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-rw-r--r--kernel/sched/core.c14
1 files changed, 7 insertions, 7 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 59ce0841eb1f..35a35e36024b 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4466,12 +4466,7 @@ int task_call_func(struct task_struct *p, task_call_f func, void *arg)
* @cpu: The CPU on which to snapshot the task.
*
* Returns the task_struct pointer of the task "currently" running on
- * the specified CPU. If the same task is running on that CPU throughout,
- * the return value will be a pointer to that task's task_struct structure.
- * If the CPU did any context switches even vaguely concurrently with the
- * execution of this function, the return value will be a pointer to the
- * task_struct structure of a randomly chosen task that was running on
- * that CPU somewhere around the time that this function was executing.
+ * the specified CPU.
*
* If the specified CPU was offline, the return value is whatever it
* is, perhaps a pointer to the task_struct structure of that CPU's idle
@@ -4485,11 +4480,16 @@ int task_call_func(struct task_struct *p, task_call_f func, void *arg)
*/
struct task_struct *cpu_curr_snapshot(int cpu)
{
+ struct rq *rq = cpu_rq(cpu);
struct task_struct *t;
+ struct rq_flags rf;
- smp_mb(); /* Pairing determined by caller's synchronization design. */
+ rq_lock_irqsave(rq, &rf);
+ smp_mb__after_spinlock(); /* Pairing determined by caller's synchronization design. */
t = rcu_dereference(cpu_curr(cpu));
+ rq_unlock_irqrestore(rq, &rf);
smp_mb(); /* Pairing determined by caller's synchronization design. */
+
return t;
}