diff options
| -rw-r--r-- | block/blk-mq.c | 7 | ||||
| -rw-r--r-- | include/linux/blk-mq.h | 13 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 2 |
3 files changed, 19 insertions, 3 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index 1ef81110eb8a..4e96bb246247 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -4535,7 +4535,12 @@ static void __blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set, if (hctxs) memcpy(new_hctxs, hctxs, q->nr_hw_queues * sizeof(*hctxs)); - q->queue_hw_ctx = new_hctxs; + rcu_assign_pointer(q->queue_hw_ctx, new_hctxs); + /* + * Make sure reading the old queue_hw_ctx from other + * context concurrently won't trigger uaf. + */ + synchronize_rcu_expedited(); kfree(hctxs); hctxs = new_hctxs; } diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 9208ff90ae16..eb7254b3dddd 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -1015,9 +1015,20 @@ static inline void *blk_mq_rq_to_pdu(struct request *rq) return rq + 1; } +static inline struct blk_mq_hw_ctx *queue_hctx(struct request_queue *q, int id) +{ + struct blk_mq_hw_ctx *hctx; + + rcu_read_lock(); + hctx = rcu_dereference(q->queue_hw_ctx)[id]; + rcu_read_unlock(); + + return hctx; +} + #define queue_for_each_hw_ctx(q, hctx, i) \ for ((i) = 0; (i) < (q)->nr_hw_queues && \ - ({ hctx = (q)->queue_hw_ctx[i]; 1; }); (i)++) + ({ hctx = queue_hctx((q), i); 1; }); (i)++) #define hctx_for_each_ctx(hctx, ctx, i) \ for ((i) = 0; (i) < (hctx)->nr_ctx && \ diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 6195f89648db..72e34acd439c 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -503,7 +503,7 @@ struct request_queue { /* hw dispatch queues */ unsigned int nr_hw_queues; - struct blk_mq_hw_ctx **queue_hw_ctx; + struct blk_mq_hw_ctx * __rcu *queue_hw_ctx; struct percpu_ref q_usage_counter; struct lock_class_key io_lock_cls_key; |