1 files changed, 29 insertions, 22 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 1e4a600a6163..054ff47c4478 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -47,19 +47,21 @@ static DEFINE_SPINLOCK(zone_scan_lock);
 #ifdef CONFIG_NUMA
 /**
  * has_intersects_mems_allowed() - check task eligiblity for kill
- * @tsk: task struct of which task to consider
+ * @start: task struct of which task to consider
  * @mask: nodemask passed to page allocator for mempolicy ooms
  *
  * Task eligibility is determined by whether or not a candidate task, @tsk,
  * shares the same mempolicy nodes as current if it is bound by such a policy
  * and whether or not it has the same set of allowed cpuset nodes.
  */
-static bool has_intersects_mems_allowed(struct task_struct *tsk,
+static bool has_intersects_mems_allowed(struct task_struct *start,
                                         const nodemask_t *mask)
 {
-        struct task_struct *start = tsk;
+        struct task_struct *tsk;
+        bool ret = false;
 
-        do {
+        rcu_read_lock();
+        for_each_thread(start, tsk) {
                 if (mask) {
                         /*
                          * If this is a mempolicy constrained oom, tsk's
@@ -67,19 +69,20 @@ static bool has_intersects_mems_allowed(struct task_struct *tsk,
                          * mempolicy intersects current, otherwise it may be
                          * needlessly killed.
                          */
-                        if (mempolicy_nodemask_intersects(tsk, mask))
-                                return true;
+                        ret = mempolicy_nodemask_intersects(tsk, mask);
                 } else {
                         /*
                          * This is not a mempolicy constrained oom, so only
                          * check the mems of tsk's cpuset.
                          */
-                        if (cpuset_mems_allowed_intersects(current, tsk))
-                                return true;
+                        ret = cpuset_mems_allowed_intersects(current, tsk);
                 }
-        } while_each_thread(start, tsk);
+                if (ret)
+                        break;
+        }
+        rcu_read_unlock();
 
-        return false;
+        return ret;
 }
 #else
 static bool has_intersects_mems_allowed(struct task_struct *tsk,
@@ -97,16 +100,21 @@ static bool has_intersects_mems_allowed(struct task_struct *tsk,
  */
 struct task_struct *find_lock_task_mm(struct task_struct *p)
 {
-        struct task_struct *t = p;
+        struct task_struct *t;
 
-        do {
+        rcu_read_lock();
+
+        for_each_thread(p, t) {
                 task_lock(t);
                 if (likely(t->mm))
-                        return t;
+                        goto found;
                 task_unlock(t);
-        } while_each_thread(p, t);
+        }
+        t = NULL;
+found:
+        rcu_read_unlock();
 
-        return NULL;
+        return t;
 }
 
 /* return true if the task is not adequate as candidate victim task. */
@@ -301,7 +309,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
         unsigned long chosen_points = 0;
 
         rcu_read_lock();
-        do_each_thread(g, p) {
+        for_each_process_thread(g, p) {
                 unsigned int points;
 
                 switch (oom_scan_process_thread(p, totalpages, nodemask,
@@ -323,7 +331,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
                         chosen = p;
                         chosen_points = points;
                 }
-        } while_each_thread(g, p);
+        }
         if (chosen)
                 get_task_struct(chosen);
         rcu_read_unlock();
@@ -406,7 +414,7 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
 {
         struct task_struct *victim = p;
         struct task_struct *child;
-        struct task_struct *t = p;
+        struct task_struct *t;
         struct mm_struct *mm;
         unsigned int victim_points = 0;
         static DEFINE_RATELIMIT_STATE(oom_rs, DEFAULT_RATELIMIT_INTERVAL,
@@ -437,7 +445,7 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
          * still freeing memory.
          */
         read_lock(&tasklist_lock);
-        do {
+        for_each_thread(p, t) {
                 list_for_each_entry(child, &t->children, sibling) {
                         unsigned int child_points;
 
@@ -455,13 +463,11 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
                                 get_task_struct(victim);
                         }
                 }
-        } while_each_thread(p, t);
+        }
         read_unlock(&tasklist_lock);
 
-        rcu_read_lock();
         p = find_lock_task_mm(victim);
         if (!p) {
-                rcu_read_unlock();
                 put_task_struct(victim);
                 return;
         } else if (victim != p) {
@@ -487,6 +493,7 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
          * That thread will now get access to memory reserves since it has a
          * pending fatal signal.
          */
+        rcu_read_lock();
         for_each_process(p)
                 if (p->mm == mm && !same_thread_group(p, victim) &&
                     !(p->flags & PF_KTHREAD)) {