From: Lv Yunlong <lyl2019@mail.ustc.edu.cn> stable inclusion from linux-4.19.191 commit 7585643856ae82e1ed105b261d4e57b384648a69 -------------------------------- [ 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> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- 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 1a74871f1bfdd..f64e9122824b4 100644 --- a/drivers/block/null_blk_zoned.c +++ b/drivers/block/null_blk_zoned.c @@ -52,6 +52,7 @@ int null_zone_init(struct nullb_device *dev) void null_zone_exit(struct nullb_device *dev) { kvfree(dev->zones); + dev->zones = NULL; } static void null_zone_fill_bio(struct nullb_device *dev, struct bio *bio, -- 2.25.1