The patch titled
cpuset: rcu_read_lock() to protect task_cs()
has been added to the -mm tree. Its filename is
cpuset-rcu_read_lock-to-protect-task_cs.patch
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------------------------------------------------------
Subject: cpuset: rcu_read_lock() to protect task_cs()
From: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
task_cs() calls cgroup_subsys_state().
Ee must use rcu_read_lock() to protect cgroup_subsys_state().
It's correct that top_cpuset is never freed, but cgroup_subsys_state()
accesses css_set, this css_set maybe freed when task_cs() called.
We use use rcu_read_lock() to protect it.
Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
Acked-by: Paul Menage <menage@xxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/cpuset.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)
diff -puN kernel/cpuset.c~cpuset-rcu_read_lock-to-protect-task_cs kernel/cpuset.c
--- a/kernel/cpuset.c~cpuset-rcu_read_lock-to-protect-task_cs
+++ a/kernel/cpuset.c
@@ -375,14 +375,9 @@ void cpuset_update_task_memory_state(voi
struct task_struct *tsk = current;
struct cpuset *cs;
- if (task_cs(tsk) == &top_cpuset) {
- /* Don't need rcu for top_cpuset. It's never freed. */
- my_cpusets_mem_gen = top_cpuset.mems_generation;
- } else {
- rcu_read_lock();
- my_cpusets_mem_gen = task_cs(tsk)->mems_generation;
- rcu_read_unlock();
- }
+ rcu_read_lock();
+ my_cpusets_mem_gen = task_cs(tsk)->mems_generation;
+ rcu_read_unlock();
if (my_cpusets_mem_gen != tsk->cpuset_mems_generation) {
mutex_lock(&callback_mutex);
_
Patches currently in -mm which might be from laijs@xxxxxxxxxxxxxx are
origin.patch
linux-next.patch
kprobes-bugfix-try_module_get-even-if-calling_mod-is-null.patch
cgroups-add-lock-for-child-cgroups-in-cgroup_post_fork.patch
cgroups-fix-cgroup_iter_next-bug.patch
cgroups-dont-put-struct-cgroupfs_root-protected-by-rcu.patch
cgroups-use-task_lock-for-access-tsk-cgroups-safe-in-cgroup_clone.patch
cgroups-call-find_css_set-safely-in-cgroup_attach_task.patch
devcgroup-use-list_for_each_entry_rcu.patch
memcontrol-rcu_read_lock-to-protect-mm_match_cgroup.patch
cpuset-rcu_read_lock-to-protect-task_cs.patch
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