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From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
To: axboe@kernel.dk, damien.lemoal@wdc.com,
	johannes.thumshirn@edc.com, martin.petersen@oracle.com
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Subject: [PATCH] drivers/block/null_blk/main: Fix a double free in null_init.
Date: Mon, 26 Apr 2021 07:32:29 -0700	[thread overview]
Message-ID: <20210426143229.7374-1-lyl2019@mail.ustc.edu.cn> (raw)

In null_init, null_add_dev(dev) is called.
In null_add_dev, it calls null_free_zoned_dev(dev) to free dev->zones
via kvfree(dev->zones) in out_cleanup_zone branch and returns err.
Then null_init accept the err code and then calls null_free_dev(dev).

But in null_free_dev(dev), dev->zones is freed again by
null_free_zoned_dev().

My patch set dev->zones to NULL in null_free_zoned_dev() after
kvfree(dev->zones) is called, to avoid the double free.

Fixes: 2984c8684f962 ("nullb: factor disk parameters")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
---
 drivers/block/null_blk/zoned.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/block/null_blk/zoned.c b/drivers/block/null_blk/zoned.c
index bfcab1c782b5..dae54dd1aeac 100644
--- a/drivers/block/null_blk/zoned.c
+++ b/drivers/block/null_blk/zoned.c
@@ -180,6 +180,7 @@ int null_register_zoned_dev(struct nullb *nullb)
 void null_free_zoned_dev(struct nullb_device *dev)
 {
 	kvfree(dev->zones);
+	dev->zones = NULL;
 }
 
 int null_report_zones(struct gendisk *disk, sector_t sector,
-- 
2.25.1



             reply	other threads:[~2021-04-26 14:32 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-26 14:32 Lv Yunlong [this message]
2021-04-26 15:05 ` [PATCH] drivers/block/null_blk/main: Fix a double free in null_init Jens Axboe

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