6.34-rc5.
Reported-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index f4ede99c8b9b..e06490d4ae5e 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -811,10 +811,12 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) * enabled in "curr" and "curr" is a child of "mem" in *cgroup* * hierarchy(even if use_hierarchy is disabled in "mem"). */ + rcu_read_lock(); if (mem->use_hierarchy) ret = css_is_ancestor(&curr->css, &mem->css); else ret = (curr == mem); + rcu_read_unlock(); css_put(&curr->css); return ret; } @@ -2312,7 +2314,9 @@ mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) /* record memcg information */ if (do_swap_account && swapout && memcg) { + rcu_read_lock(); swap_cgroup_record(ent, css_id(&memcg->css)); + rcu_read_unlock(); mem_cgroup_get(memcg); } if (swapout && memcg) @@ -2369,8 +2373,10 @@ static int mem_cgroup_move_swap_account(swp_entry_t entry, { unsigned short old_id, new_id; + rcu_read_lock(); old_id = css_id(&from->css); new_id = css_id(&to->css); + rcu_read_unlock(); if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { mem_cgroup_swap_statistics(from, false); @@ -4038,11 +4044,16 @@ static int is_target_pte_for_mc(struct vm_area_struct *vma, put_page(page); } /* throught */ - if (ent.val && do_swap_account && !ret && - css_id(&mc.from->css) == lookup_swap_cgroup(ent)) { - ret = MC_TARGET_SWAP; - if (target) - target->ent = ent; + if (ent.val && do_swap_account && !ret) { + unsigned short id; + rcu_read_lock(); + id = css_id(&mc.from->css); + rcu_read_unlock(); + if (id == lookup_swap_cgroup(ent)) { + ret = MC_TARGET_SWAP; + if (target) + target->ent = ent; + } } return ret; } |