3 files changed, 32 insertions, 4 deletions

diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c
index c685e31492df..c3ae1446461c 100644
--- a/kernel/sched/clock.c
+++ b/kernel/sched/clock.c
@@ -176,10 +176,36 @@ static u64 sched_clock_remote(struct sched_clock_data *scd)
         u64 this_clock, remote_clock;
         u64 *ptr, old_val, val;
 
+#if BITS_PER_LONG != 64
+again:
+        /*
+         * Careful here: The local and the remote clock values need to
+         * be read out atomic as we need to compare the values and
+         * then update either the local or the remote side. So the
+         * cmpxchg64 below only protects one readout.
+         *
+         * We must reread via sched_clock_local() in the retry case on
+         * 32bit as an NMI could use sched_clock_local() via the
+         * tracer and hit between the readout of
+         * the low32bit and the high 32bit portion.
+         */
+        this_clock = sched_clock_local(my_scd);
+        /*
+         * We must enforce atomic readout on 32bit, otherwise the
+         * update on the remote cpu can hit inbetween the readout of
+         * the low32bit and the high 32bit portion.
+         */
+        remote_clock = cmpxchg64(&scd->clock, 0, 0);
+#else
+        /*
+         * On 64bit the read of [my]scd->clock is atomic versus the
+         * update, so we can avoid the above 32bit dance.
+         */
         sched_clock_local(my_scd);
 again:
         this_clock = my_scd->clock;
         remote_clock = scd->clock;
+#endif
 
         /*
          * Use the opportunity that we have both locks
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7f12624a393c..67d04651f44b 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1498,8 +1498,10 @@ static void try_to_wake_up_local(struct task_struct *p)
 {
         struct rq *rq = task_rq(p);
 
-        BUG_ON(rq != this_rq());
-        BUG_ON(p == current);
+        if (WARN_ON_ONCE(rq != this_rq()) ||
+            WARN_ON_ONCE(p == current))
+                return;
+
         lockdep_assert_held(&rq->lock);
 
         if (!raw_spin_trylock(&p->pi_lock)) {
@@ -4999,7 +5001,7 @@ static void sd_free_ctl_entry(struct ctl_table **tablep)
 }
 
 static int min_load_idx = 0;
-static int max_load_idx = CPU_LOAD_IDX_MAX;
+static int max_load_idx = CPU_LOAD_IDX_MAX-1;
 
 static void
 set_table_entry(struct ctl_table *entry,
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index ed12cbb135f4..e93cca92f38b 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -310,7 +310,7 @@ void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
 
         t = tsk;
         do {
-                task_cputime(tsk, &utime, &stime);
+                task_cputime(t, &utime, &stime);
                 times->utime += utime;
                 times->stime += stime;
                 times->sum_exec_runtime += task_sched_runtime(t);