Messages in this thread Patch in this message | | | From | Akinobu Mita <> | Subject | [PATCH 2/4] blk-mq: fix q->mq_map access race | Date | Sun, 21 Jun 2015 22:52:29 +0900 |
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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 and set to NULL 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 deleting the queue from all_q_list earlier than destroyng q->mq_map.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Jens Axboe <axboe@kernel.dk> --- block/blk-mq.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c index ec94258..6487710 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2038,6 +2038,10 @@ void blk_mq_free_queue(struct request_queue *q) { struct blk_mq_tag_set *set = q->tag_set; + mutex_lock(&all_q_mutex); + list_del_init(&q->all_q_node); + mutex_unlock(&all_q_mutex); + blk_mq_del_queue_tag_set(q); blk_mq_exit_hw_queues(q, set, set->nr_hw_queues); @@ -2048,10 +2052,6 @@ void blk_mq_free_queue(struct request_queue *q) 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); } /* Basically redo blk_mq_init_queue with queue frozen */ -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/
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