Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Ingo Molnar:
 "Various fixlets, mostly related to the (root-only) SCHED_DEADLINE
  policy, but also a hotplug bug fix and a fix for a NR_CPUS related
  overallocation bug causing a suspend/resume regression"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Fix hotplug vs. set_cpus_allowed_ptr()
  sched/cpupri: Replace NR_CPUS arrays
  sched/deadline: Replace NR_CPUS arrays
  sched/deadline: Restrict user params max value to 2^63 ns
  sched/deadline: Change sched_getparam() behaviour vs SCHED_DEADLINE
  sched: Disallow sched_attr::sched_policy < 0
  sched: Make sched_setattr() correctly return -EFBIG

1 files changed, 39 insertions, 16 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 204d3d281809..0a7251678982 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3195,17 +3195,40 @@ __getparam_dl(struct task_struct *p, struct sched_attr *attr)
  * We ask for the deadline not being zero, and greater or equal
  * than the runtime, as well as the period of being zero or
  * greater than deadline. Furthermore, we have to be sure that
- * user parameters are above the internal resolution (1us); we
- * check sched_runtime only since it is always the smaller one.
+ * user parameters are above the internal resolution of 1us (we
+ * check sched_runtime only since it is always the smaller one) and
+ * below 2^63 ns (we have to check both sched_deadline and
+ * sched_period, as the latter can be zero).
  */
 static bool
 __checkparam_dl(const struct sched_attr *attr)
 {
-        return attr && attr->sched_deadline != 0 &&
-                (attr->sched_period == 0 ||
-                (s64)(attr->sched_period   - attr->sched_deadline) >= 0) &&
-                (s64)(attr->sched_deadline - attr->sched_runtime ) >= 0  &&
-                attr->sched_runtime >= (2 << (DL_SCALE - 1));
+        /* deadline != 0 */
+        if (attr->sched_deadline == 0)
+                return false;
+
+        /*
+         * Since we truncate DL_SCALE bits, make sure we're at least
+         * that big.
+         */
+        if (attr->sched_runtime < (1ULL << DL_SCALE))
+                return false;
+
+        /*
+         * Since we use the MSB for wrap-around and sign issues, make
+         * sure it's not set (mind that period can be equal to zero).
+         */
+        if (attr->sched_deadline & (1ULL << 63) ||
+            attr->sched_period & (1ULL << 63))
+                return false;
+
+        /* runtime <= deadline <= period (if period != 0) */
+        if ((attr->sched_period != 0 &&
+             attr->sched_period < attr->sched_deadline) ||
+            attr->sched_deadline < attr->sched_runtime)
+                return false;
+
+        return true;
 }
 
 /*
@@ -3658,8 +3681,12 @@ SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr,
         if (!uattr || pid < 0 || flags)
                 return -EINVAL;
 
-        if (sched_copy_attr(uattr, &attr))
-                return -EFAULT;
+        retval = sched_copy_attr(uattr, &attr);
+        if (retval)
+                return retval;
+
+        if (attr.sched_policy < 0)
+                return -EINVAL;
 
         rcu_read_lock();
         retval = -ESRCH;
@@ -3709,7 +3736,7 @@ SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
  */
 SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
 {
-        struct sched_param lp;
+        struct sched_param lp = { .sched_priority = 0 };
         struct task_struct *p;
         int retval;
 
@@ -3726,11 +3753,8 @@ SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
         if (retval)
                 goto out_unlock;
 
-        if (task_has_dl_policy(p)) {
-                retval = -EINVAL;
-                goto out_unlock;
-        }
-        lp.sched_priority = p->rt_priority;
+        if (task_has_rt_policy(p))
+                lp.sched_priority = p->rt_priority;
         rcu_read_unlock();
 
         /*
@@ -5052,7 +5076,6 @@ static int sched_cpu_active(struct notifier_block *nfb,
                                       unsigned long action, void *hcpu)
 {
         switch (action & ~CPU_TASKS_FROZEN) {
-        case CPU_STARTING:
         case CPU_DOWN_FAILED:
                 set_cpu_active((long)hcpu, true);
                 return NOTIFY_OK;