Merge tag 'regmap-fix-v4.8-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git...

[cascardo/linux.git] / mm / mempolicy.c

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index d8c4e38..2da72a5 100644 (file)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2336,6 +2336,23 @@ out:
        return ret;
 }
 
+/*
+ * Drop the (possibly final) reference to task->mempolicy.  It needs to be
+ * dropped after task->mempolicy is set to NULL so that any allocation done as
+ * part of its kmem_cache_free(), such as by KASAN, doesn't reference a freed
+ * policy.
+ */
+void mpol_put_task_policy(struct task_struct *task)
+{
+       struct mempolicy *pol;
+
+       task_lock(task);
+       pol = task->mempolicy;
+       task->mempolicy = NULL;
+       task_unlock(task);
+       mpol_put(pol);
+}
+
 static void sp_delete(struct shared_policy *sp, struct sp_node *n)
 {
        pr_debug("deleting %lx-l%lx\n", n->start, n->end);