Re: [PATCH V5 6/9] blk-mq: always free hctx after request queue is freed

2019-04-13 Thread Ming Lei
On Fri, Apr 12, 2019 at 01:06:07PM +0200, Hannes Reinecke wrote: > On 4/12/19 5:30 AM, Ming Lei wrote: > > In normal queue cleanup path, hctx is released after request queue > > is freed, see blk_mq_release(). > > > > However, in __blk_mq_update_nr_hw_queues(), hctx may be freed because > > of hw

Re: [PATCH V5 6/9] blk-mq: always free hctx after request queue is freed

2019-04-12 Thread Hannes Reinecke
On 4/12/19 5:30 AM, Ming Lei wrote: In normal queue cleanup path, hctx is released after request queue is freed, see blk_mq_release(). However, in __blk_mq_update_nr_hw_queues(), hctx may be freed because of hw queues shrinking. This way is easy to cause use-after-free, because: one implicit rul