From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Date: Wed, 25 Aug 2021 18:31:03 +0200
Subject: [PATCH] nbd: add missing locking to the nbd_dev_add error path
Git-commit: 93f63bc41f699318807df202a175d564c26bda87
Patch-mainline: v5.15-rc1
References: jsc#PED-1183
idr_remove needs external synchronization.
Fixes: 6e4df4c64881 ("nbd: reduce the nbd_index_mutex scope")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
[hch: split from a larger patch]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210825163108.50713-2-hch@lst.de
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
drivers/block/nbd.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 379032a64a7c..0c1389da3066 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1770,7 +1770,9 @@ static struct nbd_device *nbd_dev_add(int index, unsigned int refs)
return nbd;
out_free_idr:
+ mutex_lock(&nbd_index_mutex);
idr_remove(&nbd_index_idr, index);
+ mutex_unlock(&nbd_index_mutex);
out_free_tags:
blk_mq_free_tag_set(&nbd->tag_set);
out_free_nbd:
--
2.35.3