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Commit c3b4afca authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

blk-mq: free hctx->ctxs in queue's release handler 



Now blk_cleanup_queue() can be called before calling
del_gendisk()[1], inside which hctx->ctxs is touched
from blk_mq_unregister_hctx(), but the variable has
been freed by blk_cleanup_queue() at that time.

So this patch moves freeing of hctx->ctxs into queue's
release handler for fixing the oops reported by Stefan.

[1], 6cd18e71 (block: destroy bdi before blockdev is
unregistered)

Reported-by: default avatarStefan Seyfried <stefan.seyfried@googlemail.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org (v4.0)
Signed-off-by: default avatarMing Lei <tom.leiming@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent d4a4f75c

block/blk-mq.c

+6 −2
Original line number Diff line number Diff line
@@ -1600,6 +1600,7 @@ static int blk_mq_hctx_notify(void *data, unsigned long action, 
	return NOTIFY_OK;

}



/* hctx->ctxs will be freed in queue's release handler */

static void blk_mq_exit_hctx(struct request_queue *q,

		struct blk_mq_tag_set *set,

		struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
@@ -1618,7 +1619,6 @@ static void blk_mq_exit_hctx(struct request_queue *q, 


	blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier);

	blk_free_flush_queue(hctx->fq);

	kfree(hctx->ctxs);

	blk_mq_free_bitmap(&hctx->ctx_map);

}
@@ -1891,8 +1891,12 @@ void blk_mq_release(struct request_queue *q) 
	unsigned int i;



	/* hctx kobj stays in hctx */

	queue_for_each_hw_ctx(q, hctx, i)

	queue_for_each_hw_ctx(q, hctx, i) {

		if (!hctx)

			continue;

		kfree(hctx->ctxs);

		kfree(hctx);

	}



	kfree(q->queue_hw_ctx);