A single argument can be invoked only from a sleepable
context. There is already a might_sleep() check to mitigate
such cases. The problem is that it requires a kernel to
be built with a CONFIG_DEBUG_ATOMIC_SLEEP option.
In order to improve an extra runtime_assert_can_sleep()
function is introduced by this patch. It is a run-time
checking. Please note it only covers PREEMPT kernels.
Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
---
kernel/rcu/tree.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index d155f2594317..bb798f07e768 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3232,6 +3232,19 @@ add_ptr_to_bulk_krc_lock(struct kfree_rcu_cpu **krcp,
return true;
}
+static void
+runtime_assert_can_sleep(void)
+{
+ if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
+ return;
+
+ if (preemptible())
+ return;
+
+ WARN_ONCE(1, "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
+ in_atomic(), irqs_disabled(), current->pid, current->comm);
+}
+
/*
* Queue a request for lazy invocation of the appropriate free routine
* after a grace period. Please note that three paths are maintained,
@@ -3257,8 +3270,10 @@ void kvfree_call_rcu(struct rcu_head *head, void *ptr)
* only. For other places please embed an rcu_head to
* your data.
*/
- if (!head)
+ if (!head) {
+ runtime_assert_can_sleep();
might_sleep();
+ }
// Queue the object but don't yet schedule the batch.
if (debug_rcu_head_queue(ptr)) {
--
2.30.2
