Merge branch 'stable-3.2' into pandora-3.2

[pandora-kernel.git] / kernel / sched.c

diff --git a/kernel/sched.c b/kernel/sched.c
index fe33d0f..f4235a7 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1016,8 +1016,10 @@ static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
         * After ->on_cpu is cleared, the task can be moved to a different CPU.
         * We must ensure this doesn't happen until the switch is completely
         * finished.
+        *
+        * Pairs with the control dependency and rmb in try_to_wake_up().
         */
-       smp_wmb();
+       smp_mb();
        prev->on_cpu = 0;
 #endif
 #ifdef CONFIG_DEBUG_SPINLOCK
@@ -2930,7 +2932,6 @@ out:
  */
 int wake_up_process(struct task_struct *p)
 {
-       WARN_ON(task_is_stopped_or_traced(p));
        return try_to_wake_up(p, TASK_NORMAL, 0);
 }
 EXPORT_SYMBOL(wake_up_process);
@@ -3191,11 +3192,11 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
         * If a task dies, then it sets TASK_DEAD in tsk->state and calls
         * schedule one last time. The schedule call will never return, and
         * the scheduled task must drop that reference.
-        * The test for TASK_DEAD must occur while the runqueue locks are
-        * still held, otherwise prev could be scheduled on another cpu, die
-        * there before we look at prev->state, and then the reference would
-        * be dropped twice.
-        *              Manfred Spraul <manfred@colorfullife.com>
+        *
+        * We must observe prev->state before clearing prev->on_cpu (in
+        * finish_lock_switch), otherwise a concurrent wakeup can get prev
+        * running on another CPU and we could rave with its RUNNING -> DEAD
+        * transition, resulting in a double drop.
         */
        prev_state = prev->state;
        finish_arch_switch(prev);
@@ -5303,6 +5304,7 @@ int can_nice(const struct task_struct *p, const int nice)
        return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
                capable(CAP_SYS_NICE));
 }
+EXPORT_SYMBOL_GPL(can_nice);
 
 #ifdef __ARCH_WANT_SYS_NICE
 
@@ -7169,11 +7171,11 @@ static int init_rootdomain(struct root_domain *rd)
 {
        memset(rd, 0, sizeof(*rd));
 
-       if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
+       if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL))
                goto out;
-       if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
+       if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL))
                goto free_span;
-       if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
+       if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
                goto free_online;
 
        if (cpupri_init(&rd->cpupri) != 0)