[PATCH rcu 12/14] rcuscale: NULL out top-level pointers to heap memory

[neeraj . upadhyay]

From: "Paul E. McKenney" <paul...@kernel.org>

Currently, if someone modprobes and rmmods rcuscale successfully, but
the next run errors out during the modprobe, non-NULL pointers to freed
memory will remain.  If the run after that also errors out during the
modprobe, there will be double-free bugs.

This commit therefore NULLs out top-level pointers to memory that has
just been freed.

Signed-off-by: "Paul E. McKenney" <paul...@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadh...@kernel.org>
---
 kernel/rcu/rcuscale.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c
index bc7cca979c06..61a178914256 100644
--- a/kernel/rcu/rcuscale.c
+++ b/kernel/rcu/rcuscale.c
@@ -819,6 +819,7 @@ kfree_scale_cleanup(void)
                        torture_stop_kthread(kfree_scale_thread,
                                             kfree_reader_tasks[i]);
                kfree(kfree_reader_tasks);
+               kfree_reader_tasks = NULL;
        }
 
        torture_cleanup_end();
@@ -987,6 +988,7 @@ rcu_scale_cleanup(void)
                        torture_stop_kthread(rcu_scale_reader,
                                             reader_tasks[i]);
                kfree(reader_tasks);
+               reader_tasks = NULL;
        }
 
        if (writer_tasks) {
@@ -1043,8 +1045,11 @@ rcu_scale_cleanup(void)
                        }
                }
                kfree(writer_tasks);
+               writer_tasks = NULL;
                kfree(writer_durations);
+               writer_durations = NULL;
                kfree(writer_n_durations);
+               writer_n_durations = NULL;
                kfree(writer_done);
                writer_done = NULL;
                kfree(writer_freelists);
-- 
2.40.1