The patch titled
cpuset: rcu_read_lock() to protect task_cs()
has been removed from the -mm tree. Its filename was
cpuset-rcu_read_lock-to-protect-task_cs.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: cpuset: rcu_read_lock() to protect task_cs()
From: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
task_cs() calls task_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
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