On 03/19, David Howells wrote:
--- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -218,8 +218,10 @@ static void key_garbage_collector(struct work_struct *work) key = rb_entry(cursor, struct key, serial_node); cursor = rb_next(cursor);
if (refcount_read(&key->usage) == 0)
if (test_bit(KEY_FLAG_FINAL_PUT, &key->flags)) {smp_mb(); /* Clobber key->user after FINAL_PUT seen. */ goto found_unreferenced_key;}if (unlikely(gc_state & KEY_GC_REAPING_DEAD_1)) { if (key->type == key_gc_dead_keytype) { diff --git a/security/keys/key.c b/security/keys/key.c index 3d7d185019d3..7198cd2ac3a3 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -658,6 +658,8 @@ void key_put(struct key *key) key->user->qnbytes -= key->quotalen; spin_unlock_irqrestore(&key->user->lock, flags); }
smp_mb(); /* key->user before FINAL_PUT set. */
Can't resist, smp_mb__before_atomic() should equally work, but this doesn't really matter, please forget.
set_bit(KEY_FLAG_FINAL_PUT, &key->flags); schedule_work(&key_gc_work);
I believe this patch is correct,
Reviewed-by: Oleg Nesterov oleg@redhat.com