[PATCH] rcu_torture_lock deadlock fix
rcu_torture_lock is used in a softirq-unsafe manner, but it is also
taken by rcu_torture_cb(), which may execute in softirq-context,
resulting in potential deadlocks.
The fix is to acquire rcu_torture_lock in a softirq-safe manner. With
this fix applied, the rcu-torture code passes validation.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Paul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 7732199..7712912 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -114,16 +114,16 @@
{
struct list_head *p;
- spin_lock(&rcu_torture_lock);
+ spin_lock_bh(&rcu_torture_lock);
if (list_empty(&rcu_torture_freelist)) {
atomic_inc(&n_rcu_torture_alloc_fail);
- spin_unlock(&rcu_torture_lock);
+ spin_unlock_bh(&rcu_torture_lock);
return NULL;
}
atomic_inc(&n_rcu_torture_alloc);
p = rcu_torture_freelist.next;
list_del_init(p);
- spin_unlock(&rcu_torture_lock);
+ spin_unlock_bh(&rcu_torture_lock);
return container_of(p, struct rcu_torture, rtort_free);
}
@@ -134,9 +134,9 @@
rcu_torture_free(struct rcu_torture *p)
{
atomic_inc(&n_rcu_torture_free);
- spin_lock(&rcu_torture_lock);
+ spin_lock_bh(&rcu_torture_lock);
list_add_tail(&p->rtort_free, &rcu_torture_freelist);
- spin_unlock(&rcu_torture_lock);
+ spin_unlock_bh(&rcu_torture_lock);
}
static void