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

Pull scheduler fixes from Ingo Molnar:
 "Three small fixes"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/clock: Prevent tracing recursion in sched_clock_cpu()
  stop_machine: Fix^2 race between stop_two_cpus() and stop_cpus()
  sched/deadline: Deny unprivileged users to set/change SCHED_DEADLINE policy

3 files changed, 12 insertions, 3 deletions

diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c
index 43c2bcc35761..b30a2924ef14 100644
--- a/kernel/sched/clock.c
+++ b/kernel/sched/clock.c
@@ -301,14 +301,14 @@ u64 sched_clock_cpu(int cpu)
         if (unlikely(!sched_clock_running))
                 return 0ull;
 
-        preempt_disable();
+        preempt_disable_notrace();
         scd = cpu_sdc(cpu);
 
         if (cpu != smp_processor_id())
                 clock = sched_clock_remote(scd);
         else
                 clock = sched_clock_local(scd);
-        preempt_enable();
+        preempt_enable_notrace();
 
         return clock;
 }
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 6edbef296ece..f5c6635b806c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3338,6 +3338,15 @@ recheck:
                                 return -EPERM;
                 }
 
+                 /*
+                  * Can't set/change SCHED_DEADLINE policy at all for now
+                  * (safest behavior); in the future we would like to allow
+                  * unprivileged DL tasks to increase their relative deadline
+                  * or reduce their runtime (both ways reducing utilization)
+                  */
+                if (dl_policy(policy))
+                        return -EPERM;
+
                 /*
                  * Treat SCHED_IDLE as nice 20. Only allow a switch to
                  * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 84571e09c907..01fbae5b97b7 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -293,7 +293,7 @@ int stop_two_cpus(unsigned int cpu1, unsigned int cpu2, cpu_stop_fn_t fn, void *
          */
         smp_call_function_single(min(cpu1, cpu2),
                                  &irq_cpu_stop_queue_work,
-                                 &call_args, 0);
+                                 &call_args, 1);
         lg_local_unlock(&stop_cpus_lock);
         preempt_enable();