Hello, On Thu, Apr 19, 2018 at 12:06:09PM +0800, Jiang Biao wrote: > The initializing of q->root_blkg is currently outside of queue lock > and rcu, so the blkg may be destroied before the initializing, which > may cause dangling/null references. On the other side, the destroys > of blkg are protected by queue lock or rcu. Put the initializing > inside the queue lock and rcu to make it safer. Hmm... I can't think of a scenario where the above could happen. The queue is still being initialized and no one else has access to it, so I can't see how it could be destroyed. Can you please describe the sequence of events? Have you actually observed this happening? Thanks. -- tejun
