Merge branch 'linus' into tracing-v28-for-linus-v3

Conflicts:
	init/main.c
	kernel/module.c
	scripts/bootgraph.pl

1 files changed, 4 insertions, 5 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 7b71f87f1207..138887881a11 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -644,24 +644,23 @@ retry:
 assign_new_owner:
 	BUG_ON(c == p);
 	get_task_struct(c);
+	read_unlock(&tasklist_lock);
+	down_write(&mm->mmap_sem);
 	/*
 	 * The task_lock protects c->mm from changing.
 	 * We always want mm->owner->mm == mm
 	 */
 	task_lock(c);
-	/*
-	 * Delay read_unlock() till we have the task_lock()
-	 * to ensure that c does not slip away underneath us
-	 */
-	read_unlock(&tasklist_lock);
 	if (c->mm != mm) {
 		task_unlock(c);
+		up_write(&mm->mmap_sem);
 		put_task_struct(c);
 		goto retry;
 	}
 	cgroup_mm_owner_callbacks(mm->owner, c);
 	mm->owner = c;
 	task_unlock(c);
+	up_write(&mm->mmap_sem);
 	put_task_struct(c);
 }
 #endif /* CONFIG_MM_OWNER */