On Thu, Jul 2, 2015 at 10:29 PM, Akinobu Mita <[email protected]> wrote: > CPU hotplug handling for blk-mq (blk_mq_queue_reinit) updates > q->mq_map by blk_mq_update_queue_map() for all request queues in > all_q_list. On the other hand, q->mq_map is released before deleting > the queue from all_q_list. > > So if CPU hotplug event occurs in the window, invalid memory access > can happen. Fix it by releasing q->mq_map in blk_mq_release() to make > it happen latter than removal from all_q_list. > > Signed-off-by: Akinobu Mita <[email protected]> > Suggested-by: Ming Lei <[email protected]> > Cc: Jens Axboe <[email protected]> > Cc: Ming Lei <[email protected]>
Reviewed-by: Ming Lei <[email protected]> > --- > block/blk-mq.c | 8 +++----- > 1 file changed, 3 insertions(+), 5 deletions(-) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index f537796..c5da908 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -1928,6 +1928,9 @@ void blk_mq_release(struct request_queue *q) > kfree(hctx); > } > > + kfree(q->mq_map); > + q->mq_map = NULL; > + > kfree(q->queue_hw_ctx); > > /* ctx kobj stays in queue_ctx */ > @@ -2073,11 +2076,6 @@ void blk_mq_free_queue(struct request_queue *q) > blk_mq_free_hw_queues(q, set); > > percpu_ref_exit(&q->mq_usage_counter); > - > - kfree(q->mq_map); > - > - q->mq_map = NULL; > - > mutex_lock(&all_q_mutex); > list_del_init(&q->all_q_node); > mutex_unlock(&all_q_mutex); > -- > 1.9.1 > -- Ming Lei -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
