1 files changed, 21 insertions, 7 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 9bb7489ee645..0dc3158667a2 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2906,6 +2906,7 @@ static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
  * @q: the waitqueue
  * @mode: which threads
  * @nr_exclusive: how many wake-one or wake-many threads to wake up
+ * @key: is directly passed to the wakeup function
  */
 void fastcall __wake_up(wait_queue_head_t *q, unsigned int mode,
                                 int nr_exclusive, void *key)
@@ -2928,7 +2929,7 @@ void fastcall __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
 }
 
 /**
- * __wake_up - sync- wake up threads blocked on a waitqueue.
+ * __wake_up_sync - wake up threads blocked on a waitqueue.
  * @q: the waitqueue
  * @mode: which threads
  * @nr_exclusive: how many wake-one or wake-many threads to wake up
@@ -3223,6 +3224,19 @@ out_unlock:
 
 EXPORT_SYMBOL(set_user_nice);
 
+/*
+ * can_nice - check if a task can reduce its nice value
+ * @p: task
+ * @nice: nice value
+ */
+int can_nice(const task_t *p, const int nice)
+{
+        /* convert nice value [19,-20] to rlimit style value [0,39] */
+        int nice_rlim = 19 - nice;
+        return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur ||
+                capable(CAP_SYS_NICE));
+}
+
 #ifdef __ARCH_WANT_SYS_NICE
 
 /*
@@ -3242,12 +3256,8 @@ asmlinkage long sys_nice(int increment)
          * We don't have to worry. Conceptually one call occurs first
          * and we have a single winner.
          */
-        if (increment < 0) {
-                if (!capable(CAP_SYS_NICE))
-                        return -EPERM;
-                if (increment < -40)
-                        increment = -40;
-        }
+        if (increment < -40)
+                increment = -40;
         if (increment > 40)
                 increment = 40;
 
@@ -3257,6 +3267,9 @@ asmlinkage long sys_nice(int increment)
         if (nice > 19)
                 nice = 19;
 
+        if (increment < 0 && !can_nice(current, nice))
+                return -EPERM;
+
         retval = security_task_setnice(current, nice);
         if (retval)
                 return retval;
@@ -3372,6 +3385,7 @@ recheck:
                 return -EINVAL;
 
         if ((policy == SCHED_FIFO || policy == SCHED_RR) &&
+            param->sched_priority > p->signal->rlim[RLIMIT_RTPRIO].rlim_cur &&
             !capable(CAP_SYS_NICE))
                 return -EPERM;
         if ((current->euid != p->euid) && (current->euid != p->uid) &&