[PATCH 5.11 388/601] drivers/block/null_blk/main: Fix a double free in null_init.

Greg Kroah-Hartman
2021-05-12T17:41:43Z

From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>

[ Upstream commit 72ce11ddfa4e9e1879103581a60b7e34547eaa0a ]

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>
Link: https://lore.kernel.org/r/20210426143229.7374-1-lyl2019@mail.ustc.edu.cn
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 fce0a54df0e5..8e0656964f1c 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,
--
2.30.2