Merge git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc-merge

[powerpc.git] / kernel / futex.c

diff --git a/kernel/futex.c b/kernel/futex.c
index 5872e35..5efa2f9 100644 (file)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -270,7 +270,13 @@ static void wake_futex(struct futex_q *q)
        /*
         * The waiting task can free the futex_q as soon as this is written,
         * without taking any locks.  This must come last.
+        *
+        * A memory barrier is required here to prevent the following store
+        * to lock_ptr from getting ahead of the wakeup. Clearing the lock
+        * at the end of wake_up_all() does not prevent this store from
+        * moving.
         */
+       wmb();
        q->lock_ptr = NULL;
 }
 
@@ -350,6 +356,13 @@ retry:
                if (bh1 != bh2)
                        spin_unlock(&bh2->lock);
 
+#ifndef CONFIG_MMU
+               /* we don't get EFAULT from MMU faults if we don't have an MMU,
+                * but we might get them from range checking */
+               ret = op_ret;
+               goto out;
+#endif
+
                if (unlikely(op_ret != -EFAULT)) {
                        ret = op_ret;
                        goto out;