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From:   Yu Kuai <yukuai1@huaweicloud.com>
To:     hch@lst.de, axboe@kernel.dk, agk@redhat.com, snitzer@kernel.org,
        dm-devel@redhat.com
Cc:     linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        yukuai3@huawei.com, yukuai1@huaweicloud.com, yi.zhang@huawei.com
Subject: [PATCH v3 01/10] block: clear ->slave_dir when dropping the main slave_dir reference
Date:   Tue, 15 Nov 2022 22:10:45 +0800
Message-Id: <20221115141054.1051801-2-yukuai1@huaweicloud.com>
In-Reply-To: <20221115141054.1051801-1-yukuai1@huaweicloud.com>
References: <20221115141054.1051801-1-yukuai1@huaweicloud.com>
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From: Christoph Hellwig <hch@lst.de>

Zero out the pointer to ->slave_dir so that the holder code doesn't
incorrectly treat the object as alive when add_disk failed or after
del_gendisk was called.

Fixes: 89f871af1b26 ("dm: delay registering the gendisk")
Reported-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
 block/genhd.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/block/genhd.c b/block/genhd.c
index 74026ce31405..e9501c66ba4d 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -530,6 +530,7 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
 	rq_qos_exit(disk->queue);
 out_put_slave_dir:
 	kobject_put(disk->slave_dir);
+	disk->slave_dir = NULL;
 out_put_holder_dir:
 	kobject_put(disk->part0->bd_holder_dir);
 out_del_integrity:
@@ -634,6 +635,7 @@ void del_gendisk(struct gendisk *disk)
 
 	kobject_put(disk->part0->bd_holder_dir);
 	kobject_put(disk->slave_dir);
+	disk->slave_dir = NULL;
 
 	part_stat_set_all(disk->part0, 0);
 	disk->part0->bd_stamp = 0;
-- 
2.31.1