Triiger a warning if a grace period is not passed yet for
objects queued on a linked list via rcu_head structures.
Once detached, take a full snapsot of GP sequnces to check
later that a grace period is passed and it is safe to free
all pointers.
Based on latest 'dev' branch.
Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
---
kernel/rcu/tree.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 4838a55da34f..35be35f8236b 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2802,6 +2802,7 @@ struct kvfree_rcu_bulk_data {
struct kfree_rcu_cpu_work {
struct rcu_work rcu_work;
struct rcu_head *head_free;
+ struct rcu_gp_oldstate head_free_gp_snap;
struct list_head bulk_head_free[FREE_N_CHANNELS];
struct kfree_rcu_cpu *krcp;
};
@@ -3007,6 +3008,7 @@ static void kfree_rcu_work(struct work_struct *work)
struct rcu_head *head;
struct kfree_rcu_cpu *krcp;
struct kfree_rcu_cpu_work *krwp;
+ struct rcu_gp_oldstate head_gp_snap;
int i;
krwp = container_of(to_rcu_work(work),
@@ -3021,6 +3023,7 @@ static void kfree_rcu_work(struct work_struct *work)
// Channel 3.
head = krwp->head_free;
krwp->head_free = NULL;
+ head_gp_snap = krwp->head_free_gp_snap;
raw_spin_unlock_irqrestore(&krcp->lock, flags);
// Handle the first two channels.
@@ -3037,7 +3040,8 @@ static void kfree_rcu_work(struct work_struct *work)
* queued on a linked list through their rcu_head structures.
* This list is named "Channel 3".
*/
- kvfree_rcu_list(head);
+ if (head && !WARN_ON_ONCE(!poll_state_synchronize_rcu_full(&head_gp_snap)))
+ kvfree_rcu_list(head);
}
static bool
@@ -3169,6 +3173,7 @@ static void kfree_rcu_monitor(struct work_struct *work)
// objects queued on the linked list.
if (!krwp->head_free) {
krwp->head_free = krcp->head;
+ get_state_synchronize_rcu_full(&krwp->head_free_gp_snap);
atomic_set(&krcp->head_count, 0);
WRITE_ONCE(krcp->head, NULL);
}
--
2.30.2
